Page 1

Photographic Chemicals

and Solutions By J.

I.

CRABTREE

and G.

Kodak Research

E.

MATTHEWS

Laboratories

Rochester, A". T.

AMERICAN PHOTOGRAPHIC PUBLISHING BOSTON, MASS. 1938

CO.


Copyright 1938

By

J.

I.

Made and

Crabtree and G. E. Matthews

Printed in the United States of America

by the Plimpton Press

•

Norwood

Massachusetts


PREFACE This book represents some of the knowledge acquired during the past twenty-five years in

compounding photographic

their application to

photography

in the

solutions

and studying

Research Laboratories of the

Eastman Kodak Company.

ERRATA Page 337

— Formula DK-20R — Replenisher Solution should read:

Kodalk Potassium Sulpliocyanate (Thiocyanate)

2 ounces, 290

grains

20.0

grams

290

grains

5.0

grams

Pages 341, 343, 345 Firm name should be spelled as follows: Lalance

&

Grosjean Corp.,

Woodhaven, N. Y. Page 359

— Index

Reference should read as follows: Fine-grain development 295, 337.

ui

November

1938.

i-K.

i»i rt 1 1

n n. WO"


Made and

Printed in the United Stales of America

by the Plimpton Press

•

Norwood

Massachusetts


PREFACE This book represents some of the knowledge acquired during the past twenty-five years in compounding photographic solutions and studying their application to

photography

Research Laboratories of the

in the

Eastman Kodak Company. The nucleus of this work was contained pare Photographic Solutions " (Brit.

quently

many

scientific

by the authors and in these

J.

How

Phot. 66: 365, 1919).

to Pre-

Subse-

papers cognate to this subject were published

their co-workers

and the material of practical value

papers has been extracted and combined

for reference purposes.

''

in the article

To

this compilation

in this single

volume

has been added consider-

able hitherto unpublished information.

The requirements

of the small as well as the large user of photographic

chemicals have been kept in mind throughout and

book

will therefore

be of value to

all

it

is

hoped that the

types of photographers including

amateurs, professionals, scientific investigators, x-ray, photofinishing,

photo-mechanical, and motion-picture workers.

Acknowledgment

who generously

is

due

to the various

manufacturers of equipment

supplied data and photographs, to Mr. C. E. Ives, to

Mrs. R. F. Quirk, and to our other numerous colleagues

in the

Kodak

organization for their suggestions and helpful criticism. J. I.

G. E.

November

1938.

Crabtree

Matthews


Digitized by the Internet Archive in

2010

http://www.archive'.org/details/photographicchemOOcrab


CONTENTS

Preface

.......... .........

PAGE iii

Introduction CHAPTER I.

II.

III.

...... ......

Terminology and Arrangement of Photographic Formulas Photographic Arithmetic and Conversion of For MULAS Apparatus and Methods of Use

IV. Materials for

....

Construction of Photographic Proc

ESSiNG Apparatus V.

Temperature Measurement and Control

...... ...... ......

VI.

Effect of the Water Supply on Photographic Solu

VII.

Technique of Mixing and Using Photographic Solu

tions

tions VIII.

6 15

Handling Solutions at High Temperatures

51

79

100

114 178

IX. Storage and Transportation of Chemicals and Solu

tions

X. Substitution of Chemicals XI. Stains on Negatives and Prints XII. Cleaning Photographic

191

214 230

Processing Apparatus and

Removal of Stains from the Hands and Clothing

262

.....

270

XIII. General Suggestions and Precautions

Photographic Chemicals XIV. Appendix

on Handling

....... ....... ....... .... ...... .........

A.

Formulary

B.

Table of Solubilities of Photographic Chemicals

C. List of

279

338

Manufacturers of Apparatus and Sup-

plies

341

D. Conversion Table of Fahrenheit, Centigrade,

AND Reaumur Degrees

347

Index of Formulas by Purpose

348

Subject Index

358


INTRODUCTION Chemicals chemicals, or

for 2.

photographic work are supplied either as

i.

individual

as mixtures of dry powders or solutions requiring only

the addition of water to prepare

them

for use.

The majority

photographers prefer to purchase their chemicals

in the

of

amateur

prepared form.

Within recent years an increasing number of advanced amateurs, pro-

and photofinishers have

fessional photographers,

age chemicals more extensively, but

also

begun

many workers and

to use pack-

the majority of

motion picture laboratories prepare their photographic solutions from the

component chemicals. It should be understood clearly, however, knowledge of the fundamental principles of solution preparation

that a

and use

is

important w^hether prepared powders or component chemicals

are preferred.

It is the

purpose of

this

book

to

supply such information.

In order to be able to prepare correctly any and every solution used in

photography, a knowledge of the properties of the chemicals used and

of the chemical reactions involved during the mixing

is

essential,

though

by adhering strictly to printed directions it is usually possible for an unskilled worker to prepare the developing and fixing solutions as generally used. However, instructions for the use of various materials differ; for example, in the case of some developing formulas it is recommended to dissolve the developing agent

should be dissolved tized

method

of mixing

first,

while according to others the sulphite

Both methods may be

first.

is

right,

followed, and especially

if

but

if

a systema-

the photographer

has a knowledge of the reactions involved, he can then proceed to mix

any photographic solution with confidence and, what is more, he will be able to locate the trouble if for any reason the solution does not work correctly after mixing.

In recent years automatic developing with processing machines has for motion picture and photofinishing work, and these machines necessitate the use of large volumes of solution which require special equipment for their preparation and handling. In each chapter, therefore, an attempt has been made to deal with specific meth-

been introduced, notably

ods for the handling of both small and large quantities of chemicals.


CHAPTER

I

TERMINOLOGY AND ARRANGEMENT OF PHOTOGRAPHIC FORMULAS A

solution of

any kind

is

obtained by uniformly mixing with and dis-

tributing a solid or a liquid through another liquid (or solid).

may

of gases in liquids

37% tion

is

a

solution of the gas, formaldehyde, in water; but this type of solu-

The substance being

rarely used in photography.

is

and the liquid The extent to which the

which

called the solute

in

solvent.

solute

its

Solutions

which

also be prepared, such as formalin,

and when the solvent

solubility

will

it

is

dissolved

dissolved

soluble in the solvent

is

is

called the

is

is

called

hold no more of the solute

it is

said to be saturated.

The degree

of solubility of

any chemical depends on the nature and

temperature of the solvent. a saturated solution

If

is

cooled

down

to a lower temperature, crystals

usually form which settle out until the saturation point

reached at that

is

particular temperature, though in the case of a substance like hypo, all

dust

is

called supersaturated solution of to

hypo grow

is

if

excluded, crystals do not separate out on cooling and a so-

added

is

until the saturation point

is

a small crystal

if

immediately form and continue

reached.

paring a saturated solution, therefore, water, cool to

However,

obtained.

to the solution, crystals

is

The

method

best

of pre-

to dissolve the chemical in hot

room temperature with shaking, allow

to stand,

and

filter.

For photographic work, saturated solutions are not recommended, because even though the solution care

any

taken to note

is

crystals

its

may

which

may have

been prepared correctly, unless

condition each time

it is

used, and to dissolve

have formed, serious errors

These errors can be avoided by

may

be introduced.

always using solutions of a definite per-

centage strength as will be explained

later.

Diluting to Volume. When a chemical is dissolved in water the volume of the solution is usually greater than that of the water used, because the particles or molecules of the chemical occupy a certain space

when liquid

in solution. is

In case two liquids are mixed, the final volume of the

not necessarily equal to the

before mixing,

it

may

be greater or

it

sum

may

of the volumes of the liquids

be

less.

Thus

fifty

volumes of

volumes of water at 7o°F. (2i°C.) produce ninety-seven volumes of the mixture and not one hundred. Moreover, equal weights of different chemicals do not occupy the same volume. alcohol

when added

to fifty


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

2

In photography

we

are concerned only with the weight or

volume

of

each chemical in a fixed volume of the solution, so that when mixing, the chemical should be dissolved in a volume of water appreciably less than

volume

that called for in the formula and then water added up to the stated.

Systems o£ Measurement.

— In photographic

practice, solids are

weighed and liquids are measured either by the metric or the avoirdupois system.

Although a large majority of photographers use the avoirdupois system of weights and measures, this system is inconvenient and complicated as compared with the metric system. The metric unit of length is the meter (m) (which means measure).

The meter

is

divided into one hundred parts called centimeters, abbre-

viated as cm.

The is

unit of

mass or weight

is

a platinum-iridium cylinder,

at the International

Bureau

of

the kilogram (kg) the original of which

which

is

in a special

thousandth part of the kilogram equals written g though preferably entiate

it

gram.

i

A

good rule

is

words of

to spell out all

in formulas.

unit of

volume

is

the

liter (1)

which

is

the

kilogram of pure water at the temperature of

namely 4°C. (39.2 °F.) and subjected Therefore,

The The gram may be

should be spelled out completely to differ-

from the term, grain.

one syllable

The

it

underground vault

Weights and Measures near Paris.

i

liter

of water weighs

one-thousandth part of the

The thousandth

part of a

liter

liter is

i

to

volume occupied by its

maximum

i

density,

normal atmospheric pressure.

kilogram or 1000 grams and

or the milliliter (ml) weighs

i

i

gram.

usually designated also as a cubic cen-

timeter (cc) although 1000 milliliters or

liter

i

equals 1000.028 cubic

centimeters {Report on Metric Units oj Volume, Brit. Standards Institu-

London, 1933). The difference between the two units is 28 parts which is so small as to be of no significance except in very precise scientific work. The term " cubic centimeter " has become so universally used that it is commonly accepted as the thousandth part tion,

in a million,

of a liter and will, therefore, be used in this

book with

this connotation.

For compounding metric photographic formulas, only grams, liters

in the case of the

U.

S.

currency which

is

a metric currency.

ginner should therefore think of grams and parts of a

were dollars and cents. 535 -iii grams.

100

and

cc,

are used, and fractions are always expressed as a decimal just as

gram

The as

if

be-

they

Thus, 5.35 grams corresponds to $5.35 or


TERMINOLOGY AND ARRANGEMENT In photography the following table

is

used:

Weight

drams (or drachms)

8

ounces

16

Volume

=

437"i grains

i

ounce

=1

ounce

=

pound

i

==

60 minims

drams (or drachms) 480 minims * 128 ounces

— Much confusion

Uniformity of Formulas. formulas could be avoided

Mees/

if

i

8 fluid

* 16 ounces

cation.

3

(or

=1

= = =

dram

fluid

drachm)

fluid

ounce

i

fluid

ounce

i

pint

i

gallon

in the conversion of

authors would adopt a standard for publi-

Ausserwinkler,- and others have suggested standards for

writing formulas but for practical use in publication, these have certain objections.

The

simplest standard, perhaps,

is

the liter (32 ounces) or

quarter fraction thereof, 250 cc, 500 cc, and 750 cc (8 ounces, 16 ounces,

and 24 ounces respectively) I

for tray dilutions,

and 4

liters

gallon) or quarter fraction thereof for tank dilutions.

always be published total

in

both metric and avoirdupois equivalents with the

volumes on the above

The

(128 ounces or

Formulas should

basis.

variation of the British measure from the American

is

sometimes

a source of confusion, because in the former, the British imperial gallon

(160 ounces) equals 4.546 3.785 liters (see page 6). tion of the British

liters

whereas the U.

It is

Chambers

of

S.

gallon (128 ounces)

is

encouraging to note that the Associa-

Commerce have by resolution suggested The Metric Committee of

the adoption of the liter as the standard.^

American Chemical Society have

the

equivalents should be published for

also

recommended

A very

recommended above.

that metric

photographic formulas

This world resolution

tion to avoirdupois values.*

the standard

all

is

in

in addi-

agreement with

clear article on the use of the

metric system in photography has been published by Chappell.''

Order of Chemicals

in a

Formula.

— When mixing photographic

solutions, the importance of following manufacturers' instructions can-

not be overestimated.

The

quantities

been established by extensive

tests

and the order of ingredients have to change them is very apt to

and

affect the useful properties of the solution. *

page

These are U.

S. units.

For

1

Brit. J. Phot. 64, 535 (ipi/)-

2

Phot. Rimd. 62, 130 (1925). Ind. Eng. Chcm. News Ed.

3

&

2, 2

(Oct. 10, 1924).

Amcr. Chcm. Soc. 81 (1925). Camera (Phila., Pa.) 47. i45-i55 (Sept. 1933)-

* Proc. 5

a discussion of the British imperial measure, see

6.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

4

The

order in which the ingredients are arranged in the formula

In some cases water

importance.

is

placed

first,

is

of

but

in other cases last,

as a general rule it should appear last and be written " water to make." With two- and three-solution developers, an exception to the rule maybe made if only one or two chemicals, such as sodium carbonate, are to be dissolved, when the total volume of water should be given first. It is also useful with most developer formulas (pyro and amidol excepted) to

include the expression, " water (about i25'-"F.) (52°C.) " at the top of

the formulas in a volume sufficient to dissolve readily It

is

all

the chemicals.

unnecessary, except in the case of difficultly soluble chemicals like

alum, borax, (52°C.).

to use

etc.,

Also,

water at a temperature higher than i2 5°F.

too hot water

if

is

used

much time may be wasted

in

cooling the solution to a temperature suitable for use.

When it is

mixing very large volumes of solution, as

sometimes simpler and more practical

will

be discussed

later,

to avoid the necessity of heat-

ing water higher than 65° to 7o°F. (18° to 2i°C.).

For simplicity, the volume given at the top of the formula should be

Then total volume of the solution. given as " cold water to make," the developer

an even quarter fraction of the the final dilution

more apt

to

is

be nearer the temperature for use than

if

if is

no instructions

were given.

Whenever a solution must be diluted for use, the expression " Stock Solution " should precede the formula. An example embodying these suggestions

is

as follows:

A

Stock Solution

Avoirdupois

Water (about

125° F.){52°C.)

Elon

Sodium

ounces

16

grains

60

Sulphite, desiccated

Cold water to

ounce ounce ounces

Vi Y^

Hydroquinone

make

32

Metric 500.0 cc 4. 1

15.0 15.0

grams grams grams

l.o liter

Stock Solution B Water

32

Sodium Carbonate, desiccated Potassium Bromide

30

The chemicals should be given dissolved, servative,

which i.e.,

in the case of a

V^

ounces ounce grains

in the order in

developer

sulphite, bisulphite,

is

1.0 liter

15.0 2.1

grams grams

which they are

usually as follows:

or metabisulphite;

2.

to i.

be

pre-

developing

agent; 3. accelerator or alkali such as carbonate; 4. restrainer or bro-

mide; If

5.

" water to

make."

a strong alkali, such as sodium hydroxide (caustic soda)

the water should always be written

first

and expressed as

is

given,

" cold

wa-


TERMINOLOGY AND ARRANGEMENT because on mixing, considerable heat

ter/'

is

5

evolved and the solution

is

apt to boil with explosive violence. If the formula contains sulphuric acid, the acid should appear at the end of the formula so that the concentrated acid will be added to the water. If this procedure is reversed, that is, the water added to the acid,

serious burns

may

be produced by a spattering of the acid caused by the

excessive heat generated on mixing.

Names and

Abbreviations,

— Although

it

common

is

designate particular chemicals by several different names,

practice to

it is

suggested

that the standard chemical terminology found in any good textbook of

Such archaic terms as carbonate of sodium, bichro-

chemistry be used.

mate etc.,

of potash, soda crystals, sulphuret of hydrogen, potassa carbonate,

In the same class

should be discarded.

carb., pot. bromide, ammonio-chloride, etc.

names

is

Sodium thiosulphate, used

commonly used

chemical

is

"'

name sodium

has been used for so

that practically everyone understands

it

is

commonly

is

This

not a fixing agent,

many years by photographers mean sodium thiosulphate.

in a formula,

preferably as a io9f solution to be added as so

than a dram

is

hyposulphite.

— When quantities

Small Quantities of Chemicals. i gram or 15 grains are included

under

to

It

in photographic practice.

quite a different substance and

but the term " hypo

be used.

of preferred chemical

as a photographic fixing agent,

called " hypo," an abbreviation of the

less

abbreviations like soda

list

given in the table of solubilities in the Appendix, page 338.

includes most of the chemicals

latter

fall

A

of chemicals

they are expressed

many

cc or drams.

If

required, an even quarter fraction thereof ought to

This plan avoids using " drops " as a unit of measure which

is

method of measuring the volume of a liquid. There is wide variation in the number of drops to a dram with liquids of different specific gravity. Even drops of the same liquid vary in size according to the shape of the mouth of the discharging vessel. Other a very uncertain

factors influencing the size of the drop are the rate of delivery of the liquid to

from the

vessel, the surface tension of the liquid,

which the mouth of the vessel

is

A

moistened.

and the extent

note published in the

some idea of the variation in shown is from 45 drops The average drop from with ammonia to 138 with ethyl alcohol (95 /c ) the usual dropping bottle or burette used in technical research work Photographic Journal of America

^

gives

volume which may occur. The range

in the table .

measures about

i

minim

or approximately one-twentieth of a cc.

Directions are given later for mixing percentage solutions. 8

Phot.

J.

Amcr.

S9,

412 (1922).


CHAPTER

II

PHOTOGRAPHIC ARITHMETIC AND CONVERSION OF FORMULAS In photographic practice, solids are weighed and Hquids are measured

by the avoirdupois

either

The

or the metric system.

following tables of weights and measures give

all

the equivalent

values required for converting photographic formulas expressed either in

metric or U.

S. liquid

measure.

Weights and Measures

— Conversion Tables

Avoirdupois to Metric Weight Pounds


:

..

ARITHMETIC AND CONVERSION OF FORMULAS Measure

British Imperial Liquid to Metric Quarts

Gallons

Drams

Fluid

(J'^x^s

CenUmeters

''»»*^^'»

1.0

4.0

160.0

1280.0

4546.0

4.546

0.25

1.0

40.0

.UO.O

1136.0

1.0

8.0

1.136 .02841

0.003125 0.2200

0.125 0.03520 35.20

0.8800

28.41

1.0 (60

min.)

3.551

0.2816 281.6

.003.551

.001

1.0

1000.0

1.0

Solid Conversion Values Grains

tirains

1

.,

l

<>

niiart

per British imperial quart multiplied by 0.833 = ounces f,, «,;! ,' .rlT.- ..^ (40 fluid ounces) pounds ^^^ ""''' """•^'^s) Grains per British imperial quart multiplied by 0.05696 = )>rams per liter = ftrams per liter Ounces per British imperial quart multiplied by 24.92 = grams per liter Pounds per British imperial quart multiplied by 398.7 = grains per British imperial quart Grams per liter multiplied by 17.54 = ounces per British imperial quart Grams per liter multiplied by 0.0401 Grams per liter multiplied by 0.002506 = pounds per British imperial quart

Ounces Pounds

]

Ounces

(fluid)

per British imperial quart multiplied by

Ounces

(fluid)

per British imperial quart multiplied by 25.00 = cubic centimeters

j

Liquid Conversion Values 0.8

= ounces

(fluid)

per U. S.

quart per

liter

Cubic centimeters per

liter

= ounces

multiplied by 0.03999

(fluid)

per Brit-

ish imperial quart

British texts sometimes refer to the Winchester

which equals

2

im-

perial quarts.

Example

of a

— When

Formula Conversion. it may

pressed in grains, ounces, anci pounds,

a formula

is

ex-

be converted into a metric

formula by using the above conversion values which take into account the difference between 32 ounces and

After a conversion has

liter.

i

been made, the values obtained should be rounded

off to

working quantities.

Tiie-errorintroduced in rounding

not be greater than

3%

and the

ratio

give convenient

off

a value should

between chemicals such as Elon

and hydroquinone or carbonate and sulphite should not be changed. Thus a developer formula for a 3^ gallon tank would be converted as follows

T^ Formula ,

Water (about

125° F.) (52° C.)

1

149

Elon

Sodium Sulphite (desiccated) Sodium Bisulphite Hydroquinone Sodium Carbonate (desiccated) Potassium Bromide Cold water to

Water (about

125° F.) (52°

....

.

Hydroquinone Sodium Carbonate (desiccated) Potassium Bromide

make

1 ounce 139 grains 83 grains 3hi gallons

Direct ounces 32 423^ grains

C).

Sodium Sulphite (desiccated) Sodium Bisulphite

ounces 240 grains grains grains

Gallon (Avoirdupois)

1

Elon

Cold water to

96 288

make

Conversion to

gallon grains

10

3

27'^ 82J4 165 23?^ 1

ounces 4 grains grains grains grains grains gallon

Rounded

Off 32 ounces 43 grains 3

ounces

28 grains 82 grains 165 grains 24 grains 1 gallon


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

8

Conversion to 4 Liters (Metric) Rounded

Direct

Water (about

125° F.) (52° C.)

10

..

Sodium Sulphite (desiccated) Sodium Bisulphite Hydroquinone Sodium Carbonate (desiccated) Potassium Bromide

make

Cold water to

liter

Off

1.0 liter 2.9 ftrams

2.94 grams 90.3 grams 1.88 grams 5.64 grams 11.28 grams 1.62 grams 4.0 liters

Elon

90.3

grams

1.9 grams 5.6 grams 11.3 grams 1.6 grams 4.0 liters

a formula called for 453^ grains and this quantity were cut to an

If

even 450, the difference would not be detectable by photographic means, though if a quantity of 6^ grains were cut to 5 grains, the error (23%) would be serious. In rounding

when

3.82

rounded off to

the quantity, for example, of Elon, in a formula, an

off

4.7% may

error of

grams

off in the

25.0 grams, a

separately

is

be introduced in bringing

made

is

opposite direction, that

7%

error

is

is,

if

if

to a certain value, as

the hydroquinone

26.8 grams

between the Elon and hydroquinone

do not change the

ratio

is

12%

is

which

is

in

rounding

between the constituents of a formula.

i

liter

the basic

liter

Liter

or :

pound

some value

practice of con-

in the avoirdupois

later time, reconverting the 8 gallon

liters is

fundamentally unsound.

i

quart formula.

120 Gallon Conversion.

a metric formula (grams per

I

The common

quart.

The 96

formula should be obtained by a direct conversion from

because each gram to

best

derived, whenever possible, from one

liter or i

96 ounces or to 3

ounce or 3 i

The

usually permissible in photographic work.

system such as 8 gallons and, at a

I

values

off,

verting a liter formula, for example, to

The

off

below 3%. is to keep the error, in rounding introduced would error that could then be be less than

basic formula, such as

to

in

changed.

watch that errors

Working formulas should be

formula

made

introduced and the

rule to accomplish this

The maximum

is

rounded

Neither of these errors taken

introduced.

It is important, therefore, to

6%

is

very serious in photography but since they were

opposite directions, a total error of nearly ratio

up

it

Then

4.0 grams.

in the

in the

i

liter) to liter

— A very rapid conversion

a 120 gallon

of

formula can be made

formula can be changed directly over

120 gallon formula with an error of

less

than 0.2%.

a simple matter to express fractions of a pound in ounces (avoir.) or to break the ounces into quarter fractions of an ounce. This scheme It is

is

of value, obviously, for large scale work.

In photography two kinds Percentage Solutions. are commonly used as follows:

of solutions


ARITHMETIC AND CONVERSION OF FORMULAS A A

A. B.

9

solid in a liquid.

liquid in a liquid.

The misunderstandings which have method

ing the correct

arisen from time to time regard-

of preparing solutions of a definite percentage

strength are due to the fact that there are three ways of doing

make a

example, we can

For

it.

s7( solution of potassium bromide as follows:

Dissolve 5 grams in loo cc of water. Dissolve 5 grams in 95 grams of water making 100 grams of solu-

1.

2.

tion.

Dissolve 5 grams in a

3.

In case

A

i.

little

we might have 102

chemist would use method

mass

water and add water to make 100

2.

because he

and not

of the solids in solution

and

cc of solution

is

in the

photographic work to

fill

cc. cc.

interested chiefly in the

volume, but method

used when preparing photographic solutions because tice in

about 97

in case 2.

common

it is

and

vessels to a definite level

3. is

prac-

it is

con-

venient to measure stock solutions or small quantities by taking a definite

volume of the

Method

solution.

i

not used for the reason that equal

is

weights of different chemicals do not occupy the same volume.

The percentage strength of a photographic solution, how much of the chemical is dissolved in 100

indicates

Table of Solubilities

(see

To

7%

prepare a

grams

cc.

ured

7

If

Appendix, page 338).

in

solution of potassium bromide, therefore, take 7

of the salt, dissolve

100

in a little water,

it

we now measure out 100

grams of the

I

10%

solution of a solid

ounce and making up to 10 ounces with water.

figures into solution.

to make we have meas-

and add water

cc of the solution

solid.

In the avoirdupois system a ing

therefore, merely

cc of the solution

grams and cc we have, roughly, 30 grams

Strictly speaking, this

is

in

not correct since

= 29.57

is

made by

tak-

Converting these

i

300

cc, or

ounce (U.

a

10%

S.)

ounce

=

28.35 grams and

i

10 fluid ounces

equivalent to 28.35 grams in 295.7 cc or 9.6 grams in

is

fluid

ounce (U.

S.)

cc so that

i

in

100. If a

photographic solution

or 3, the error involved

is

is

less

made by any

than

3%

of the above methods, 1,2,

and therefore

negligible for ordi-

nary photographic purposes, though since the correct method est, it

is

the easi-

should be followed.

Although somewhat of an anomaly, solution of a substance like

occupy a space of 100 cc)

A 10%

it is

possible to prepare a

100%

hypo by dissolving 100 grams (which do not

in sufficient

water to make 100 cc of solution.

solution of a liquid in water

is

made by

taking 10 cc of the


10

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

liquid

and adding water

to

make loo

cc.

The concentrated form of mean

certain liquids used in photographic practice does not necessarily

that the solution contains

ioo%

of the liquid or gas in question.

Sul-

phuric acid, pure concentrated, for example, represents a 95/^ solution; nitric acid, pure concentrated, 65%; hydrochloric acid, pure concentrated,

28%

35%;

37%

formalin,

ammonia

of

gas.

and ammonia,

of the gas, formaldehyde;

When

preparing a dilute solution of any of these

concentrated liquids for photographic use, however, their strength

100%.

usually taken as

prepared by taking

adding water

to

i

make

A 10%

solution of

ammonia,

When

diluting

most concentrated

the acid should always be added slowly to about sired

volume of water.

The

90% is

danger of the acid

articles,

much

the authors would clearly define the

if

Finally, water

the solution to volume.

In the publication of photographic

avoided

acids,

of the total de-

spattering on the hands and causing serious burns.

make up

is

solution should be stirred while adding the

acid to insure thorough mixing, otherwise there

should be added to

is

(28%) ammonia and

part of the concentrated 10 parts.

for instance,

whenever the term " percentage solution

" is

confusion would be method used by them

introduced.

Inconsisten-

and mistakes introduced by a lack of understanding of percentage solutions have been pointed out by Dobson ^ and Lockett.- Although cies

made is slight when small quantities are measured, it becomes when the percentage of the substance dissolved is 25%, 30%,

the error serious

or greater.

â&#x20AC;&#x201D;

Usefulness of Per Cent Solutions. The great advantage of any solution in parts per hundred is that a definite mental picture is at once created of its relative strength, and by means of a number of stock solutions it is possible to compound certain formulas by simply measuring out a definite volume of each solution thus dispensing with a balance. Thus supposing we have a 10% solution of potassium ferricyanide and of potassium bromide already at hand and it is

stating the strength of

make up

desired to

the following solution:

Potassium Ferricyanide Potassium Bromide Water to

then

it is

grams

2.3 grams 1.0 liter

only necessary to measure out 60 cc of the ferricyanide solu-

tion, 23 cc of the

solution

6.0

is

bromide solution, and add water up

made.

1

Camera Craft

2

Brit. J. Pilot. 70, 95 (1924).

2j, 2gi (1920).

to

1000 cc and the


ARITHMETIC AND CONVERSION OF FORMULAS In the case of very concentrated solutions

it is

11

not always possible to

use this method, though in view of the time saved and the accuracy of the

method

should be applied whenever possible.

it

Suppose a formula

gram.

calls for o.i

impossible to weigh this

It is

quantity accurately on the usual photographic scale, but by measuring out is

I

cc of a

less

10%

An

solved.

and adding

solution,

than lo cc

by means

is

end

mark and then allowed

until the liquid

The to

liquid

is

problem

a calibrated

is

sucked up into the tube

run out by placing the finger over the

even with the mark.

is

raising the finger slightly

which

of the chemical pipette,

tube with an orifice at one end. past the

this to the mixture, the

accurate and convenient method of measuring volumes of

It is

then discharged by

from the end.

â&#x20AC;&#x201D;

Photographic Arithmetic. much greater than

tity of solution

It is

often required to mix up a quan-

by the formula,

that given

in

which

case the photographer must perform a very simple exercise in arithmetic in

order to secure the desired result.

cate the

A.

method

Mix

The two

following examples indi-

of solution of such simple problems.

6 ounces of solution according to the following formula: Potassium Ferricyanide

4.0

Water

grams

10.0 grams 100.0 cc

Hypo to

(In order to simplify the arithmetic,

will

it

be assumed that

equals 30 cc instead of the more exact value, 29.57 cc.)

ounces

= 6 X 30 =

180

little

error introduced

is

X

^

ounce

X4=

6

7-2

18 grams of hypo.

Dis-

water and make up to 180 cc or 6 ounces.

The

grams of ferricyanide and 180/100 solve these in a

we need 180/100

Therefore,

cc.

i

Now,

1.7'

r

which

is

10

usually permissible in photographic

work. B.

How would

you mix

i

pint of a

7%

solution of sodium sulphite?

To make 100 ounces of a 7'^r solution we need 7 ounces of sulphite. i-i2 ounces Therefore, to make i pint (16 ounces) we need 0.16 X 7 i ounce dissolve therefore, or I ounce 53 grains. To prepare the solution, pint). ounces 53 grains of sulphite in water and make up to 16

= ( i

The Meaning

of " Parts."

â&#x20AC;&#x201D;

It is ofte^i

say, 10 parts of a solid in 100 parts of water. ingless because a solid chemical

though

if

the metric system

then grams and cc

may

is

is

recommended

weighed while a liquid

used, since

i

to dissolve,

Such a statement is

is

mean-

measured,

cc of water weighs

i

gram,

be considered synonymous with parts.

In the case of liquids, parts should be taken as meaning units of volume, and in the case of solids as units of weight. A " part " may there-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

12

fore

mean

either a gram, a ton, a cc, or a gallon so long as the other

same

quantities are reckoned in the

A

three partsl

B

one part

mav may mpan mean

V .

units of weight or volume.

(A ^oo

J

If the

and

avoirdupois system

liquids,

if

is

cc

^ IBioocc

A

1=;

^

ounces

1^5

ounces

f

nr or

J <

Thus:

J .

used and the formula contains both solids

ounces (liquid) and ounces (solid) are substituted for

" parts," the error involved falls within permissible limits.

Problem:

Mix

I

gallon of solution according to the following formula.

Sodium Sulphite

10 parts

Pyro

1

Water

Now,

I

part

100 parts

to

gallon equals 128 ounces.

Therefore, dissolve 12.8 ounces

of sulphite in water, add 1.3 ounces of pyro, and

make up

to

gallon.

i

For the sake of simplicity and clearness, however, exact quantities should always be given rather than " parts."

If this

is

done and a stand-

ard volume adopted for the total volume of the solution, directions for

mixing

will

be

much

easier to follow.

The Hydrometer

Test.

— Many photographers are accustomed

to

making up their stock solutions of hypo, carbonate, sulphite, etc., by means of the hydrometer. This method has the advantage that in case the hypo, for example, has become moist and contains an unknown quantity of water, a definite reading on the hydrometer will give a solution of the

When

same strength as

a stock solution

is

perfectly dry chemicals

if

had been used.

made from moist chemicals by

weighing, the

by the presence of water may be as high as 25% or 509^ The hydrometer method has the serious disadvantage that the ad-

error caused

justment of a solution to the required strength takes considerable time, the hydrometer reading does not convey

any idea

as to the percentage

strength of the solution, and the reading varies with the temperature.

For instance, say, 45 ister all

if

Baume

a stock solution

made with hot water and

this registers,

when

may

It is therefore absolutely necessary either to

48 or 50 Be.

readings

is

(Be.) on the hydrometer, on cooling, the liquid

the solutions have cooled to

room temperature,

reg-

make or to

prepare a table giving the variation of density of each solution with temperature.

For example, the

specific gravity of acetic acid at 59 °F.

(i5°C.) with increasing concentration of acid increases to a value of 1.07 at

A

hydrometer

80% is

and then decreases

to 1.058 at

99%

maximum

acid.

useful, however, in checking the strength of certain

liquid chemicals such as alcohol, acetic acid

and sulphuric

acid.

If

a


ARITHMETIC AND CONVERSION OF FORMULAS solution

known

is

13

pure ethyl alcohol and water, for ex-

to contain only

ample, then from the hydrometer reading at a definite temperature, the percentage strength can be determined with accuracy.

Mixing stock solutions by hydrometer cause

it is

much

simpler to

compound

hydrometer reading, however,

sometimes a rough check that the solu-

been mixed correctly.

tion has

A

is

recommended beby weighing. A subsequent

test is not

these

hydrometer

The only way

test of a

mixed developer has no meaning whatever.

to test a developer

tographic material for which

Hydrometer readings no relation

to the

it is

is

to

develop actually therein the pho-

intended.''

of acid hardening fixing baths also bear little or

time required for the film to clear and therefore repre-

method

sent an unreliable

of checking the condition of a fixing bath

(see further details on page 162).

as

Hydrometers are graduated according to many different scales such Baume, Twaddell, etc. Others read directly in specific gravity which

volume of the liquid to the weight same volume of water at a standard temperature. Dilution of Liquids. It is often required to reduce the percentage strength of a solution. For example: How would you mix two gallons gives the ratio of the weight of a given

of the

â&#x20AC;&#x201D;

of 289^ acetic acid, from a supply of glacial acetic acid?

To make 100 cc of 28% acid we need 28 cc of glacial acid. To make i cc of 28% acid we need 28/100 cc of glacial acid. To make 2 gallons 7570 cc of 28'/^ acid we need 28 X 75-7 ^2120 cc (71^ ounces) of glacial acid.

Therefore take 71? ounces 2120 cc of glacial acid and add water to

make

To

2

gallons 7570 cc.

dilute a solution three times

we do not add

three times the

of water but approximately twice the

volume and so on.

One volume

volumes of water

of solution plus about

solution which

is

2

volume

For example:

=

3

volumes of

one-third as strong or three times as dilute as the

original.

Stock Solutions.

â&#x20AC;&#x201D; A stock

solution

is

a concentrated solution to

which water is added before use. In the case of simple solutions containing only one salt such as potassium bromide, sodium carbonate, etc., a 10% solution is most convenient because by dividing the volume of the solution in cc by 10 we get the number of grams present in the solution.

Thus 3

"

75 cc of

10%

potassium bromide contains

Photographic Methods of Testing Developers Amcr. Ann. Phot. 36, 184 (1922).

^9> 153 (1922)

;

"

by

7.5

J. I.

grams. Crahtree.

Brit. J. Phot.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

14

The

limiting strength of solution

which

it is

possible to

make

particular case depends on the solubility of the chemical,

in

any

and as the

solubility diminishes with temperature a solution should not

be made

stronger than a saturated solution at 40째F. (4.4째C.), otherwise in cold

weather the substance would crystallize out (see table of

solubilities

given in the Appendix, page 338).

A sible

stock solution of sodium sulphite should be

(20%

tion oxidizes very slowly

solution

it

made

as strong as pos-

of the desiccated salt) because at such a strength the solu-

and

will therefore keep,

combines with the oxygen

in the air

whereas in weaker

very readily and

is

then

useless as a preservative.

In making up any stock solution,

its

strength should be such that

can be diluted easily to give a solution of working strength. ample, hypo

often mixed as a

is

volume of water a triple, or

2 5

%

solution

50% is

solution

it

For ex-

and then by doubling the

This plan of mixing double,

obtained.

quadruple strength stock solutions

is

often a valuable

means

of

saving both space and time.

The term is

"

Stock Solution " should precede a published formula that

to be diluted for use, as otherwise there

a formula

may

is

always the possibility that

be mistaken for a working solution.


CHAPTER

III

APPARATUS AND METHODS OF USE

Types of Weighing Devices. Apparatus for weighing chemimay be classified conveniently into several sizes according to the maximum volume of solution to be prepared as follows: Four Liters (i Gallon). A small double pan scale weighing to cals

100 or 200 grams {y\ to studio use.

Fig. ia

Two common

— Small studio

One Hundred of

ounces)

7

is

satisfactory for amateur or small

types are shown

in

Figures

i.A

or lal)oiator>- scale, capacity 100 prams

—A

Liters (25 Gallons).

for the

moderate

size studio,

ounces).

(3'.

scale having a capacity

5000 grams (about 10 pounds) should be provided.

ample

and iB.

It

should be

photofinishing plant, and x-ray

laboratory (see Fig. iC).

Four Hundred Liters (100 Gallons).

— For

large commercial es-

tablishments, photofinishing plants, and small motion picture laboratories a scale

weighing from 8 to 10 kilos

(

18 to 22 pounds)

is

required.

shown in Figure iD is very satisfactory. Oscillations of the pointer are damped by an oil dash pot. The capacThis model may ity of the model shown is 12.5 kilos (27-^ pounds). also be used for small scale weighing by removing the large scoop and its For. rapid weighing, the type

tare weight.

Two Thousand Liters weighing

in either

(500 Gallons) or More.

— Platform

scales

kilograms or pounds (and ounces) should be pro-


A

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

16

Two

vided for work requiring very large volumes of solutions. are

shown

These are satisfactory

in Figure 2.

for large

types

motion picture

laboratories or very large commercial plants. It

may

be desirable to have two or more types of scales in the larger

establishments to facilitate rapid mixing of small as well as large vol-

umes

of solution, such as the type

shown

in

Figure

iD and

Figure

2

and 2B.

Fig.

Small laboratory scale, capacity 500 grams (i pound). Torsion Balance Co., New York, N. Y.

IB

Weighing Very Small Quantities sionally required to

mix very

of Chemicals.

gram

is

needed which

will

For such work, a sensitive

weigh accurately

(or fractions of a grain).

Figure

3.

Type A with

general use.

Two

is

0.02

in

hundredth parts of a

types of balances are illustrated in

the hinged glass cover

Its sensitiveness

It is occa-

dilute solutions of chemicals, particularly

of dyes for toning or desensitizing baths.

balance

â&#x20AC;&#x201D;

Courtesy

gram

(

is

a practical balance for

1/32 grain) and

its

capacity,

120 grams (4 ounces).

Type B

represents a

more accurate balance commonly used

in

ana-


APPARATUS AND METHODS OF USE lytical

work.

rider as

It is

equipped with a calibrated chain instead of a movable

One end

on type A.

arm, the other to a vernier weight of the chain

The chain

is

17

is

added

moved by

of the chain

is

attached to the balance

As the vernier scale is lowered, more the balance arm and less as it is raised.

scale.

to

rotating a crank extending through the side of

the balance case.

Fig. ic

â&#x20AC;&#x201D; Double

pan

scale,

Courtesy Torsion

capacity 5 kilos (10 pounds).

Balance Co.,

New

York, N. Y.

Balance pans should preferably be made of a non-corroding metal, such as nickel, 18-8 stainless steel,* or nickel-plated brass, although porcelain pans are also satisfactory.

Containers for Mixing. glass flasks

*

known

â&#x20AC;&#x201D; For small volumes

as Erlenmeyer

flasks are the

There are several manufacturers of the type of

(18% chromium-8%

The

of solution, conical

most suitable mixing

stainless steel

known

as

18-8

i8-8 stainless steel to photographic solutions varies somewhat, however, depending on the content of carbon, molybdenum, titanium, zirconium, selenium, etc. and the heat treatment which the steel has received at the mill. A method of testing 18-8 stainless steels for their resistance to corrosive attack by photographic solutions is described on pages 53-57-

Two

nickel).

corrosion resistance of

recognized text books on stainless steel are the following

:

" Stainless Iron

and

Steel," by J. H. G. Monypenny, Chapman & Hall, London, 1926, and "The Book of Stainless Steel," Amer. Soc. of Steel Treating, 7016 Euclid Ave., Cleveland, Ohio.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

18

vessels.

(see Fig.

For larger volumes use enameled pails or hard rubber buckets 32D, page 66) For still larger volumes, tanks, drums, or crocks .

of a suitable material such as

ware, or an 18-8 stainless

Fig. id

wood, Alberene stone, hard glazed stone-

steel,

â&#x20AC;&#x201D; Single pan and scoop

such as Allegheny metal (Fig. 4)

scale.

may

Courtesy Fairbanks, Morse & Co., Chicago, 111.

be used.

For large scale work the solution should be pumped or emptied

by gravity

into a larger storage tank

mechanical

stirrers

and allowed

where

to clear

by

it is

thoroughly mixed with

settling before

emptying into

the circulating tank (see Fig. 19, page 39).

Weighing and Measuring.

â&#x20AC;&#x201D; Chemicals

should

preferably

be

room which is separated from the developing room and care should be taken when handling such

weighed out and the solutions prepared

in a

substances as hydroquinone, resublimed pyro, potassium ferricyanide, etc.,

not to shake the finer particles into the

air,

otherwise they

may

enter

the ventilating system and settle out on benches or shelves where negatives

and prints are stored.

Such chemical dust almost invariably pro-


APPARATUS AND METHODS OF USE

19

duces spots and stains (Fig. 5) particularly if the sensitive materials are wet when contaminated by the dust particles. It is good practice to

mix developers and

fixing baths in separate rooms, in order to avoid

possible contamination of developers

â&#x20AC;&#x201D; Platform

Fig. 2\-

with beam.

scale

Fairbanks, Morse

&

Fig. 2B

and

mixing vessel do not shake the paper but drop water to flow over

it

â&#x20AC;&#x201D;

dial.

111.

pieces of paper

any

bath chemicals.

fixing

Platform scale with Courtesy Toledo Scale Co., Toledo, Ohio.

Courtesy

Co., Chicago,

Weigh out chemicals on

by the

after transferring to the

it

into the sink

so as to dissolve the dust.

and allow

Larger quantities are

most conveniently weighed out in buckets. Shallow wooden trays about 16 by 20 inches and lined with rubberized cloth are useful containers for weighing out large quantities of chemicals previous to dissolving (Fig. 6).

A

different tray preferably should be used for each chemical

by marking the or

tray.

Metal scoops made of aluminum,

and

labelled

stainless steel,

Monel may be used effectively for weighing large quantities of chemiThey should be washed out carefully after weighing each different

cals.

chemical to avoid contamination.

The

zero points on

quent intervals tant

all scales

and balances should be checked at

to insure accurate weighing.

when using

This

is

fre-

especially impor-

sensitive balances for weighing small quantities.

For small volumes

of liquids a glass graduate

marked

off in cc or


V

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

20

For larger volumes use a bucket previously

ounces should be used. graduated, or

mark

off the inside of the

tank or crock used for mixing

(see discussion on paddles on pages 24-2 7 )

When

.

measuring a liquid

a glass graduate place the eye on a level with the graduation

Fig. 3A

â&#x20AC;&#x201D; Chemical and dyestuffs balance with sion Balance Co.,

New

in the liquid until the lowest part of the

with

this level.

it

warm

is

drawn up the

sides so that

made

as

shown

liquid contracts

Dissolving.

in Figure 7

and

at

its

solubility

and degree

temperature of the solvent, and the rate of

effect

is

side-

All readings

room temperature because

on cooling.

â&#x20AC;&#x201D; The rapidity with which a substance

solvent depends on

stirring

on viewing

appears as though the liquid has two surfaces.

should be a

curved surface coincides

to capillary attraction the liquid in contact with

the walls of the graduate

ways

Courtesy Tor-

calibrated rider.

York, N. Y.

pour

Owing

in

mark and

dissolves in

any

of fineness, the nature

and

stirring.

The method

of

very important and the shape of the paddle has considerable

on the rate of dissolution (see paragraph discussing paddles on

pages 24-27).

Most

solutions are rendered completely

homogeneous


APPARATUS AND METHODS OF USE

21

only with difficulty. caustic soda, will

if

For example, when mixing solutions containing they are not thoroughly agitated the heavier caustic liquid

remain at the bottom and when used the solution

form composition.

them thoroughly

Fig. 3B

It is

warm is

water with

usually

The

way

is

is

usually

more

stirring.

warm enough

Water

to dissolve

is

be of uni-

solutions to stir

Courtesy Christian Becker,

soluble in

of mixing a solution

will not

all

complcttYl and before use.

balance using calibrated chain. Inc., New York, X. Y.

Since a chemical the quickest

after the mixini:

:it:;)in

— Chemical

important, therefore, with

to

warm

water than

in cold

powder and dissolve

at a temperature of

it

in

i25°F. (52°C.)

most photographic chemicals

readily.

use of water at higher temperatures, especially boiling water,

is

not

recommended because there may be danger of decomposing the chemical and if the solution is to be used immediately, it will require considerable time to cool the solution to the required temperature. Since most solutions are intended for use at ordinary temperatures (65° to 7o°F.) (18° to 2i°C.), the solution

must be cooled

off

if

very hot water

again

if it is

is

used for dissolving,

required for immediate use,


:

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

22

though usually the time taken to do

would be taken up

this is less

than the extra time which

in dissolving the chemicals in cold water.

When

mixing, therefore, as a general rule, dissolve each chemical in as small

a volume as possible of water at about i25°F. (52°C.), cool, and dilute

Fk;. 4

— Stainless

stt'cl

(iS-S) mixinti tank and

The gallons or 75 liters capacity). hard rubber faucet and pipe is inserted through a stirrer

(20

and held

soft rubber stopper

in place

with a metal

plate.

with cold water.

oughly

if

After diluting with water, shake the solution, thor-

in a bottle,* or stir

if

in a tank, otherwise the

water added will

tend to float on top of the heavier solution.

When

mixing a solution

in

a tank,

it is

possible to proceed in one of

two ways A. Dissolve the chemicals separately in buckets or small vessels, add

each solution to the tank

ume B.

Add

filled half

*

in the

necessary order, and then dilute to vol-

with cool water. the solid chemicals directly to the large mixing tank which or three-quarters full with water at 65° to 75°F.

To permit thorough mixing,

the capacity of the bottle should be

than the volume of the solution to be mixed.

is

(18° to

somewhat larger


APPARATUS AND METHODS OF USE 24°C.).

23

After diluting to volume with cool water, the temperature of

the solution will be about right for immediate use.

It

is

very important,

however, when mixing very large volumes of solution, such as looo gallons (4000 liters) or more, to avoid the necessity of cooling the final solu-

FiG. 5

— Spots produced

on film by chemical

dust.

Hypo

(left)

and potassium

ferricyanide (right).

Fig. 6

— Trays lor weighing chemicals.

tion, as this operation takes considerable time,

which

may

be shortened

only by the use of an expensive refrigeration installation.

For large scale mixing, method B.

is

usually to be preferred.

practice to dissolve the chemicals directly in the tank w^hich

developing and

facilities

is

It

is

should be provided for filtering the solution at

some point between the mixing and developing tanks. When dissolving finely powdered Caking of Chemicals.

cated

salts,

there

is

bad

used for

a tendency for the salt to form a hard cake

quantities of the chemical are

dumped

if

desic-

large

into the water without stirring,


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

24 or

if

the water

is

added

This

to the chemical.

is

due

to the

tendency of

the desiccated salt to combine with water to form a crystalline compound.

This cake dissolves very slowly and

by pouring the

salt slowly into the

formation should be avoided

its

water while agitating the solution

vigorously.

30

UQ ^ \0

*v_y Fig.

7

â&#x20AC;&#x201D; Position

of eye

when judging

level

Another way of decreasing the caking

is

of liquid in a column.

to use chemicals

not too finely powdered, since the smaller the particle

size,

which are the greater

the caking tendency, especially with chemicals such as sulphite and car-

bonate.

now

So called granulated samples of

many

desiccated chemicals are

more quickly, have less tendency to float on the surface of the water, and are practically dustless when handled. The monohydrated variety of sodium carbonate, howavailable which pour easily, dissolve

ever, does not appear to

have any

less

tendency

to

cake than the desic-

cated variety.

As a general working rule, however, for all desiccated salts, the chemialways be added slowly to the water with stirring and not water to the chemical, or some caking trouble may be encountered. Equipment for stirring chemiMethods of Stirring Solutions. cal should

â&#x20AC;&#x201D;

cals

when mixing

as the mixing

solution

up

is

solutions

done:

to 100 or

i.

may

be classified into two types according

by hand

or 2.

by machinery.

200 gallons, hand mixing

is

For volumes of

usually employed, but


APPARATUS AND METHODS OF USE for larger volumes,

mechanical

more

stirrers are

efficient.

chanical stirrers also offer advantages for mixing volumes of

25

Small me2 5

gallons

or more.

The

simplest type of stirring device

either as a solid rod or as

Fig. 8

â&#x20AC;&#x201D; T> pes of hand A

sealed at both ends (see Fig. 8).

which

fits

is

a rod, preferably

heavy walled tubing (about

made

of glass,

| inch diameter)

stirring devices.

rubber hose or jacket (i inch long)

snugly around the end will usually prevent breakage of either

the rod or the vessel in which

used.

it is

A

stirring rod is only satisfac-

tory for use with very small volumes of solution, usually not greater

than

2

gallons.

If a glass

tube

is

chosen, a cork

may

be forced tightly

into the glass tube before sealing the ends in such a position that the

bottom of the cork

will serve as a

measure of volume when the rod is Additional volume calibra-

held upright in a particular mixing crock. tions

may

be made

in several

by choosing the length 2. by marking by putting more than one cork in the

ways as follows

:

i

.

of the cork so that both ends represent definite volumes,

the side of the cork with ink, or

3.


26

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

tube.

Too many

confusing.

A

calibrations should not be

made

become should be wedged

or they will

small card explaining the calibrations

into the tube.

For mixing volumes of solution from 8 in size, a useful

Fig. 9

to

40

liters (2 to

10 gallons)

mixing device consists of a metal rod (Monel, nickel,

â&#x20AC;&#x201D; Motion of paddle

for efficient agitation of deep nar-

row width

tank.

or Allegheny metal) with a metal disk fastened to one end (Fig. 8).

This

stirrer is

used

much

like the old-fashioned

hand churn by moving

up and down inside the mixing vessel. A wooden stick or paddle made of hard wood such as maple or cypress is a convenient form of stirrer for volumes up to 100 or 200 gallons (400 or 800 liters), but a separate paddle, marked with the name of the soluthe handle

tion,

should be used for each solution, to eliminate the possibility of con-

tamination.

Wooden

paddles should not be wax impregnated to resist

the action of the solution, because this treatment decreases their

resili-

ency and with hot solutions some of the wax is apt to melt and get into the solution. When the solution becomes cool, the wax particles, unless filtered out,

may

settle

on the surface of the

film.

The paddle shown second from the right in Figure 8 deep tanks by pushing it vertically down along one or crock,

is

used

in

narrow

side of the tank

moving it across the bottom by using the top edge of the vessel and drawing it upwards along the opposite side of the

as a fulcrum, vessel.

The paddle on

type which

is

the extreme right in Figure 8

used most effectively by thrusting

it

is

the conventional

vertically inside a


APPARATUS AND METHODS OF USE

27

tank along one wall and moving the blade through an arc by using the top edge of the tank as a fulcrum as shown in Figure 9. Considerable agitation may be secured with this type of paddle, providing the diameter of the tank

is

enough

large

to permit the

movement

of the paddle

through a fairly wide arc.

Fig. 10

â&#x20AC;&#x201D;-Portable

stirrer installed in a large

mixing tank.

Courtesy

M-G-M

Laboratories, Hollywood, Calif.

Notches cut

in the side of a

wooden paddle may

measuring a definite volume of solution

serve as a

in a particular

means

of

tank or crock by

holding the paddle vertically and adding water to the mark.

Mechanical Stirrers. types, namely, portable in

â&#x20AC;&#x201D; Mechanical

and stationary.

stirrers

two general is

supplied

a variety of sizes with telescoping metal shafts which, for photographic

solutions, should be stirrers

may

made

of nickel,

Monel, or 18-8

stainless steel.

The

be clamped onto the edge of the vessel or tank, as shown in

Figure 10, which represents an actual illustration

a large motion picture laboratory. is

are of

The former type

attached to the

stirrer.

in

a mixing room of

The motor

( 1/20 to 10 horse power) The blades are arranged to create an upward

current which insures thorough mixing, as shown in Figure iiA.

The two most common

types of stationary mechanical stirrers are the

mixing

tank

(Fig.

11 A)

and

1.

those

2.

those installed horizontally, through the side and near the base of the

installed

vertically

in


28

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

tank (Fig. iiB).

A

suitable stuffing

box

is

fitted at the point

where

the drive shaft enters the tank to prevent leakage.

In general, an electric motor should never be placed directly over a solution unless

it is

enclosed tightly, owing to the danger of contamina-

tion with oil from the

motor

shaft.

— Agitation

Fig. iia^

able vertical stirrer.

currents formed by port-

Courtesy Mixing Equipment

Co., Rochester, N. Y.

Theory

of Stirring/''

— Most

photographic chemicals are fairly

soluble in water at normal temperature and the majority are readily solu-

The method of stirring is not so imwhen mixing small volumes of solution, but it is of importance

ble in water at 125° F. (52°C.).

portant,

from the standpoint

of time saved, cost of labor,

when large volumes are The movement of the paddle

solution

to

and

clarity of the final

be mixed.

or stirring device

may

be considered

from several standpoints according to the nature and effectiveness of the motion produced. These different movements are as follows: * The authors are indebted for many Equipment Co., Rochester, N. Y.

of

tlie

ideas in this section to the

Mixing


APPARATUS AND METHODS OF USE I.

Free Rotational.

stirring

movements.

— This ^

It is

one of the most

is

tical shafts

supported

sets of horizontal paddles as

Fig.

I

common

types of

usually effected with stirrers which have ver-

one or more

of stirrer tends to set

29

in the center of the

mixing tank and which have

shown

in

Figure 12.

This type

up one or more horizontally moving layers

IB

— Agitation

in the

currents set up by hori-

Courtesy Mixing Equipment Co.,

zontal stirrer.

Rochester, N. Y.

mixing vessel (according to the number of paddles) and rate of solution.

slow

If the solution contains an alkali of heavier density

than water, the solution

probably tend to be denser at the bottom

will

than at the top. 2.

effects a

Impeded Rotational.

— This movement

is

similar to the free ro-

around the side of the tank created by the uniform motion

tational except that there are baffles installed

which tend

to

break up the stratification

of horizontally

moving paddles.

cals results with a

tendency 3.

mixer of

More

this type,

rapid dissolution of the chemi-

but there

is still

a fairly strong

for separate layer formation.

Vortex Movement.

— When a propeller type

of stirrer

is

placed

near or in the center of a liquid column, the rotation tends to create a

downward time.

swirling motion which assumes a vortex shape in a very short

This stirring motion

is

useful

when

dissolving a light fluffy solid

on the surface, but a considerable quantity of air This latter feature is is introduced into the solution at the same time. photographic somany because objectionable in photographic practice

which tends

to float


2

PHOTOGRAPHIC CHE^HCALS AND SOLUTIONS lutions are oxidizable

by

Furthermore, the entrapped

air.

air

bubbles

tend to cling to film surfaces and produce airbell markings. 4.

â&#x20AC;&#x201D; Most

Controlled Directional Flow.

liquid or liquid-liquid solutions

is

effective

mixing of

solid-

secured by stirring devices which in-

sure a controlled directional flow of the liquid within the mixing vessel.

Fig.

Motor driven

1

Paddle

vertical

shaft.

stirrer.

This flowing motion should be largely vertical and of drive

the top. ler,

heaw

any

solid or liquid portion

Such motion

is

best secured with the aid of a rotating propel-

the blades of which thrust

tion.

The

entire

mix

in a vertical plane.

same shaft

if

in a

is

sufficient force to

from the bottom of the vessel to

downward

in

an angular off-center posi-

thereby turned over and over from bottom to top

Two

or

more propellers ma}' be employed on the

deep tank (4 to 8

feet)

but their action should not be

opposed or their efficiency will be reduced. are used, the bottom blade

is

unable to

lift

\Mien opposed propellers

materials of different densities


APPARATUS AND METHODS OF USE

31

from the tank bottom, because of the retarding downward current of the upper blade. Propellers of the type described are

shown

tached to a portable stirring device and

motor

Figure

fitted to a shaft entering the side of the tank.

preferred for almost

all

Fig. 15

The

1

1,

A and

if

B, at-

a gear drive

Type A

is

to

be

photographic mixing operations on a large scale.

â&#x20AC;&#x201D; Glass funnel

fitted

with

filter cloth.

position of the propeller in relation to the tank design

Xow,

tant.

in

this, in turn, to

the tank

best results are secured

is

is

impor-

considered to be di\ided into four quadrants,

when

the stirrer

is

attached to the wall and in-

own quadrant.

In very

clined so that the shaft will rotate within

its

large tanks of

installation should be used.

The

3000 gallon capacity, a side

shaft should enter the tank on a line parallel with but off the center

line to insure a controlled directional flow.

These types of

stirrers represent

more rapid mixing with which have

less

free rotational or

is

to

dust in

is

possible with mixers

impeded rotational motion.

â&#x20AC;&#x201D;

The purpose of filtering and clarifyremove suspended matter such as dirt caused by the presence of the chemicals used and also any residue or undissolved particles

Filtering and Clarifying. ing

compact mechanisms which insure

power outlay than

which might

settle

on the sensitive photographic material during de-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

32

Furthermore, while some solu-

velopment, and produce spots or stains.

and

tions are being exhausted, for example, certain developers

fixing

and and scum which should be removed

baths, they tend to accumulate a sludge consisting of by-products

foreign matter, such as gelatin, dirt,

from the solution several times during

its

in order to prevent the

life,

sediment from adhering to the emulsion surface and causing spots and stains.

Filtration

may

be defined as the act of separation of a solid from a

by passing

liquid brought about

through the

filter is

known

to clear

allowing the particles

them by

The

etc.

liquid

which passes

as the filtrate, whereas the solid remaining

Clarification

in the filter is called the residue or filter cake.

term meaning

medium

the liquid through a filtering

such as cloth, paper, charcoal, sawdust,

a broader

is

up a suspension or cloudiness in a solution by to settle out by sedimentation, or by removing

In photographic work, the purpose of filtering

filtration.

is

usually to remove a small quantity of solid from a large volume of liquid.

The

filtration of

water to be used for mixing photographic solutions

represents a specialized application of filtration and

is

discussed in

Chapter VI, page 107.

The removal

of particles

remaining

in a solution after

may

mixing

be

accomplished by any of the following methods: A. Allow the solution to stand and draw pernatant liquid.

pended matter

is

This method so fine that

it

is

off or

decant the clear su-

particularly useful

will pass

when

through a coarse

the sus-

filter.

Since coarse particles settle quickly, the rate of settling of a semicolloidal sludge

can usually be hastened by mixing the solution

in

hot

water, because the heat tends to coagulate the suspension and causes the particles to cluster together.

Thus

crystals of

if

sodium sulphide

which are brown from the presence of iron are dissolved

in

hot water

the colloidal iron sulphide coagulates and settles out rapidly leaving a perfectly colorless solution.

B. Filter the solution through fabric or (Fig. 13).

Filtering through paper

is

filter

continual dropping of the solution exposes oxidation.

It

is

usually sufficient to

paper held

in a funnel

usually a slow process and the

filter

it

to the air, thus causing

through very

fine cloth or

muslin suspended from the edge of a glass funnel or an enameled

New

pail.

washed thoroughly, otherwise the sizing matter in the fabric will be washed into the solution and settle out as a sludge. C. As a modification of method B, when mixing a quantity of solution in a tank, stretch a filter bag made of strong toweling cloth (28 mesh) cloth should be


APPARATUS AND METHODS OF USE

33

over the tank, place the chemicals in the bag (about 6 inches deep) and allow hot water to flow into

and the solution

it.

filtered at the

In this

same

way

used for each solution so as to eliminate

Fig. 14A

Fig. 14B

The method is

fitted

â&#x20AC;&#x201D; Frame support

over a wooden frame and

less steel

bag is

A

all risk

for filter bap:

â&#x20AC;&#x201D; Method of supporting

of supporting the

the chemicals are dissolved

time.

filter

is

separate bag should be of contamination.

on deep tank.

bag over top of deep tank.

shown

in

Figure 14A.

held in place by

means

The bag

of four stain-

bars passing through loops along the edges of the bag.

In the case of deep tanks, the wooden frame can be dispensed with


:

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

34

by adopting the arrangement shown in Figure 14B. The cloth bag 5 inches deep is supported by means of bars passing through seams along opposite edges of the bag, and in turn the bars are held in place either by means of two pieces of wood passing over the ends of the bars as shown, or by metal stirrups fitted to the sides of the tank. It is important, when filtering chemicals through a bag, to add only comparatively small quantities of the chemical to the bag at one time. about

Warm water bag

(about i25째F.) (52째C.) from a hose should be run into the

slow stream, and as the chemicals are dissolved, more of the

in a

solid should be added.

If too

much

solid

and

for caking with desiccated salts

is

added, there

this interferes

is

a tendency

with the rapid dis-

solving of the chemical.

Some substances

are so finely divided that they will pass through a

bag unless one

filter

of very fine

mesh

is

used.

This

is

true of most de-

veloping agents, which therefore should be dissolved separately in as small a volume as possible of water at i25째F. (52 째C.) and then the solution poured into the filter bag.

The

sulphite

and carbonate compo-

nents of a developer may, however, be mixed and filtered by the bag

method.

In preparing large volumes of stock solutions of single chemi-

cals such as

hypo

or carbonate the filter

bag plan

offers

a rapid and

thorough method. It

is

important that the bag used should be wide and not too deep,

otherwise

will dip into the solution

it

and the chemicals

will dissolve

very slowly.

D.

A

A and C

combination of methods

is

the best and most desirable

as follows

For quantities of solution up

to 5 gallons, filter

through a cloth into

a bottle or crock fitted with a side tube of hard rubber inserted through a soft

rubber stopper (see Fig. 79, page 196). In this way the fine parout but the drainage tube is sufficiently high so as not to

ticles settle

disturb the sediment.

Charles

^

has described a number of useful methods of dissolving

chemicals which involve the suspension principle.

As one scheme, he

suggests adding the solid chemicals to a perforated earthenware pot

(such as

is

sold for electroplaters' use)

entirely below the surface of the water. inside the pot so that the solution

is

and suspending

A

filter

filtered as

this

pot almost

cloth could be placed

soon as the chemicals are

dissolved.

For small scale plants, the solutions should be mixed 1

Brit. J. Phot. 71, 519 (1924).

in

separate


APPARATUS AND METHODS OF USE

35

wooden vats or stoneware crocks in the chemical room, where they can by settling before transferring the clear liquid to the darkroom.

clarify

A

simple device for developer clarification consists essentially of a

water pump, a trap, and a vacuum nozzle as shown

FiG.

â&#x20AC;&#x201D; Suction

15-

device

and de-

in Fig. 15

removal of developer tank

for

sludge.

scribed

by

Ives, Miller,

and Crabtree.-

to stand overnight or until clarified

moved by

inserting the

tice,

the bulk of

much

solution should be allowed

bottom

in the

re-

nozzle in the solution and moving

it

up the sludge. With practhe sludge may be withdrawn rapidly without removing

carefully along the

very

vacuum

The

and the sediment

bottom so as not

to stir

of the liquid developer.

In a recirculating system as used on automatic developing machines for

motion picture work (see Fig. 90, page 211),

the sludge

by

on the return or suction

inserting a filter line

filters

it is

from the machine

to the circulating tank.

as used in other chemical processes

rapid filtration (Figs.

In addition to the

possible to

remove

at some point in the system, for example,

may

Pressure

be necessary for

16A and 16B).

filtering

media described, several others are

avail-

ble as follows: 1.

Sawdust contained

in a perforated

bulky and inconvenient 2.

-

to

Several types of charcoal. J.

box or

vessel.

This

handle when replacing the

Soc. Mot. Pict. Eng. 17, 26 (July 1931).

is

rather

filter.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

36

form of powder or cakes.

3.

Silicious materials in the

4.

Fine wire and glass-cloth screens.

5.

Paper pulp,

Fig.

To

i6a-

etc.

Small plate pressure filter showing construction. Engineering Co., New York, N. Y.

date, few of these materials

Courtesy Alsop

have been used by the photographic

industry but some of them will undoubtedly find extensive use in the future.

In the filtration of a gelatinous precipitate, such as a silver chloride sludge, a simple working

filter

can be constructed economically by lining

wooden box with canvas (Fig. 17). The box should be about 8 inches wide, 2 feet deep, and 4 feet long, or, if smaller, of about the same proportions. Since the perforations weaken the strength of the sides, these should be held together preferably at each end by a perforated

several metal bolts of 18-8 stainless steel. filtration to

add some

silicious

powder

It is

necessary for efficient

to the solution to

be

filtered to

prevent the gelatinous sludge from plugging up the pores of the canvas.

Such filters

filter

(see

aids are obtainable from several companies manufacturing

Appendix, page 342).


APPARATUS AND METHODS OF USE When quired. large so

filtering a silver sulphide sludge,

37

a different type of box

The box should be a shallow one, about 6 inches deep and that the sludge, when settled, will represent a thin cake.

A

box should be perforated and lined with canvas.

filter

aid

is

is

re-

fairly

The

necessary

to prevent stoppage of the pores in the canvas.*

Fig. i6b

â&#x20AC;&#x201D; Detail

of plate pressure

filter

Alsop Engineering Co.,

One

useful type of mixing

and

showing construction. York, N. Y.

filtering

apparatus consists of an enamel

lined mixing tank fitted with a portable stirrer.

through a small gear is

pump

to a

connected to the storage tank.

pressure

forated metal screen cylinders separated

paper or

filter

cloth

(Fig. i8).

is

filter

is

placed.

forced through the sides

*

The authors are indebted embodied

in this section.

to

Mr. R.

is

connected

which, in turn,

consists of

by a wrapping

a pressure of about 25 pounds per square inch.

tions

filter

These three units

cylinder on which a tightly fitting cover

the base of the column and

This tank

compact pressure

The

Courtesy

New

fit

two per-

of either

filter

inside a metal

The

liquid enters

by the pump under

The pump may

also

S. Scott for several of the filtering sugges-


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

38

be operated independently of the in the

filter

(see list of filter manufacturers

Appendix, page 342 )

^ 00000 o o o * * 00*-* O o

*

*

» -

-i

»

A Fig. 17

Fig. 18

— Canvas lined

— Cylindrical pressure neering Co.,

wooden

filter

box.

Courtesy Alsop EngiYork, N. Y.

filter.

New

Apparatus Arrangement for Large Scale Mixing.

— For mo-

work or large photofinishing establishments, the chemical room should be situated on the floor above the developing room when-

tion picture

ever possible so that there

is

no chance of contamination of the develop-

ing and drying rooms with chemical dust, while the solutions

may

be


APPARATUS AND IMETHODS OF USE piped to the various rooms without the use of pumps. cal solutions directly

avoided because this settles as

it is

in

fixing

Mixing of chemitanks should be

the dirt

when mixing, and

the developing and

impossible to

filter

out

all

39

a sludge at the bottom of the tank (see Chapter

IX

further details on conveying solutions; also Chapter IV' on suitable terials for the construction of

for

ma-

apparatus).

GRAVITV rCElO

Fig. 19

â&#x20AC;&#x201D; Mixing

tanks using (A) gravity feed, and (B)

pump

feed to storage tank.

When the mixing room is located above the developing room, the may be fed by gravity from the mixing tanks through a cloth

tions

A

solufilter

Hgure 19. Most efficient filtering with a cloth filter is accomplished by using a cloth of sufficient size to permit of occasional movement of the cloth across the into the feed or circulating tank as

shown

in

of


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

40

top of the

system

is

box

filter

so as to expose a fresh filtering surface.

pump would need

a recirculating one, a

If the

to be used to return

In some laboratories, it is inconvenient room on the floor above the processing room and it on the same floor or the floor below (B in Fig. 19).

the solution to the feed tank. locate the mixing

placed either

Fig. 20

Removing Scum. scum usually

skimming

off

If solutions are not filtered

This scum consists of

with a towel or a skimmer

is

device.

after mixing, a

has been allowed to

rises to the surface after the solution

stand a few hours.

be skimmed

— Solution

to

fibers, dust, etc.,

made

and

it

should

of several thicknesses of

cheesecloth stretched on a wire frame (Fig. 20).

When

a fixing bath has been used for some time and

is

allowed to

stand undisturbed for a few days, any hydrogen sulphide gas which

may

be present in the atmosphere forms a metallic looking scum of silver sulphide at the surface of the liquid and on immersing the film, this attaches

itself to

the gelatin and remains even after washing

Before the solution

is

used, any such

(

scum should be removed

scum

Fig. 21).

carefully

with a sheet of blotting paper or by using a cheesecloth skimmer as described above.

Layout o£ Chemical Mixing Room. will

vary

— The chemical mixing room

in size according to the extent of the

requirements of the user.

For the commercial photographer with a small business, necessary to build a small cupboard such as is

of sufficient size

and capacity

is

to hold the

shown

done.

The scale

rests

is

The door

lowered when there

on a wooden base which

it

may

only be

Figure 22, which

dry and liquid chemicals,

the scales, bottles, and a few other accessories. section holding the small scale

in

slides

is

of the center

weighing to be

on two guides.


APPARATUS AND METHODS OF USE

41

In large laboratories, the chemical mixing and storage room

occupy considerable

floor

may

Dry chemicals

space (see Fig. 82, page 200).

are received in barrels, drums, and cans and liciuid chemicals in cans,

and carboys.

barrels,

room

These should usually be stored

a separate

in

closely adjoining the mixing room.

-^"J^^^V

Fig. 21

â&#x20AC;&#x201D; Spot on film caused by

silver sulphide

scum.

(200 x)

Waterproof Floors for Chemical Mixing Rooms and DarkThe floors of rooms where photographic chemicals and solu-

rooms/''

â&#x20AC;&#x201D;

tions are to be handled should be constructed of waterproof materials to

prevent chemical attack and to permit easy washing.

Existing floors

wood and concrete. Xo attempt should be made to lay a waterproof floor over another floor, however, unless the latter is in good condition. All boards of wooden

are usually of two types:

floors

should be solid and fastened securely

move, they

If the

in place.

break up the waterproofing.

will

boards can

Concrete floors must be

smooth and should show no signs of disintegration. There are four general types of waterproofing materials as A. hard rubber

tile

blocks;

B.

mastic

(applied

hot);

*

The authors

are indebted to the Engineering Dept. at the

many

follows:

asphalt-

The rubber

concrete (applied cold); and D. reinforced concrete.

Rochester, N. Y., for

C.

tile

Kodak Park Works,

suggestions incorporated in this section.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

42

to

wood only, the mastic and asphalt-concrete on wood or and the reinforced concrete on concrete. All laboratory floors should be equipped with a side curb and drain permit easy washing with a hose (see drain construction in Fig. 23).

A

false floor

is

usually laid on

concrete,

made

of cypress should be built over the

main

floor at

such

height as to facilitate easy access to deep tanks.

Fig. 22

The Use

of a Fabric

â&#x20AC;&#x201D; Chemical

Membrane.

cupboard.

â&#x20AC;&#x201D;

It is general practice

when

constructing any of the waterproof floors listed above to lay a fabric

membrane in pitch before the waterproof floor is laid. A pitch-saturated open mesh cotton fabric is recommended. Paper membranes crack easily

The

and are not as satisfactory clean dry surface should

point) with waterproofing pitch.

with strips of fabric, allowing a

mopped with hot

as cloth.

be mopped (beginning at the lowest The hot pitch should then be covered 2 -inch overlap. The edges should be

first

pitch before the seams are overlapped.

layers of fabric should be applied over the first layer

should separate each layer.

Each ply

Two

additional

and a layer

of pitch

of fabric should be staggered


APPARATUS AND METHODS OF USE

43

about 24 inches from the hip of the previous hiyer. Fabric should not touch fabric at any point and no wrinkles should exist.

When

the third ply has been laid, the entire top should be

with hot pitch before

it is

covered with the specified

mopped

floor finish.

-3fc Wi°^' "•JT

"

SLOPE BOTH SUnrACCS TOWARD DRAIN V3 PLV WATER PROOriNQ MEMBRANE

^/ATtR PROOrcD

MEMBRANE SECURELY CLAMPED BETWEEN CLAMPINGi RINCa AND DRAIN. CLAMPINCi RIN& HAS SLOTS AT THE BOTTOM TO ALLOVrf WATER TO DRAIN OTF TOP OF MEMBRANE

NOTE: -^ TOP COURSE l» PLACED MONOLITHIC WITH XI' BASE

-5

\

COURSE Fig. 23

— Detail

of waterproof concrete floor construction showing arrangement of tank support and drain.

The membrane should be

carried

up 4 inches on

walls above the top of the finished floor.

the floor (see

D below)

A

all

pipe sleeves and

cove built monolithic with

should protect the membrane on the walls.

When

the fabric and cove are constructed against an existing plastered wall, the plaster is first removed to a point 3 inches above the top of the cove and then replaced to rest on the cove. Details on the various methods of waterproofing are as follows: Hard rubber tile may be A. Hard Rubber Tile Over Wood. laid down with waterproof cement on the waterproof fabric membrane.

If

much weight

tiles

is

to be placed

should be fairly thick,

-^-

to

on the i

floors,

at the corners.

B. Mastic Over

Wood

from trucks or tanks, the

inch, because the thin tiles will break

or Cement.

— !Mastic

sand, pea stone and fluxed asphalt mixture and

is

consists of a silica

obtainable from con-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

44

tractor supply houses.

It is

applied hot and,

when cool, varies in hardThe most waterproof

ness according to the ratio of sand to asphalt. floor

secured with a small proportion of sand.

is

not be used, however,

warm

weather.

if it is

Mastic

much

to receive

floors

which

will

traffic

Such a

should

floor

because

it

softens in

be walked on considerably

The surface will crack, The mastic should preferably be laid over a

should have more sand in proportion to asphalt.

however,

if it is

too hard.

waterproof fabric as described previously. All tanks should be supported on concrete blocks or curbing covered

over with a piece of sheet lead. sides until

it

The

laps over the mastic.

lead should be bent

No

down over

the

supports should rest directly on

the mastic floor or they will gradually sink through the mastic and cause leaks.

Wood

Asphalt-Concrete Flooring Over

C.

or Concrete.

â&#x20AC;&#x201D;

This consists of a mixture of cement, sand, emulsified asphalt, and pea stone.

It is laid

^ to

i

inch thick on top of the three-ply asphalt satu-

wood

rated waterproofing fabric placed over the

or concrete

and provides

a somewhat harder surface than the hot mastic type.

D. Waterproof Concrete Floor Finish for Concrete Floors.

â&#x20AC;&#x201D; Where new

waterproof conditions are desired for large laboratories or

buildings, a reinforced concrete finish, 23 inches thick, should be laid

on the waterproofed fabric membrane (see previous description, page 42).

Special brass floor drains with clamping rings should be used,

which

in addition to draining

off

water from the

any water which reaches the top

The

concrete finish that

soft.

The lower

and

is

layer

mixed as

is

is

constructed in

layers laid

the upper layer should be poured while the

lithic,

is,

floor finish will also drain

membrane. the form of two

of the

layer containing a welded steel fabric i

layer

first

is i

monois still

j inches thick

part cement and 3 parts standard concrete.

This

divided into sections of about 10 feet square, or smaller, and

the sections are separated from each other

by the use

of strips of elastite,*

or similar asphalt impregnated material, \ inch thick.

The

top layer

is

laid f inch thick

and

is

composed

of

i

part cement

sand (uniformly graded), with 3.5 gallons of water per bag of cement. This top layer is spread, tamped, screeded, and to 3.1 parts silica

leveled,

and then treated with a heavy power

float.

The

joints in the top

layer are ^ inch wide and are constructed directly over those in the

lower layer by the use of an edging tool for this purpose. *

Manufactured by Phillip-Carey

mason supply

dealers.

Co.,

Cincinnati,

Ohio,

After the

and obtainable from


APPARATUS AND METHODS OF USE completed

finish

has been cured for ten days, the ^-inch joints are care-

compound.

fully filled with a plastic

Where extremely heavy would prevent the

tomary

them

to

45

finish

loads on the lloor are encountered, which

from assuming

its

proper shrinkage,

extend these foundations through the floor

finish

directly on the waterproofing cloth (see drawing).

it is

cus-

and

rest

Lighter loads

or smaller tank foundations are placed directly on top of the finished floor.

Useful suggestions on waterproofing of floors are contained phlet

No.

92, published

writers, 85

John

Fig. ^4

St.,

Nov.

New

15,

in

Pam-

1937 by the National Board of Under-

York, N. Y.

â&#x20AC;&#x201D; Alberene stone

sink

and

ledge.

Note rubber mat

on ledge and trough at back.

Finish of Walls, Benches and Sinks. mixing or processing room should be painted

â&#x20AC;&#x201D; The walls light

of a chemical

gray or green, or white

with a semi-gloss enamel paint which can be washed easily. tory wall paint walls since

it

is

Kodak Panchromatic Green,

especially for

reflects chiefly the light transmitted

by a

A

satisfac-

darkroom

series 3

Wratten

temporary walls of composition board are used for a developing room, they should be protected behind the tanks by strips of safelight.

If


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

46

asphalt roofing paper.

Several sheets

solutions will run to the floor

may

and not drip

be overlapped so that the

off

on the wall.

Permanent Koda-

walls should be painted with a chemically resistant paint such as

coat paint.

25

â&#x20AC;&#x201D;

Vitrolite ledge

Sinks should be

The

water.

sink

on Alberene stone

sink.

An

of

ample proportions and piped with hot and cold be of wood covered with lead sheeting (burned

hard glazed stoneware (Fig.

excellent covering for all stone surfaces, particularly

vessels are to be used, strip of this should

any stone ledges

right.

may

joints) or preferably of Alberene stone or

24).

Drying cabinet shown on

is

if

glass

ordinary black corrugated rubber matting.

be cut to

or tables

fit

A

the bottom of the sink and the tops of

where solutions are

to

be mixed or handled.

This scheme minimizes greatly the possibility of breakage and provides a surface that rosion.

A

may

be washed quickly, and which

is

not subject to cor-

trough leading into the sink and placed next to the wall at

the back of the working ledge as

shown

in

Figure 24 represents a useful

adjunct to the sink.

Bench tops where of

wood such

or left bare.

dry chemicals are

as hard maple,

and covered

to

be used are best constructed

either with battleship linoleum

In either case they should be treated with several coats of

a hard floor wax, rubbed

down

well,

and polished.

Although hard rubber

sheets have been utilized only to a limited extent to date for coverings


APPARATUS AND METHODS OF USE

47

chemical bench tops, they appear to possess satisfactory character-

for

istics for

such purposes.

The

sheets should be cut to

and cemented with a waterproof cement surface.

If

in close

fit

the bench top

contact with the table

chemical solutions are apt to be spilled on the bench, Alber-

ene stone, plate glass, or lead covered wood are satisfactory construction materials.

An

opal plate glass

known

as Vitrolite has been used to a

KEV A -MO AC C

-CUPBOARD

on- DRAWER SS-SNAP SWITCH

FO-TLOOR C3RAIN W-^VATER OW-Ot5Tli,UED WATER

MW-HOT WATER OMW-OISTILLEO HOT WATER IG- ILI-UMPNATING GAS

CA- COMPRESSED *IR SD-STORAGE DRAWER rOR DRY CHEMtCAl_S SO-STOCK DEVELOPER 0WH-01STIl_l_ED l_-

Fig. 26

â&#x20AC;&#x201D; Diagram

of a chemical mixing

SOV.

WATER HEATE

LIGHT

room.

and drain boards. It is easy to clean and ismost photographic solutions. A darktype of construction is shown in Figure 25.

limited extent for sink ledges

resistant to chemical attack of

room equipped with

this

Storage space should be provided for etc., its

and each

vessel or piece of

all

buckets, crocks, stirring rods,

equipment should be cleaned and put

in

place after using.

A

diagram of a chemical mixing room

weighing bench

and

sink.

is

is

shown

in

Figure 26.

The

located centrally and conveniently to the mixing bench

Storage drawers for bulk chemicals, such as sulphite and car-

bonate, are arranged under the weighing bench and bottles of developing agents, bromide, and alum, are placed on a shelf over the bench. solutions of developers

and

fixing baths are kept in

Stock

stoneware crocks

This mixing room would be the room. and portrait photographer or for a moderate size photofinishing plant. Acids should be placed on a shelf behind the sink. See also Figure 83, page 201 for a design of a chemical storage

and tanks on the

left side of

satisfactory for a commercial

,

and mixing room

A

in a

typical mixing

weekly

is

shown

in

moderate

size

room capable

photographic plant.

of handling several

hundred gallons

Note wooden

trays for holding

Figure 80, page 197.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

48

weighed chemicals and types of stoneware and wooden tanks

A

solutions.

mixing room

in a photofinishing plant is

for storing

shown

in

Figure

8i,page 199.

Wooden

barrels are used for mixing vessels, arranged in two rows,

The upper row

one row being on a level above the other. mixing and each unit

for

is

equipped with a mechanical

lower row represents storage tanks.

provided

is

The

stirrer.

Behind the upper row of barrels

is

a platform equipped with a large sink, weighing table, and storage bins Solutions are fed from the storage tanks to the defor dry chemicals. veloping machines and printing rooms on the floor below.

laboratory

is

A

large mixing

Chapter IX, Figure 82, page 200. Note the the mixing and storage tanks, each of which

illustrated in

sink located centrally to

feeds to the developing machines on the floor below.

Portable mechani-

cal stirrers are used.

Every chemical mixing room and darkroom should be well

A

1

ventilated.

0-inch propellor fan will handle about 300 cubic feet of air per

minute, and

is

large

enough

taining 4,000 cubic feet of

and greater

to give air.

adequate ventilation

Proper

in a

room concomfort

air circulation insures

efficiency of the occupants of a

darkroom.

General Hints on Cleanliness and Handling of Solutions. â&#x20AC;&#x201D; Whenever possible, all chemicals should be stored and solutions mixed in a separate room from the developing, printing, or drying rooms. Chemicals keep best when stored in a cool, dry place and all containers should be closed when not in use. â&#x20AC;˘

Chemical dust

may

arise

cans, barrels, kegs, etc.,

and ing.

3.

spilling of

2.

from the following sources: spilling of

i.

leakage from

dry chemicals during handling,

wet chemicals which subsequently crystallize on dry-

Such dust frequently gets into the ventilating system when

it

in-

variably produces spots on films and prints (see Fig. 5).

The

floor of the

mixing room should have a drain so that

flooded occasionally to

may

wash away any

have accumulated (Fig. 23).

kept scrupulously clean.

it

may

particles of chemical dust

be

which

Scales and mixing vessels should be

^Mixing vessels, measuring dishes, and stirring

paddles should be washed thoroughly at once after use. In the developing and printing rooms

handle the solutions with care.

A

fixing

it

is

even more important to

bath splashed on the

floor will

dry up and the hypo crystals formed, after being pulverized by persons walking 23). prints.

in the

room,

will get into the air

Particles of dust

and cause spots (Fig.

5,

page

on the negatives produce white spots on the

If prints are dried

on cheesecloth stretchers, the cloth should


APPARATUS AND :\IETHODS OF USE

49

be removed and washed regularly to avoid trouble from stains.

De-

velopers and fixing baths should be

skimmed each morning before use (see paragraph on page 40). The developing and printing room floors should be washed at least once a week by flooding with a hose if a drain is present or, if not, by mopping frequently. Deep tanks of wood or stoneware should be sterilized at intervals to kill

fungus growths as explained on page 265.

All bottles, crocks, jars, etc.,

which are used as storage containers

solutions should be labelled carefully. label

A

which

is

It

is

good practice

to lacquer

for

any

intended as a permanent legend of the vessel's contents.

satisfactory lacquer can be prepared

by dissolving

amyl

film scrap in

Zl

MAPLE TOP BENCH

STONEWARE. SINK

THICK

Ij^"

KEY A — 110 AC SS^-SNTAP SWITCH

SL-SArC U\GMT DR- DRAWER

A

C-CUPBOARO

a

|m

(t)l.

I

FS-FOOT SWITCH

4'!-

OH

W — WATER

I

I

HW— HOT WATER OR

Q-

DC-DRYING CUPBOARD I- ILLUMINATOR

FS

r^rt LINOLEUM toVEREDJ BENCH

1

R-RE.5ISTANCE: U-LlGiHT

SiL ^

Fig. 27

— Plan

of a small darkroom.

acetate until the solution has the consistency of molasses. solution should be covered

Layout of Darkroom.

when not

— A plan

This lacquer

in use.

darkroom suitable for is shown in Figure This design was adopted by the Photographic Chemistry Departof a typical

a professional photographer or an advanced amateur 27,

ment of

the

Kodak Research

Laboratories after

many

years of experience

and solutions are handled on one side of the room and printing on the other side. Figure 25 shows the view of one side of a room built according to the plan. The Vitrolite ledge represents an alternative material to the wood construction shown in the plan. with various plans.

Note the

All chemicals

The

location of safelights and the illuminator.

turned on with a foot switch.

which blows

air

The drying

downward through a

cabinet

cloth

heating by means of electric coils are possible.

is

filter.

A

latter

be

Several degrees of

vertical

movable

plate has been installed inside in order that the size of the drying

may

may

equipped with a fan

be varied, thereby controlling the velocity of the

baffle

chamber

air current.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

50

Figure 28 shows a view of the bench and cabinets on the opposite side

An exposure box is located at the end of the bench. This equipped with several diaphragms and a rheostat for controlling the

of the room. is

light.

It is

exposures

very convenient, and often important, to be able to duplicate

when

For

printing.

this purpose, the rheostat is included in

Darkroom exposure box, with the

lamp

circuit,

and a voltmeter

is

rheostat and voltmeter.

attached across the lamp terminals.

Fluctuations in line voltage result in serious changes in exposure

from

no

Voltages for printing should be a

The

;

a drop

100 volts will almost cut the intensity of the lamp in half.

to

little

below normal, say, 105 volts. darkroom is an important

installation of suitable safelights in a

Overhead safelights may be either of the direct or indirect style. Bench or sink safelights may be fastened permanently to the wall or arranged to be moved. The degree of safety of a safelight to a specified sensitive material may be determined by exposing the material for vari-

matter.

ous times at a

by covering a

known

distance from the safelight.

strip of film

This

is

accomplished

with a piece of cardboard and moving the card

along an inch or so after each exposure until the material has received several exposures.

The

material should then be developed for a standard

time and temperature, whereupon a record will be obtained from which the time of exposure that

is

safe

may

be determined.

Every darkroom should be well ventilated Refrigerating units of small size are cost,

and

it

now

(see details on

page 48).

available at a reasonable

should be possible to utilize such units for controlling the

temperature of the

air in

darkrooms.


:

CHAPTER

IV

MATERIALS FOR CONSTRUCTION OF PHOTOGRAPHIC PROCESSING APPARATUS* When

selecting a material for the construction of

any particular piece

of photographic processing apparatus, several factors should be con-

namely:

sidered, 1.

The

which

it

resistivity of the material to the

come

will

fairly satisfactory for

most corrosive liquid with

For example, a galvanized tank, while

in contact.

washing purposes,

is

very rapidly corroded and

therefore unsuitable for use with fixing baths. 2.

The

solution.

on the photographic properties of the

effect of the material

For instance, a developer solution

visibly unchanged, but on testing,

it

may

in

a brass tank

may

appear

fog emulsions badly, due to

the copper salts dissolved from the brass. 3.

The time during which

material.

If a

developer

ultimately soften and peel 4. 5.

for

The The

the solution will be in contact with the

stored in a japanned tank, the japan will

off.

cost of the material.

adaptability of the material for construction purposes.

example,

and the

is

is

entirely unsuitable for large tanks because of

difficulty of

Glass,

its fragility,

annealing such tanks.

There are three general classes of materials suitable

for the construc-

tion of photographic apparatus intended for use as containers for or to

be immersed

in

photographic solutions, namely:

coated metals, and non-metallic materials.

These

metallic materials,

may

be subclassified

as follows

A. Metallic materials: Unplated and plated metals; alloys. B. Coated metals:

Enameled

steel,

asphalt-coated metals and lac-

quered metals. C. Non-metallic

materials:

Glass,

impregnated fibrous materials,

wood, paraffined wood, porcelain and glazed earthenware, rubber, rubber composition, nitro-cellulose materials, slate and Alberene stone.

Metallic Materials. will resist corrosion *

â&#x20AC;&#x201D; No metal or

completely in

The experimental work reported

thors in conjunction with H. A. Hartt,

J.

in

all

alloy has yet been found which

photographic solutions, and

this chapter

it

was carried out by the au-

F. Ross, and L. E. Muehler.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

52

is

therefore necessary to restrict their use to specific purposes.

]Metanic

materials possess certain desirable properties, however, such as duc-

and general workability, that render them parthe manufacture of several types of photographic apparatus such as small tanks, racks, film hangers, clips and non-fragility

tility,

suitable

ticularly

for

reels.

In considering the suitability of a particular metal for construction purposes,

it is

very important to

know whether

a single metal or of two or more metals.

the article will be built of

In the former case only the

corrosive effect of the solution itself need be considered, whereas in

the latter case an electrical current flows between the two different metals, and

effect

its

must be considered

in

addition to the chemical

action.

In testing the resistivity of various metallic materials to chemical action,

it

2.

necessary to observe the effects obtained under two sets of

is

conditions:

i.

those in which only a single metal or alloy

those in which two or

more metals or

is

involved and

alloys are in contact with each

other and also with the photographic solutions.

The

Resistivity oÂŁ Single Metals in Photographic Solutions.

â&#x20AC;&#x201D; An extended

has been carried out to determine the

series of tests

tivity of a large

number

of metals

The experimental

solutions.

details of the

materials given in the following

to

are recorded in a paper

list,

resis-

common photographic tests made on most of the

and alloys

by the

authors.^

Metals: Aluminum, iron, lead nickel,

tin, zinc.

Plated Metals: Galvanized iron, tinned iron, lead-coated iron, chro-

mium,

and cadmium-plated brass. Xo. 136 (aluminum-magnesium-copper), Corronil

silver

Alloys: (nickel

Aterite

alloy).

G

Illium

Duralumin

(aluminum-magnesium-copper), Duriron,

(chromium-iron-nickel),

Monel, Niaco

(nickel alloy),

Inconel

(chromium-iron-nickel),

Xichrome (nickel-chromium),

(copper-zinc-nickel-iron), Nicolene

nickel silver

(nickel-copper), phosphor bronze

(copper-tin-phosphorus), solder (both high and low tin content), Rezistal

1

J. I.

steel

" Tlie

(chromium

steel),

Resistivity of Various Materials

Crabtree and G. E. Matthews.

Eng. Chcm.

stainless

steel*

(iS^c

chromium-S^c

Toward Photographic

Solutions " by

Brit. J. Phot. 70, 366, 3S5 (1923)

;

also Iiid.

&

666 (1923). * Stainless steels of 18â&#x20AC;&#x201D;8 composition and containing small percentages of otlier metals are supplied by several manufacturers in the United State under various trade names, such as Allegheny metal, Carpalloy 8, Enduro KA-2, Rezistal KA-2, USS 1

8-8, etc.

15,


MATERIALS FOR CONSTRUCTION

with varying carbon titanium, zirconium, selenium content),

nickel

type metal (lead-tin-antimony),

USS 18-8 Mo

molybdenum) and various stainless steels. Method of Testing Metal Samples. is contemplated, tests should be made of the

quantity is

53

is

A

fabricated.

essentially the

(chromium-nickel-iron-

a large scale installation

If

metallic material before

simple but effective test

same as used by the authors

any

the following which

is

studying the materials

in

listed above.

The

strip of the

mouth

a wide

page 286) fixing

A

.

bath

metal or alloy to be tested should be half immersed

bottle containing the developer

sample should also be placed

tests

should be

made both

F-5, Appendix, page 310) and in the

The

latter test is desirable to

to plate out

from a used

fixing bath.

with a clean, new, cork stopper. the severity of the test it

in the acid fixing bath.

in fresh acid fixing

same bath when

determine

there

if

The

in

(Formula D-19 Appendix,

bottle

is

bath

(

The

Formula

partially exhausted.

a tendency for silver

mouth should be

closed

Although a closed container increases

somewhat because

it

gives a stronger vapor phase,

has been found an effective method of measuring the resistivity of two

more materials (such as different samples of 18-8 stainless steel) which very nearly the same resistance to vapor attack. Duplicate tests should be made at room temperatures, 65° to yo'F. (18- to 2i°C.) and at no F. (43°C.) and should be continued for at least i month and or

offer

3 days respectively.

The

results at high temperatures should not be

regarded as conclusive but merely as an indication of the resistivity of the material.

Observations should be made frequently of the appearance of the

samples and the developer should be tested

for its fogging propensity

The

condition

of the metal samples should be noted both above and below the

air line of

by

developing therein a strip of film for a

the solution.

The

normal time.

results of these tests give a fairly reliable indication

of the effective resistivity of the metal or alloy.

The Resistivity of Two or More Metals in When two Towards Photographic Solutions.

placed in contact and immersed in a solution, an

formed which causes more or metals. metals,

This electrical action

when some

less

may

Metallic Contact different metals are

electrolytic battery

is

rapid disintegration of one of the

occur

in several

ways; with plated

of the plating wears off; with soldered metals, be-

tween the solder and the metal; and with of the various metals which

compose the

alloys,

between the tiny crystals

alloy.

In making metal containers for photographic solutions,

it

is

often


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

54

necessary to use a second metal or alloy in the form of solder, to render the joints or seams free from leaks. lines for transporting solutions,

or fittings of the

trouble which

same material

may

it is

Also, in the construction of pipe

frequently not possible to use faucets

as the pipe line.

A specific example of

from the metallic contact

arise

in a solution

is

the

as

follows:

Fig. 29

â&#x20AC;&#x201D; Spotted

type of corrosion of copper-nickel

alloy after prolonged

immersion

in acid fixing bath.

In the course of a series of tests on metal tanks of a copper-nickel alloy, soldered if

on the inside with a lead-tin solder,

it

was observed that

a developing solution remained in the tank for a short time the de-

veloper gave very bad fog.

The

solder with which the seams of the tank

were soldered appeared to be etched slightly and the original luster of the metal

The

had disappeared and was replaced by a dark, grainy deposit. was unaffected as far as could be detected from its

alloy itself

physical appearance.

A

series of tests definitely

proved that

this ex-

was a result of the tin constituent of the solder passing into solution, due to the flow of an electric current through the solder, the When the joints were soldered on the outsolution and the alloy. side, no developer fog was produced and corrosion was considerably

cessive fog

less.


-

FOR CONSTRUCTION

:\IATERIALS

55

Corrosion was also observed due to the same cause when a tank

from

and soldered on the

this alloy

inside

was used as a container

made an

for

acid fixing bath, except that the alloy was corroded instead of the solder

The most

(Fig. 29).

above the air-liquid

shown

rapid corrosion of any metal tank usually occurs

An advanced

line.

in Figure 30.^,

case of air-line corrosion

is

which represents a portion of a rack made from

nickel-copper alloy which had been suspended in acid fixing bath for several months. .An extended study of this aspect of corrosion has been results are given completely in

made and

the

two papers.

Value of Various Metallic Materials.

â&#x20AC;&#x201D; Only

the practical ap-

plication of the results of tests on the various metals will be considered in this article; the original

papers should be consulted for more detailed

information.

Metals.

â&#x20AC;&#x201D; Lead

and nickel were the only metals tested which ap-

peared to be of any especial importance for use with photographic solualthough iron

tions,

of value for particular purposes.

is

and wrought iron tanks or piping can be used developing solutions although lead veloper.

Iron

is

attacked more or

form oxides and hydroxides filter

is

most

attacked by strongly alkaline de-

less

by most developers and tends

in the solution so that

Tanks

out such particles before use.

Lead, nickel

satisfactorily for

it

is

to

important to

lined with lead or nickel can

be used for fixing solutions but they are slowly attacked, become coated with silver and must eventually be replaced.

Plated Metals.

â&#x20AC;&#x201D; Galvanized

facture of washing tanks although of apparatus.

Vessels

made

iron has long been used for the it is

manu-

not entirely suitable for this type

of this material

must not be used, however,

mixing developers which contain sodium bisulphite, because the bisulphite attacks the zinc coating, forming sodium hydrosulphite which for

causes fog.^

Xickel-plated brass

is

are used intermittently.

satisfactory for small developing tanks which

Metals plated with

from an exhausted fixing bath or by

by deposition more resistant to

silver, either

electroplating, are

~ " The Effect of Electrolysis on the Rate of Corrosion of Metals in Photographic Eng. Chcm. Solutions " by J. I. Crabtree, H. .\. Hartt, and G. E. Matthews. Ind.

&

16, 13 (1924)

and

" Corrosion of

Crabtree and G. E. Matthews.

Monel Metal in Photographic Solutions" by Ind. & Chcm. i6, 671 (1924).

J.

1.

Contact with 3 " The Fogging Properties of Developing Solutions Stored in Various Metals and Alloys " by J. F. Ross and J. I. Crabtree. Aiucr. Phot. 23. 254 (1929).


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

56

developing solutions according to the homogeneity of the silver coating,

but their resistance towards fixing baths that of the unplated metals.

do not satisfactorily

resist

is

only slightly greater than

Aluminum- and cadmium-coated metals

photographic solutions.

metals would probably be satisfactory

if

Chromium-plated

were possible

it

to secure a

continuous nonporous coating over the base metal, but no such coatings are available to date.

washing tanks

if

Lead-coated iron can be used for developing and

the iron base-metal

is

not exposed, but

is

not very

satisfactory.

Plated metals and alloys are always open to the objection that as soon as

some

of the plating wears

electrolytic corrosion sets in,

Alloys.

â&#x20AC;&#x201D; Of

off,

exposing the other metal underneath,

and disintegration takes place rapidly.

numerous known alloys, Monel metal and 18-8 which have been adopted to any great photographic use. ]Monel metal is attacked and coated with the

stainless steel are the only ones

extent for silver

when used

for

storing exhausted fixing solutions.

Inconel, a

nickel-chromium alloy, appears somewhat more promising than Monel because tures.

does not plate out silver except very slowly at high tempera-

it

A

chromium-iron-nickel alloy

known

as Illium

B

also appears

promising.

Most samples

of 18-8 stainless steels are quite resistant to both de-

veloping and fixing solutions but some show a tendency to form corrosion pits above the air-solution line with acid fixing baths (Fig. 30B).

A

stabilized

form of 18-8

of titanium represents

stainless steel containing a small percentage

an improvement over the older 18-8

pecially for tank construction

provement

of the

18-8

where welds are required.

is

4%)

of

steels, es-

further im-

steels relative to their corrosion resistance to

acid fixing baths has been realized (2 to

A

molybdenum.

somewhat higher (25

to

The

by adding

to

them a small percentage

relative cost of such steels, however,

50%)

than regular 18-8 stainless

steel.

Another form that has high corrosion resistance contains a greater chro-

mium and

nickel content

advantage that

The

it

â&#x20AC;&#x201D;

12% nickel) and has the more than the regular 18-8 steel.

(24% chromium

costs only slightly

selection of a stainless steel for a construction material in connection

with photographic equipment depends, therefore, upon the type of use the equipment will receive and the fabrication requirements necessary

when forming the equipment. The welding of stainless rosion

may

chapter.

steels

must be done carefully or

occur at the welded joints.

cor-

See discussion at end of this


MATERIALS FOR CONSTRUCTION

57

An idea of the variation in composition of stainless steels of the 18-8 may be gained from an examination of the following table compiled

type

by

Smith.''

TABLE

I

Percentage Composition Ranges of Various Types of

Enduro Stainless Steel Type


PHOTOGRAPHIC CHEAHCALS AND SOLUTIONS

58

^

r

Fig. 30A line

Corrosion above air on section of metal developer

v/.

\^^'

v.*^

M

l-ii:.

iS-S

,,oi;

corro-idii

Pittfii

stainless

steel

above

ot

air-

liquid level after several weeks' ex-

rack.

posure to the vapors of an acid bath at 90°F. (32 °C.).

fixing

Coated Metals.

— The

resistivity

of

metals which readily cor-

rode can be greatly increased by coating them with a more resistant

metal or non-metallic substance.

The

properties and applications of a

few such coated metals are described below.

Enameled trays

Steel. Enameled steel is extensively used for small and tanks, and has proven fairly satisfactory. When the under-

coating of steel

is

vitreous enamel,

laid bare

it

by the chipping away

of the relatively brittle

corrodes very rapidly, and the vessel

is

rendered use-

Smooth, hard enamel coatings are resistant to weak acids used in photographic practice, but with developers and alkaline solutions the surface becomes etched, making it difficult to clean. Dye solutions

less.

permanently discolor such roughened surfaces of enamel. Glass Enameled Steel. Equipment having very satisfactory

re-


MATERIALS FOR CONSTRUCTION sistance to

velopers)

is

most photographic solutions (except strongly alkaline deavailable in the form of mixing tanks and agitators (5-gallon

upwards) suitable

made by

59

for

motion picture laboratory

use.

Such equipment

is

fusing resistive silicate enamels onto substantial steel shells at a

temperature of 980 ""C. (i8oo°F.).

Advantages claimed are less weight and bulk and greater heat conductivity than with cast metals or earthenware.

The

glass

enamel on the

than ordinary enamel since

steel

is

much more

resistant to breakage

Repairs

actually fused onto the metal.

it is

the event of breakage, however, are difficult to

make without

in

returning

the entire unit to the factory.

Lacquered and Painted Metals.

â&#x20AC;&#x201D;A

satisfactory photographic

lacquer consists of asphalt paint or a mixture of asphalt paint with rub-

ber cement, the latter serving to overcome the slight brittleness of the

Baked japan

asphalt coating.

is

very satisfactory, but none of these

materials will resist developing solutions containing a high percentage of alkali.

Freshly applied asphalt paint will often produce a scum on the

developer.

Kodacoat paint represents a satisfactory material metallic surface from corrosion

when subjected

graphic solutions or their vapors.

A

secure

maximum

tained

by using oxygenated

protection.

for protecting

a

intermittently to photo-

Several coats should be applied to

thicker protective coating

asphalt.

may

be ob-

This material requires melting

and must be applied hot for best results. Halogenated rubber paints such as Tornesit

*

and some other rubber

paints such as Pliolite f are also fairly resistant to the action of developers and fixing baths. Some types of bakelite lacquers, such as Larcoloid, t are quite resistant to the action of corrosive vapors.

As a general

rule,

it is

best to use paints

and lacquers on surfaces that

only receive intermittent exposure to solutions or their vapors because it is

it

very

difficult to treat

a surface with a paint or lacquer so as to render

completely impervious to the penetration of a liquid. It is

important to protect the exterior as well as the interior surfaces of

tanks to prevent corrosion of the base metal.

Consideration should be

given to the possibility of abrasion and pressure to which the exterior

may

A

heavy tank resting on a beam, for example, would soon press through any protective coating and allow surface

*

May

be subjected.

large

Products Co., Newark, N. Y.

Staten Island, N. Y.

& Lambert

t

Pratt

:

Larkin

Co., Buffalo,

Co., Buffalo,

N. Y.

N. Y.

Also Perry-Austen Manufacturing Co.,


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

60

corrosion of the base metal to occur.

All surfaces

which are

likely to

be abraded or worn away should be recoated at frequent intervals.

Laminated Metals. als

— About 1931, several types ^

of laminated met-

were introduced, which consisted of thin sheets of a corrosion-resistant

metal on a thicker metal base such as iron. steel, for

terials

Lead, nickel, and stainless

example, have been laminated onto

may

find

some uses

for

Such ma-

steel or iron.

photographic work but are open to the

objection that once the thin upper coating

is

broken through, the base

metal would probably corrode rapidly.

Non-Metallic Materials. in

— Several

satisfactory materials for use

handling photographic solutions on a large scale are to be found

in

the non-metallic group.

Glass.

— Glass

apparatus well annealed, free from

the corners of small trays and tanks rounded is

one of the most resistant materials available.

An

however, glass

is

opal plate glass,

and with

Owing

to its

not suitable for large trays and tanks.

known

as Vitrolite, represents a satisfactory

material for bench or table tops where chemicals are to be used. fairly resistant to it

may

most photographic solutions except strong

be kept clean easily.

Like other glasses,

and, therefore, care must be used that

it is

possibility of breakage of glassware

if

It is

alkalis

this material

and

brittle

is

not struck with a metal object.

A disadvantage common with stoneware or Alberene is the ever may

and

For the storage of

strong alkalis, special, resistant glass should be used. fragility,

ribs,

quite satisfactory

off, is

present

dropped on such surfaces.

This

be avoided by using a sheet of rubber matting on the surface where

glassware

is

to

be placed.

Impregnated Fibrous Materials.

— Trays or tanks prepared from

paper or other fibrous materials impregnated with varnish or lacquer develop cracks with use, thus permitting access of the solutions to the

under layers.

Such trays and tanks are entirely unsatisfactory

for use

with solutions containing strong alkalis, or with fixing baths, because these solutions disintegrate the fibrous materials through crystallization, as explained later under " Porcelain fiber trays carefully

tory for intermittent use

Containers

and Glazed Earthenware."

Small

impregnated with a high melting wax are satisfacif

carefully handled.

made from most laminated

phenolic condensation products

can be used with photographic solutions, with the exception of strong

Some samples of these materials have been found to and warp out of shape when used with strongly alkaline solutions.

oxidizing solutions. swell


INIATERIALS

Wood.

â&#x20AC;&#x201D; Wood

ing purposes,

and

FOR CONSTRUCTION

61

and wash-

fairly satisfactory for developing, fixing

is

cheaper than any other available material.

is

It

has

the disadvantage that, unless strongly braced, the tanks have a tendency

warp out

This tendency is at a minimum with round tanks, which should be well braced with iron rings that are tightened up as to

of shape.

I

Fig. 31

â&#x20AC;&#x201D; Splintering

of

wood

in a

hypo storage tank caused by wood.

crystallization

of the salt in the pores of the

much

as possible after the tank has been soaked thoroughly

with water and allowing If

it

by

filling

stand for several days.

used as containers for fixing baths, the tanks should preferably be

constructed of paraffined crystallize

on the

the tank

filled

many

as

wood

as described below.

sides, will penetrate the

splinter or crack as

In

to

shown

much

localities

in

Figure 31.

wood

in

Hypo,

if

allowed to

time and cause

it

to

This can be avoided by keeping

as possible.

fungus growths accumulate on the outside of the

washing tanks which must be removed frequently, while the inside of wash tanks often become coated with a layer of slime which necessitates frequent cleaning (see Chapter XII, page 265).

Wooden

containers

become permanently discolored if they are used for dye solutions. The most satisfactory varieties of wood for the construction of tanks are cypress, spruce, redwood, maple and teak. also


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

62

Paraffined

Wood.

— Although

woods such

certain

as cypress

and

teak are frequently used for the construction of containers for photo-

graphic solutions, paraffin-impregnated It also possesses the additional

wood

is

much more

advantage that

it

cumulate slimy layers as rapidly as unwaxed wood. advantage of paraffined wood

is

that

it is

satisfactory.

does not tend to ac-

The

chief dis-

too heavy for the construction

equipment which is to be handled manually. It is also quite and breaks easily if dropped. Methods of impregnating wood with paraffin have been investigated by Eberlin and Burgess, who found that the best results were obtained with cypress and spruce by soaking in of large

brittle

•"*

water for twelve hours, and then immersing

two hours at around

The soaking water

2

serves to swell the

in the pores

is

molten paraffin wax

in

for

50°F. (i20°C.).

wood and

in the

hot paraffin bath the

The wood should be wiped

replaced by paraffin.

thoroughly with a cloth on removing from the paraffin bath so as to

remove the excess wax.

made by grooving joint,

Watertight joints with paraffined wood are best

the pieces of

wood

to

be joined together, as for a T-

and inserting tightly a small piece

groove.

When

of unparaffined

caulks the seam.

Porcelain and Glazed Earthenware. ware, and

tile

wood

in the

placed in water the untreated strip swells and completely

— Porcelain, glazed

biscuit

material are usually unsatisfactory because the glaze in-

variably cracks, causing minute fissures into which the solution penetrates

and

The

crystallizes.

crystals then

grow and cause the biscuit Tanks of

ware to disintegrate, incidentally causing the glaze to chip.

high grade, dark brown earthenware, glazed on both sides, are especially

recommended

for storing ordinary developing

and hypo

solutions, but

should not be used with strong alkalis.

During 1933 a new form of hard glazed stoneware was introduced which was claimed to be free of all internal fissures, lighter and thinner than the older types of stoneware, but equally as strong and as chemically resistant.®

Rubber, Rubber Composition, Nitrocellulose and Asphaltum Materials.

— Pure hard

rubber will withstand practically

graphic solutions at normal temperatures.

5

"

Impregnating

Wood

with Paraffin " by L.

W.

all

photo-

Hard rubber thermoplastics Eberlin and A. M. Burgess,

Iiid.

& Eng. 6

40,

Chcm. 19, 87 (1927), Revised 1928. Ind. & Eng. Chcm. 25, Adv. Sec. 35 (Sept. 1933)

270 (May 1933)-

;

also

Chcm.

&

Met. Eng.


MATERIALS FOR CONSTRUCTION

63

(said to be sulphur free) were introduced in 1933/ These appear promising for the construction of small trays and tanks for photographic use.

For certain types of factory because

FiG. 32A

â&#x20AC;&#x201D; Hard

it is

hard rubber piping is very satisand may be threaded easily. Its chief disad-

installations,

light

rubber-lined steel tank showing; seam con-ti uction.

American Hard Rubber Co.,

vantage

is

its

brittleness.

New

Courtesv

York. N. Y.

Iron pipe lined with hard rubber, which

is

firmly cemented in the pipe, represents a very satisfactory type of piping

photographic solutions.

for

hard rubber pipe that

it

It possesses the

advantages over ordinary

does not require support every few feet and

is

not subject to breakage by impact.

Some

so-called hard rubber tanks are

made from a mixture

or rubber composition with an excess of mineral

somewhat

brittle,

warp under

filler.

of asphalt

Such tanks are

and when used as containers for same manner as porous earthenware.

heat,

salt solutions disintegrate in the

Smooth surfaces reduce the tendency

to etching since less strain

is

ex-

erted on the walls during the crystallization process.

Black hard rubber sheet or fabric-backed rubber sheet

may

be used

bench tops or sink ledges where photographic chemicals are to be handled. The sheets should be cemented to a wood table top with for

waterproof cement such as Plastikon cement, supplied by the B. F.

Goodrich Co., Akron, Ohio.

Rubber cements are now "

lud.

&

Eug. Chcm.

26,

available which produce a highly tenacious

123-129 (Feb. 1934)-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

64

bond between hard rubber and metal, wood, porcelain, and other surfaces, and which have fairly high resistance to corrosive attack of acids and

alkalis.

According to Fritz and Hoover

pounded

solutions of salts

Fig. 32B

immersion

to resist actual

and

Above 150'F. (65°C.) the

alkalis.

and

effects of

â&#x20AC;&#x201D; Hard rubber-lined

steel tank showing corner and edge construction. Courtesy American Hard Rubber Co., New York, X. Y.

oxidation, diffusion,

is

vulcanized rubber can be com-

for long periods in organic acids

and absorption become aggravated.

construction of soft and hard rubber it

-

is

described

by

A

three-ply

these authors which

claimed represents an improved type of material for coating the

surface of metal tanks.

The

and corner construction of two hard rubber-lined steel tanks 32A and Fig. 32B. Note method of filling corner with a triangular piece of rubber in Fig. 32 B, to produce a surface, which may is

joint

shown

in Fig.

be cleaned more easily.

These tanks are lined with a two-ply rubber

coating consisting of hard rubber bonded to soft rubber which, in turn, is

bonded

to the steel.

If the

made with overlapped seams

tanks are large enough,

as

all joints

can be

shown in Figure 3 2 A. With deep narmethod of assembly is used. They are

row tanks, however, a different usually formed as two shells with right angle bends at the edges where the joint is to be made. A soft rubber gasket is then set between the faces of the two shell edges as shown in Figure 32C and, when these faces 8

"

The Chemical Resistance

Fritz and J. R. Hoover. terials,

March

9,

of RulDljer as an Engineering Material " by H. E.

Reprint of Symposium on Rubber, Amer. Soc. Testing

1932, p. 79.

Ma-


MATERIALS FOR COXSTRUCTIOX are

drawn together with

occurs on the steel,

no

it is

bolts, the

tank

is

formed.

65

Whenever a corner

important that the weld be smoothed out so that

air pocket is formed when it is covered with rubber. Tanks may be constructed economically from steel

a thin

(^ inch) soft black rubber sheet

rubber

is

is

sheets on which

cemented intimately.

The

permitted to extend over the edges of the steel and " squeezed

joints " are

made

to

form the bottom and walls of the tank by bolting

Z

^^

^///////

t.

STEEL PLATE "^,

d \

SOFT RUBBER CASKET Fig. 32c

â&#x20AC;&#x201D;

Construction detail of joint in a rubber lined steel tank. Courtesy American Hard Rubber Co., New York, N. Y.

two opposite sides together and allowing the rubber sheets at the joint.

When

the bolts are

to protrude

drawn up, the two rubber

sheets are

pressed together and form solution-tight joints.

Rubber sheeting and rubberized cloth are often used for coating the wooden trays and troughs, and are very satisfactory provided

inside of

the surface

is

not subjected to

Cheap rubber sheeting

much

abrasion during use.

or tubing often contains an excess of free sul-

phur which reacts with photographic developers and causes chemical fog.^ Pure gum rubber materials are quite satisfactory. For handling long lengths of wide film (Cirkut film), a rubberized tray

is

e.xcellent.

Since solutions used in a tray or trough are usually in contact with the

rubber for only a relatively short time, more corrosive solutions can be used than 9

"

in the case of a rubber-lined tank.

Chemical Fog

"

by

J. I.

Crabtree.

Amcr. Ann. Phot.

33, 20 (1919)-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

66

A

flocculent precipitate

is

produced when some grades of soft rubber

are placed in a developer solution for several days. will

This precipitate

The use

tend to settle on film and produce scum markings.

of rub-

ber sheeting giving such precipitates should be avoided.

Rubber buckets such as the type made from Flexite) represent useful

FiG. 32D

dling of solutions

32D (which

is

containers for the intermittent han-

â&#x20AC;&#x201D; Rubber

bucket. Courtesy Goodrich Co., Akron, Ohio.

and are

tographic solutions.

illustrated in Figure

most pho-

resistant to the corrosive attack of

The handle should

preferably be

made

of stainless

steel.

Kodacoat paint

as mentioned on page 59 represents a satisfactory

material for coating wood, stone, and metal to protect them against the intermittent attack of acid or alkaline solutions.

A

may be applied with maximum protection.

It

a brush and several coats should be used to give

tarry material called oxygenated asphalt supplied

by the Stand-

ard Oil Co., has been found to be a satisfactory protective coating for use with

all

kinds of photographic solutions.

This material

while hot, as a thick coating over the metal or surface

is

is

if

is

applied,

a smooth

desired the coating can be smoothed out by the use of a blow

torch (Fig. 33).

weather

wood and

will

This coating

adhere to metal

is

normally somewhat tacky and

articles.

Therefore,

if

in

hot

a photofinishing tank

coated with this material, the upper edges of the tank should be pro-

vided with wooden supports for the metal rods carrying the hangers.


MATERIALS FOR CONSTRUCTION

67

Nitrocellulose lacquer (E. K. Lacquer

wooden

articles

No. 5119) is useful for coating such as racks for handling motion picture film, although

several coatings are usually necessary. nitrocellulose sheeting

A

aqueous solution."*

Fig. 33

â&#x20AC;&#x201D; Showing use

such material terial is

is

blow torch

to

Figure 34.

in

smooth out asphalt coating

Wooden

have also proved satisfactory.

that

it is

made from

small film developing reel and tank

of

shown

Small apparatus constructed of

satisfactory for use with almost every type of

is

very inflammable.

Slate and Alberene Stone.

A

in a tank.

tanks lined with this ma-

disadvantage of such sheeting

â&#x20AC;&#x201D; These materials are very

suitable for

For

constructing large tanks for containing developing solutions.

fix-

ing solutions, Alberene stone (a gray, finely crystalline variety of soapstone) splits

is

quite satisfactory, but slate

is

not recommended as

it

along planes of cleavage as a result of crystallization.

varieties of soapstone are not resistant to fixing baths,^^

disintegrate where the

sodium thiosulphate

often

Some

and tend

to

crystallizes out.

Develop-

above the

air-line of

ers also attack these varieties of soapstone chiefly

the solution and produce disintegration as indicated in Figure 35. 10 " Plastic Cellulose in Scientific

man,

Research " by K. Hickman and D. E. Hynd-

Frank. Inst. 207, 231 (1929). 11 " The Action of Hypo Solution on Stone Tanks " by D. Research, Xat. Bur. Standards 16, 161-164 (Feb. 1936). /.

'

'

W.

Kessler.

/.

of


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

68

A

satisfactory

cement

for joining large pieces of soapstone, as in con-

structing a tank, can be prepared from

i

part whiting,

2

parts litharge,

thoroughly mixed and made into a putty with boiled linseed ture of litharge and glycerine

is

recommended

for

oil.

A

mix-

cementing small

fit-

tings into the tanks.

Fig. 34

in

— Small

reel

and tank made from sheet

film base.

Oxygenated asphalt can sometimes be used effectively to repair cracks a soapstone sink. It has the advantage that it expands and contracts

slightly with changes in temperature.

Practical Suggestions Materials suitable for constructing various types of photographic apparatus are as follows:

Small Apparatus. (18-8)

is

(Clips,

film

hangers, etc.)

Stainless

one of the most satisfactory materials known, but

ommended

for use in toning solutions.

enced with film hangers made of

this

No

trouble

is

steel

not rec-

usually experi-

metal and having welded

cause such hangers receive only intermittent use.

is

joints, be-

Note: Stainless

steels

(18-8) containing small percentages of molybdenum (2-4%) are more resistant to corrosion than ordinary 18-8 stainless steel. Inconel and, to a less extent, nickel and Monel, have properties somewhat similar to those of 18-8 stainless steel.

Trays, Dishes and Small Tanks.

— Since

these containers are

generally used for a variety of purposes, they should be resistant to most

photographic solutions.

Suitable materials are glass, enameled steel,

hard rubber, teak wood or spruce impregnated with paraffin wax, wood, or metal coated with sheet rubber or rubberized cloth,

wood coated with


â&#x20AC;&#x201D;

MATERIALS FOR CONSTRUCTION

69

oxygenated asphalt, and well-glazed porcelain or stoneware. Plioform,* a rubber product that does not contain sulphur, represents a promising material for the manufacture of small trays and tanks. It is much more resilient than most types of hard rubber. Small amateur trays made of heavy cardboard impregnated with a high melting wax are fairly satis-

Disintegration of soapstonc tank above air-solution

FiG. 35

factory provided they do not receive rough treatment.

Monel, 18-8 stainless

steel (see note,

washing or developing, and

for

line.

Small tanks of

above), or Inconel are satisfactory

for fixing purposes

when

the tanks are

to be used intermittently.

Deep Tanks. finishing.)

â&#x20AC;&#x201D; (For

motion picture work and commercial photo-

Alberene stone, well-glazed stoneware and wood (cypress)

are suitable for developing and fixing baths.

Lead-lined wooden tanks

are fairly satisfactory for developing solutions provided the joints are

lead burned and not soldered.

Glass enameled steel tanks also are sat-

isfactory for use with developing solutions.

Iron tanks lined with hard rubber sheeting or, preferably, with soft rubber sheeting (sulphur-free) represent a useful type of container that *

Goodyear Tire & Rubber

Co.,

Akron, Ohio.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

70

is

resistant to corrosive attack (see Fig.

may

pansion joints

202) and

.

Overlapping ex-

be used with the hard rubber (see Fig. 84, page with soft rubber. The latter are produced

" squeeze joints "

by squeezing together

the rubber that protrudes over the edge of the

steel at the corner of the

An

32A and 32B)

tank by bolting opposite sides together.

economical method of constructing a tank consists in assembling

a rough form with slabs of slate or soapstone, treating these while

warm

with asphalt, and lining the form with sheets of double thickness window

warmed)

glass (also

It

.

is

important to cover the slate surfaces liberally

with asphalt.^-

wooden tanks are usually satisfactory but they tend to accumuStorage and circulating tanks made of cypress wood are used extensively in laboratories in Hollywood and New York (see Fig. 10, page 27). Tanks of paraffined wood can be used if the wood is properly joined together with strips of untreated wood as explained on page 62. Tanks of Portland cement have been found satisfactory for developers of low alkali content. Metal or wooden tanks coated with oxyPlain

late slime.

genated asphalt are excellent provided the base material

from chipping

Deep tanks

of the asphalt.

not exposed

is

of 18-8 stainless steel with

welded

joints have also proved satisfactory as containers for developers and wash water. Tanks for fixing baths should preferably be fabricated from 18-8 stainless steel containing 2-4% molybdenum, to prevent

from the acid vapors above the solution

pitting

page 205).

Covers for Tanks. namely: 2. dirt,

i.

grease,

made

in

for tanks serve several useful purposes,

they prevent too rapid oxidation of the solution by the air;

and other foreign matter are prevented from dropping

into the solution;

be

â&#x20AC;&#x201D; Covers

(see Fig. 85C,

level

and

3.

the rate of evaporation

two ways either

the solution.

;

to

fit

In the latter case, the solution

tection against oxidation.

is

may

Covers

reduced.

over the top of the tank, or to float on is

given the

maximum promay be

For small tanks, satisfactory covers

constructed of hard rubber or cypress

wood

or sheet celluloid.

It is

usually unnecessary to use floating covers for very small tanks since the

by adding

A piece of nitro-

volume can be maintained

easily

cellulose sheeting, in the

form of a shallow tray or boat,

floated

of 100 gallons or larger capacity, covers

wood about

joints (Fig. 36). 12

is

sometimes

on the solution.

For tanks pine

replenisher.

Tech.

News

6 inches wide

One

by | inch

may

be built of

thick and grooved with "

layer should be fitted together tightly

Bull. No. 246, Nat. Bur. Stand.,

T

"

and an-

Washington, D. C, 105 (Oct. 1937).


MATERIALS FOR CONSTRUCTION other cut to

fit

on the

first

layer at right angles.

71

The boards should be

screwed firmly together from one side with Monel or 18-8 stainless screws, counter-sunk below the surface.

The cover should then be

steel

given

No. 5119 is satisfactory), dry thoroughly before the next is ap-

several coats of a nitrocellulose lacquer (E. K.

and each application allowed If desired, the

plied.

cover

together by a shoulder joint.

Fig. 36

â&#x20AC;&#x201D; Large

to

may

be made in two parts which are fitted Most covers built of wood become badly

tank cover showing laminated con^-uucLiuii.

months of use but the degree of warping of the one described will be a minimum. For circulating systems, floating covers may be made of molded sheet celluloid or 18-8 stainless steel with the edges turned up slightly and the seams welded to form a shallow tray or

warped

boat.

may

after a few

A

be

fairly satisfactory cover for

made

tanks of 50 to 100 gallons capacity

of hard surfaced asbestos sheeting or Transite board.

Such

covers should be painted with an acid proof paint such as Kodacoat,

Probus, Tornesit, or Pliolite and the edges protected from chipping by

them with rubber edging as used around automobile windshields. may be held together by attaching a small strip of rubber at the points where the side strips meet. The most satisfactory cover for storage tanks of acid fixing bath and developers is one made from 18-8 fitting

Corners

Mo

stainless steel.

Floating covers

have been used

They

made

of sheet iron

for developer

and coated with oxygenated asphalt

supply tanks for large automatic machines.

are fairly satisfactory for such purposes but should not be used

with fixing baths or other solutions.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

72

Tubes, Sprockets and Idlers for Motion Picture Developing Machines. Hard rubber, lead, 18-8 and 18-8 Mo stainless steel, and Pyrex glass have been found satisfactory for developing tubes. Lead

gathers a deposit of silver from the fixing bath, and in time this tends to obstruct the tube, but this deposit can be removed by scraping.

Brass

or copper tubing should not be used since both materials affect devel-

The body

opers and are corroded by fixing baths. sprockets should preferably be

made

structed of Monel, Inconel, or 18-8

part of idlers and

of hard rubber with teeth con-

Mo

stainless steel.

should not be soldered with solders containing

tin.

Metal tubing

Seamless tubing

is

be preferred.

to

Bakelite impregnated fabric represents a useful material for sprock-

and

ets

idlers,

which are exposed

to the action of developers

baths.

Troughs

for Reel Development.

and

fixing

— Glazed stoneware and wooden

troughs lined with sheet rubber or rubberized cloth are satisfactory for practically all ordinary processing solutions.

Mo

stainless

steel,

Leads, nickel, and 18-8

Monel, and Inconel metals are satisfactory

for

use with developing solutions, and although they are slowly attacked

they

may

For acid oxidizing solutions or

be used with fixing solutions.

strong alkalis, hard glazed stoneware troughs are

emergency

if

recommended but the

Metal troughs may be used

troughs should be emptied after use.

the interior of the trough

is

lined with pure

gum

in

an

rubber

This latter lining is applied by coating the heavy canvas cloth and sticking it to the The cloth is then brushed metal with cumar resin (medium hard grade) over with molten hard paraffin wax and the surface finally smoothed off with a hot iron. The wax should be renewed at frequent intervals. Metal troughs may also be coated with oxygenated asphalt but great care should be taken to insure that the metal is covered completely and that the coating is free from bubbles. Japanned metal ware is only satsheeting or paraffined cloth.

interior of the trough with

.

isfactory for intermittent use.

Piping, Pumps, Faucets, Etc. lutions,

hard rubber, iron, Duriron, Inconel, and 18-8

piping and

pumps

steel faucets is

Hard rubber

should be used, especially

necessary.

Mo

For transporting

if

or 18-8

Mo

stainless

continual exposure to the solu-

fixing solutions,

hard rubber piping,

pumps are recommended (see also Chapter IX, page Gear pumps of hard rubber represent a simple and economical

valves and

so-

stainless steel

are satisfactory and should be used in connection

with faucets of similar materials.

tions

— For transporting developing

203). installa-


MATERIALS FOR CONSTRUCTION

73

when a flow not greater than 5 to 6 gallons per minute is required. Such gear pumps require priming and must be kept wet while running.

tion

For a more rapid flow, a centrifugal

pump

Tinned

should be installed.

or tin-lined, copper, or brass faucets or piping should be avoided for

use with developers or

fi,\ing solutions.

however, pipe lines and

fittings of

Pure aluminum piping

are satisfactory.

water

tilled

For conveying

lines.

tin solder

also satisfactory for dis-

is

has the advantage over

It

distilled water,

block tin soldered with pure

tin

and rubber that long

spans do not need supporting.

Lead piping dered.

joints should be "

apparatus

If silver-plated

wiped is

" or

lead-burned, and not sol-

used, the plating should be free

from pinholes or scratches.

A

suitable packing for

the aid of a

pumps consists of asbestos rope twisted with Hard rubber faucets, piping, etc., must

hard grease.

little

be protected from impacts or excessive pressure.

The

and 75 summarizes the above recommendations.

table on pages 74

Precautions to be Taken terials.

â&#x20AC;&#x201D;

I.

come

als to

Do

not permit

in contact

developers, because

When

tin,

Selecting Construction Ma-

copper, or alloys containing these met-

with developing solutions, especially concentrated

more or

less of the tin or

copper

will dissolve

and

cause either serious chemical fog or rapid oxidation of the developer.

Do

not use galvanized iron vessels to mix developing solutions contain-

ing sodium bisulphite because

sodium hydrosulphite

which

Likewise, the zinc in the inner coating

a bad fogging agent.

is

will

be formed,

of galvanized piping will cause developer fog.

Contact of two or more different metals or alloys exposed

to

a devel-

oper will hasten the rate of corrosion of the metal and thus increase the

amount

of fog obtained.

with developers, but

one

free

from

of solder 2.

is

tin

if

Soldered joints are particularly to be avoided

such joints are unavoidable, a low-tin solder or

should be used, and the joints so

made

that a

minimum

exposed to the solution.

^Maximum

corrosion resistance to developers and acid fixing baths

with stainless steel will be secured by using an 18-8 type containing

4%

2

to

or

when

molybdenum.

special fabrication

should be chosen

problem.

in

When maximum is

resistance

is

not required

needed, other types of 18-8 stainless steel

accordance with the individual conditions of the

Stainless steels with low carbon content (below 0.2 ^f)

containing small quantities of

molybdenum should be chosen

and

for con-

struction of tanks, trays, hangers, etc., that will be exposed to acid fixing


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

74

TABLE 3 CONSTRUCTION MATERIALS Solution

Developer

Storage Tanks

Wood

Pipe Lines Iron (ungalvanized)

(cypress)

Stainless steel *

Iron (ungalvanized)

Hard rubber Hard rubber-

Asphalt-coated wood Lead-lined

wood

Hard-glazed stoneGlass-enameled

Rubber-coated con-

Wood

Inconel

Nickel

ware

Hypo not

coated steel Stainless steel *

steel steel

Hard rubber

(cypress)

taining

Lead

Soft rubber

silver

Asphalt-coated wood

Lead

Hard-glazed stone-

Rubber-coated

ware

steel

Rubber-coated

steel

Glass-enameled

Stainless steel *

steel

Stainless steel *

Acid hypo

Wood

(cypress)

Hard rubber

containing

Asphalt-coated wood

Soft rubber

silver

Hard-glazed stoneware

Rubber-coated

Rubber-coated Glass-enameled

18-8

Mo

steel

steel steel

stainless

1

8-8

Mo stainless

steel *

steel *

Water

Same

as under

Developer

Distilled

*

Note

Block

Soft and hard rubber Stainless steel *

Block

tin

Aluminum

water

Galvanized iron

(pure)

tin

Aluminum

(pure)

These materials corrode under certain conditions of use with acid fixing Mo stainless steel is considered to be the most resistant. Refer to the discussion of stainless steels and other alloys on page 56. :

baths but 18-8


MATERIALS FOR CONSTRUCTION

75


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

76

Joints should be welded and heat treated,

baths.

if

necessary, accord-

Occlusions should be ground

ing to the manufacturer's instructions.

away from the back of the weld. The use of steels containing colombium and molybdenum is claimed to decrease corrosion by preventing segregation of carbon near the weld. 3.

For

fixing, toning,

ever possible. cloth 4.

and acid oxidizing solutions, avoid metals when-

Trays lined with pure

may be used for this purpose. When choosing metals for the

gum

rubber sheeting or paraffined

construction of apparatus, a single

metal should be used whenever possible, and

welded or soldered from the outside

Seams

in containers

made

to

it

should be either electro-

avoid electrolytic corrosion.

of sheet lead should be joined together

by

lead burning. 5.

Apparatus constructed

of

aluminum,

zinc, or galvanized iron should

not be used with either developers or fixing baths, since these metals react with such solutions with the formation of precipitates which leave

a deposit on the film and often stain the gelatin. zinc

wash tank

will usually

salts carried over

by the

A

galvanized iron or

corrode rapidly from the action of the silver

film or prints

from the acid

fixing bath.

Plated metals should be avoided whenever possible for use with

6.

photographic solutions and only single metals or alloys used

in prefer-

ence, since electrolytic corrosion sets in as soon as a little of the plating

wears 7.

off.

For fixing baths or strong saline solutions, avoid porous materials

such as incompletely glazed earthenware, impregnated fibrous materials, or rubber compositions, because crystallization of the salts within the

pores of the materials causes disintegration. 8.

Trays or tanks coated with lacquer or baked japan are not

re-

sistant to strongly alkaline developers or fixing baths of high acid con-

centration. 9.

Avoid the use of cheap rubber tubing or other materials contain-

ing free sulphur or metallic sulphides in connection with developing solutions,

because the alkali

in the

developer attacks these, forming alkaline

sulphides which cause chemical fog. 10.

Corrosion of stainless steels and other alloys will be minimized

greatly provided the surface of the alloy

is

cleaned at regular intervals.

â&#x20AC;&#x201D;

In constructing Notes on Welding Stainless Steel Tanks/'' tanks of the 18-8 molybdenum stainless steel, it is important that the * The authors are indebted to Eastman Kodak Co., Rochester, N.

tlie

Engineering and Maintenance Shops of the

Y., for the data supplied in this section.


.

MATERIALS FOR CONSTRUCTION material be furnished with a low carbon content. the carbon content be 0.08'

It

77

is

essential that

or less in order to inhibit the intergranular

,

corrosion which occurs at the joints of welded seams due to deposition of excess carbides

when

the welding heat

is

applied.

It

has been found

that with a carbon content of o.oSS' or under, this characteristic will be

controlled and there will be practically no excess carbides deposited

along the grain boundaries.

For tanks which are large enough to hold 50 to 100 gallons, stainless gauge thickness should be used. Where pos-

steel sheets of at least 16 sible,

corner welds should be avoided, particularly

inside of the tank are to be polished.

formed that the joints

sides should be so

the sheets on the

if

In other words, the bottoms and

come

will

inch or

i

.so

from

the corners so that the seams will be easier to grind and a straight butt

type of seam fully

a

may

be welded.

and where the tanks are

No. 2-B

Stainless steel sheets should be annealed to

be cleaned easily, should have at least

finish.

There are four commonly accepted methods of welding in

stainless steel

These are as follows:

commercial use today. O.xyacetylene method

1

3.

Carbon arc (electric method) Atomic hydrogen arc

4.

Metallic arc

2.

The

first

Use uncoated electrodes

]

Use coated electrodes

two methods are not recommended since there

carbon pick-up

For

this reason,

where the

ance value of the 18-8 molybdenum stainless

method

recommended. The use

is

of distortion and,

corrosion resist-

full

steel is to

arc with uncoated electrode will result in a very

mum

danger of

welded seam by the use of either the oxyacetylene

in the

or carbon arc method.

third or fourth

is

of the flat

on the whole, with very good

be realized, the

atomic hydrogen

seam with a miniresults.

It will

be

found, however, that there are comparatively few skilled operators for the atomic hydrogen arc welding method.

ably not be available

The tric

metallic arc

many

themselves.

That

will is

It

For

this reason,

it

will

prob-

locations.

method makes use

arc welding machines.

welding wire which

The

in

is

of the ordinary

commercial

elec-

well to specify the use of electrodes or

have the same approximate analysis as the sheets

to say, iS^r

chrome,

S'/r

nickel,

3%

electrodes should be coated so that full advantage

the protective gas which

is

released

by the use

molybdenum.

may

be taken of

of this type of electrode,


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

78

resulting in a

more

ductile weld

due

to the protection

oxidization of the deposited weld metal.

used with

work

all

types of metallic arc welding of stainless steel, that

or tank sheet should be the negative terminal

positive one.

mately

50%

from the rapid

Reversed polarity should be

The

co-efficient of

expansion of 18-8 alloys

greater than mild steel.

For

job for welding due allowance should be

is

for

the

approxi-

this reason, in setting

made

is,

and the electrode the

up the

expansion and contrac-

That is, greater care should be taken to use proper welding fixand clamps to prevent localized strains and distortion of the tank. After the weld has been made, it will be noticed that there is a discoloration along the sides of the weld seam. This is due to the scale which is formed at the high temperature of the welding arc. This scale and excess weld metal should be removed by grinding. tion.

tures


CHAPTER V

TEMPERATURE MEASUREMENT AND CONTROL The importance graphic solutions

of temperature in the preparation

by an increase

actions are accelerated tion

is

not always desirable since

A

reactions.

it

and use

of photo-

Most chemical

too frequently underestimated.

is

re-

temperature but such accelera-

in

may

result in undesirable

secondary

developer, for example, will require less time to produce

a certain density at 8o°F. (27°C.) than at 65°F. (i8°C.) but the solu-

much more

tion will also oxidize

a resulting increase in to

produce

with

Also,

fog.

film will swell

if

the temperature

and soften

The

difficulty.

rapidly at this higher temperature with

propensity to stain the gelatin of the film and

its

is

sufficiently high, the gelatin

such an extent that

to

it

can be handled only

use of suitable equipment for the control of tem-

perature represents an effective means for minimizing photographic troubles,

and devices

measurement and recording of

for the accurate

temperature constitute indispensable assets in the modern photographic plant.

Two thermometer Systems of Temperature Measurement. common use for measuring temperature, namely Centigrade

scales are in

and Fahrenheit.

On

the Centigrade scale (also called the Celsius) water

freezes at zero degrees

and

boils at ioo°,

and on the Fahrenheit

scale,

the corresponding readings are 32° and 212°.

Degrees Centigrade are

" °F."

Conversion of one scale

marked

" °C."

and degrees Fahrenheit

to the other should

be made as follows:

Since ioo°C.

= 2i2°F. — 32°F. or i8o°F.

i°C.=

and

°C. °F.

9/s°F.

X 9/5 + 32 = °F. -32°X 5/9 =°C.

In photographic practice, the Fahrenheit scale

employed, whereas

in research

work

in

is

almost universally

American and British univer-

and industries the Centigrade scale is used almost exclusively. For thermometers having unit scale divisions of equal width, the precision in reading a Fahrenheit scale is usually greater, since an error

sities

of 1° in reading the Centigrade scale

means an

error of nearly

2''

on

the Fahrenheit scale.

On

the continent of Europe, the

though most

thermometers are calibrated

in

Reaumur

scale

is

used extensively

al-

employ the Centigrade scale. Many both scales. The values on the Reaumur

scientific laboratories


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

80

scale differ

from the Centigrade values

scales

is

included in Chapter

50 °r

XIV, page

table

and Reaumur

347.

10°F

HVPROQumoNe Fig. 37

A

proportion 4:5.

in the

of comparative readings for the Fahrenheit, Centigrade,

— Comparative

ELON

rates of

development

of

Elon and hydroquinone de-

velopers at 50° and 7o°F.

Temperature

Effects

on

Photographic

Solutions.

chemical reactions proceed more rapidly as the temperature

and

than when cold.

w^ill

act

— Most

increased,

photography, so that

this is true of all the reactions involved in

developers and fixing baths

is

much more

rapidly

when warm

Different reactions are stimulated to different extents

by rise of temperature, and the effect of temperature can be measured numerically, the result obtained being termed the " temperature coefficient " of the reaction.

As a general

rule, the

temperature coefficient

is

measured

for a

change

of 10 degrees Centigrade, equivalent to 18 degrees Fahrenheit, so that


TEMPERATURE IMEASUREINIENT AND CONTROL if

a reaction, which at 60 degrees Fahrenheit takes 6 minutes,

at 78 degrees Fahrenheit in 3 minutes,

perature coefficient or factor of

we should say

that

is

81

completed

had a tem-

it

the rate of reaction being doubled

2,

for a rise of 18 degrees Fahrenheit.

The temperature

development varies with the develop-

coefficient of

ing agent, being least with the developers of high reduction potential,

such as Elon, and most with developers of low reduction potential, such

There

as hydroquinone.

is

one consequence of this which

is

rather im-

portant, namely, that the behavior of an Elon-hydroquinone developer

depends upon the temperature. is

very

inert,

At low temperature the hydroquinone is not decreased to the same

while the activity of the Elon

if it contained an At high temperatures the activity of the hydroquinone is increased far more than that of the Elon, and the situation is reversed. The difference in rate of development at low temperatures and at normal temperatures is shown in Figure 37. All four strips were given

extent and, consequently, the developer behaves as excess of Elon.

the

same exposure and equal times

It is seen that the lowering of

of development, namely, 4 minutes.

temperature has relatively

little effect

the rate of development of the Elon developer but slows

velopment rate of hydroquinone very greatly. that an Elon-hydroquinone developer will act

developer

A

if

the temperature

is

It is

down

obvious, therefore,

much

like

an all-Elon

lowered considerably.

similar principle applies to the fogging effect produced

opers.

If

development

ers will fog,

by

devel-

continued for a sufficient time, most develop-

but the fog reaction

and apparently has a

much

is

on

the de-

is

different

from that of development,

and one which

different temperature coefficient,

is

higher than the temperature coefficient of the development reac-

tion itself.

Consequently, a developer, which will develop an emulsion

to a satisfactory contrast with

low fog at a normal temperature,

produce very bad fog at the same image contrast

if

may

the temperature

is

high.

From in

the above

photography

is

it

will

be understood that the control of temperature

of great importance.

Whenever

possible,

development

always be carried out at a normal temperature (65째 If the temperature of the developer is too to 7o째F.) (18째 to 21째 C).

and

fixation should

high, then fog, softening,

and

Also, the solution oxidizes gelatin film.

The time

frilling of the

much more

of drying

On

is

material

readily,

may

also increased

by

the other hand,

if

too low, development will be delayed and there

is

cess water in the swollen film.

be encountered.

and tends

to stain the

virtue of the ex-

the temperature

is

danger of under-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

82

development, while the rate of fixation will be slow so that the fixing time must be prolonged to insure thorough fixation.

Acid fixing baths frequently decompose very rapidly with liberation of free sulphur

kept for a few hours to a few days at temperatures

if

over 95°F. (35°C.). temperatures,

it is

Although the rate of fixation

above 75 °F.

rise

for use

being 65° to 70°F. (18° to 2i°C.)-

rately

it

is

(2 4°C.), the

In storing large volumes

hypo and hardener solutions sepathe hypo when the latter is put into the

best to store the

and add the hardener

working tank.

increased at higher

recommended temperature range

bath to

of fixing bath

is

very bad practice to allow the temperature of a fixing

to

made

If cooling coils are used, they should be

of a

metallic material resistant to the corrosive action of these solutions (see

Chapter IV, page 52).

Some strongly oxidizing solutions, when employed at high temperatures

in particular acid

rapidly lose their effectiveness for

photographic use owing to secondary reactions.

work best

at temperatures

permanganate,

Usually these solutions

below 7o°F. (2i°C.).

Some photographic solutions, notably hypo-alum toning baths, are recommended to be used at 120° to 125 °F. (49° to 54°C.), but even these solutions should be watched carefully to see that the temperature

does not rise above that recommended. radation of the tone will result

if

Blistering, staining

and deg-

the temperature rises too high (above

i30°F.).

is

About the best general rule that can be given regarding temperature to mix, store and use the solutions at the temperature recommended

in the instructions of the

Types

of

manufacturer.

Thermometers and Their Application.

scale work, a good-grade glass fairly

— For small

thermometer of the usual type having

wide spaces between the unit divisions and legible figures

Some

satisfactory.

of these are

made

in the

form of a

Mercury

thereby serves a dual purpose (Fig. 38). of the best

known thermometric

liquids.

over a wide range of temperatures,

It

— 40*^^.

is

stirring rod is

quite

which

perhaps one

expands quite uniformly to -)-626°F.

(

— 40°C.

to

-f 330°C.). It is opaque, does not wet the glass, and has a relatively Ethyl alcohol has also large expansion for a given temperature rise.

been used extensively for measuring temperatures and other organic A dark liquids such as toluene have been used to a limited extent.

opaque liquid glass

is

preferable so that

it

may

be seen clearly through the

stem under darkroom illumination.

For the measurement of temperature of solutions automatic machines, the most satisfactory method

is

in

deep tanks or

to place a ther-


TEMPERATURE MEASUREMENT AND CONTROL mometer permanently

The method

in the tank.

of installation

is

83

impor-

tant.

For large storage or feed tanks which are provided with adequate

means

for stirring the solution, the

thermometer may be inserted through

the side, near the base of the tank.

Fic. 38

— Stirring

rod thermometer.

For working tanks or developing machines, practical to use the dial type of thermometer,

more convenient and

it is

which consists essentially

of a bulb, a long flexible stem, a flexible tube,

and an indicating

dial.

The bulb and stem may be placed in the tank from the top and immersed as much as desired, and should be made of a corrosion-resistant material such as 18-8 stainless

any

steel.

By

placing the bulb close to the tank wall

possibility of the bulb interfering with the

tank

is

obviated.

A

pure

gum

movement

used over the flexible tubing connecting the bulb and the

Three common types of thermometers are shown

A

has the scale attached to a short stem but

as type B,

which

is

fitted

of film in the

rubber or lead covered sleeve should be

is

Type

not as convenient to read

with a wall dial which

read at a glance from a distance of several

dial.

in Figure 39.

feet.

if

illuminated can be

Recording instruments

are also available which plot a record of temperature throughout the

day

(Fig. 39C).

For photographic work, an indicating thermometer

should have a large finger tapering sharply to a point.

The

dial figures

should be positioned so that a temperature of i8°C. (65°F.) cated

when the

finger

is

exactly vertical.

Any thermometer

is

indi-

reading less

than 2i2°F. (ioo°C.) which has a stem extending into or fastened to the inside of a tank should be withdrawn

when hot water

is

used to clean

out the tank, so as to avoid damage to the recording mechanism.

Methods

of Heating

Water

for

Mixing Solutions.

— Water

at


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

84

a temperature of

i25^F. (52°C.)

most chemicals, but there the chemicals

if

is

is

quite satisfactory for dissolving

a possible danger of decomposing some of

the temperature of the water

is

too high.

Most photo-

graphic chemicals are only slightly more soluble at i8o° to 2oo°F. (82°

— —

Stem type thermometer. Courtesy Taylor Instrument Co., Rochester, N. Y. Fig. 39B Dial type thermometer. Courtesy Foxboro Co., Foxboro, Mass. Fig. 39A

to

93°C.) than at i25°F. (52 °C.) and the slight saving

solution of the chemicals

is

and the extra time involved

Hot water

is

offset greatly

ture

is

in cooling the solution.

install their

argument against the use of water

own

heaters.

many

In such

at too high a tempera-

it is more economical i25°F. (52°C.) than to 180° to 20o°F. (82° to93°C.).

the increased cost of heating.

to heat water to

in time of dis-

possibility of spoilage

usually available from an independent source for

photographic workers but some must cases, a further

by the

Obviously,


MEASUREMENT AND CONTROL

TEIMPERATl'RE Hot water as follows: heater, 3.

i.

may

mixing solutions

for

85

be supplied from several sources

a water coil in the furnace,

an oil-burner operated heater,

a gas-flame operated water

2.

an

4.

and

electric heater,

5.

a

low pressure steam operated heater.

Fig.

A

â&#x20AC;&#x201D;

Recording thermometer. Courtesy 39c Taylor Instrument Co., Rochester, N. Y.

low pressure steam water heater consists of two essential units,

namely:

a. a

heating chamber and

ing chamber, in turn,

U

ing a group of " 2.

the head, as

is

is

as

fitted into the

chamber

Steam

It

in

The

is

filling

at the bottom.

the length of the

head.

A

The

a thermostatic control.

â&#x20AC;&#x201D;

i.

heat-

a chamber contain-

One end

Figure 40.

open end

sure of 3 to 15 pounds

three sections.

b.

of two parts

exit into

of the cylinder

is

open, and the head, to which are attached the water

the end of the head.

the

made up

shaped pipes having their entrance and

shown

closed, the other

pipes,

''

is

of the

chamber.

A

strong cap

fits

over

chamber under a presthe space around the pipes, and leaving admitted into the

A common

type of head

is

arranged in

incoming cold water enters one section, traverses

chamber twice and flows

into another section of the

then flows out again into the chamber, traverses

its

length

twice again and flows into the third section of the head, from whence flows out into the hot water pipe line.

it


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

86

At the point where the hot water leaves the head, a thermostat bulb This is connected by a capillary line to a valve on a 25- to 30-pound air line which operates the steam valve controlling the steam is

inserted.

pressure entering the heating chamber.

The

largest of the three gauges

STEIKM

Fig. 40

shown

in

— Diagram

Figure 40

is

set

at a desired temperature.

of a

by

low pressure steam water heater.

trial to

The two

operate the valve to deliver water

small gauges,

G^l

and Gg, measure the

pressure of the incoming air and the air which actually operates the

steam

A

line valve, respectively.

by-pass, B, should be provided as

shown

to operate the heater with-

out thermostatic control in the event that repairs are necessary on the

steam

line valve.

Control of Temperatures. \'ariations in temperature of plus or minus 2°F. are not usually important photographically except in the machine development of motion picture film or sensitometric control work. Variations of plus or minus 5°F. are usually serious, however, and in development must be compensated for by a change in the time of development or the image contrast will be affected. This is shown quite clearly in Figure 41,

which demonstrates the

effect of

changing the tem-

perature of a developer from 55° to 75° F. (13° to 24° C), on the con-

when developing for a constant time of 12 minutes. same developer (DK-50, page 288) it is interesting to note that equal contrasts at 55°, 65°, and 75°F. (13°, 18°, and 24°C.) are obtained in 14, 10, and 7 minutes, respectively. Therefore, when the trast of a negative

With

this

time of development

is

10 minutes, a change of temperature from 65°


TEMPERATURE MEASUREMENT AND CONTROL to

75°F. (i8° to 24°C.)

as

if

will result in

87

overdevelopment just as much

the time had been doubled at 65 °F.

The above

discussion serves to emphasize the need for temperature

control, especially in the case of large scale processing

55°F.

it is

often

75°F.

6s°F.

— Effect on contrast of varying the temperature

Fig. 41

when

of developer with con-

stant time of development.

difficult

offset

and sometimes impossible

temperature variations.

velopment in

in

many

to

change the time of development to

Furthermore, changing the time of de-

cases does not entirely compensate for the difference

temperature and at higher temperatures stains are apt to be produced. It is

a comparatively simple matter for the small scale worker to con-

trol the

temperature of his solutions by simply placing the bottle, tray,

or tank containing the working solution in a water bath of cold or

water until the solution has attained the desired temperature. scale work, the

problem becomes somewhat more

Water Mixers.

— The simplest type

of cold

warm

For large

difficult.

and hot water mixer

is

commonly used on household sink plumbing. It consists of a single By adjusting the valve on each line, water outlet fed by two lines. that

at

an intermediate temperature can be obtained.

Fluctuations in line

pressure and in the temperature of the water cause variations in tem-

perature of the mixed water, however, and

if

one of the

lines is

turned


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

88

off, it

permits the other to discharge without any mixing.

of this type

If

a mixer

used to control the water temperature flowing into a tray

is

or water bath containing films or prints, there

is

danger of ruining the

materials with extremely hot water.

42A - Water mixer with check valves on hot and cold Courtesy Fulton Sylphon Co., Knoxville, Tenn.

lines.

Several types of mixers are available which can be attached to the

hot and cold lines and which are not open to the above objections.

Some

of these mixers have been designed for shower bath installations in

Such mixers contain thermostatic

schools, hotels, athletic clubs, etc.

valves which contract or expand to maintain a constant delivery tem-

The Sylphon mixer

perature.

* illustrated in Figure 42A, for example,

uses a liquid expansion thermostat to control the cold water valve, and

a differential valve operated by the pressure change to control the hot

water valve.

In the event that either line

delivered

may

be

set

is

cut

off,

the mixer auto-

The temperature of the water to be by moving the hand lever on the side. Water

matically closes off the other

line.

mixers are supplied in several sizes and capacities according to the temperature requirements and the one illustrated will hold the discharged

water temperature within =t:2째F. of the

set point

with a supply water

temperature variation of 35째F. and a pressure variation of 30 pounds.

Another typical installation Valve (Series * Fulton t

R

is

the

Leonard Thermostatic Mixing

and T).t

Sylphon Leonard Rooke

Co., Knoxville,

Tenn.

Co., Inc., Providence, R.

I.


TEMPERATURE IMEASUREIMENT AND CONTROL The standard connections

for

any water mixer

installation are

89

shown

in Figure 42 B.

GAUGE GATE

^ 1 ^

VALVE

WOT ~^3ieg

.

1^4-

N

[><|

UNJION

CO\-D

WATER

r^^

^-^

— Standard

Fig. 42B

The mixing

STRAINER

^^^ifi^E*^

WATER TO MACHINE MIXER 65°^ OR TANK

pipe connections for water mixer installation.

valves described above are quite satisfactory for ordinary

use where the operating precision

not greater than

is

±2°F.

rate temperature

maintenance

is

In ex-

usually considered necessary.

treme cases the precision required

may

For

more accu-

processing laboratories using sensitometric control, however,

be as great as ±0.2 °F.

Under

such circumstances, more elaborate temperature control devices must

be installed, which compensate not only for pressure changes

in the lines

but also minimize greatly such factors as valve stem friction and hysteresis (friction

When

and

lost

motion) of diaphragms.

precise temperature control

ing equipment,

it

is

is

engineers of the leading firms

who manufacture temperature

equipment.*

Methods

of Cooling Solutions.

of cooling are

necessary on laboratory process-

suggested that the problem be discussed with the

by means

of

i.

— The

cold water,

regulation

three available

2. ice

and

methods

cooled brine or

3.

a gaseous refrigerant obtainable by mechanical refrigeration. I. Cold water is obtained from a faucet, by adding ice to water, or by mechanical refrigeration, and may be applied to the tanks in the following manner:

a.

Place pipes around the tanks.

b.

Place pipes inside the tanks.

c.

Place water jacket around the tanks.

d.

Flow water down

sides of tanks.

Placing the pipes around the outside of the tanks tory method, provided the tank material

is

as stoneware, Alberene stone, or metal.

With

or other poor conducting material, this

scheme

the rate of heat transfer *

See page 345.

list

is

rather slow and

is

a fairly satisfac-

a fairly good conductor, such insulating tanks of is

is inefficient

wood

In any case,

useless.

by virtue of heat

under water mixers and temperature regulators

in

Appendix

C,


90

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

transfer from the surrounding air, unless the pipes are enclosed with

insulating

medium such

Placing the pipes inside the tanks transfer but the pipes

Fig.

Lead

4,-i

must be

cuil

of a

is

a more efficient method of heat

non-contaminating material such as

un rack lor controlling temperature of a solution in a deep tank.

lead or 18-8 stainless steel for developers, and 18-8 less steel or

molybdenum stainThe dis-

hard rubber for acid rinse baths and fixing baths.

advantages of such a scheme are:

a.

the pipes reduce the available tank

space, h. in case of leakage the baths are ruined, fere with

an

as cork.

and

c.

the pipes inter-

keeping the tanks clean.

In the case of small tanks, the tanks which

may

300 gallon capacity sive floor load.

An

it is

feasible to place a water jacket

With

be of wood or stone.

this is usually impractical,

extremely simple method

around

large tanks of 200 to

on account of the exces-

is

to flow the

water down

the sides of the tanks through perforated pipes, but this will necessitate

frequent cleaning to remove the slime which otherwise accumulates on the tank walls.

In case the developer tanks are of stoneware or Alberene stone, a cooling tank It

may

be placed between the developing and fixing tanks.

should be equipped with a steam

in winter

and a brine

coil for

coil for cooling it in

heating the inflowing water

summer.

The

latter installa-


TEMPERATURE MEASUREISIENT AND CONTROL tion

may

be dispensed with

the temperature of the rinse water does

if

not rise above 65^F. (i8°C.) during the

cedure

is

is

surrounding

Cork

warm

insulation, although rather

The temperature

â&#x20AC;&#x201D; Arrangement

of a

quickly a few degrees

a lead

coil

for cooling solution in ice.

deep tank of solution

by using

the device

may

shown

attached to a wooden frame.

water faucet by means of a hose and the

the correct temperature.

of contamination

A

be raised or lowered

in

Figure 43.

It con-

The pipe is connected frame is moved about in

the tank for 5 or 10 minutes until the solution has

cause, unless the

from the

air to the tank.

deep tank with

to the

This pro-

also effective in preventing the transfer of heat

Fig. 44

sists of

summer months.

used successfully by some motion picture laboratories which

develop by the rack and tank system. expensive,

91

frame of stainless

become adjusted

steel

is

to

preferable be-

wooden rack is well lacquered, there is great danger by chemicals remaining in the rack after insufficient

washing.

With an adequate supply of cool water when using cooling coils, the temperature of the baths can be regulated automatically by means of a thermostat which controls the flow of water through the 2.

Ice can be applied by: a. placing

it

coils.

directly in the solution, h. plac-


PHOTOGRAPHIC CHEi\nCALS AND SOLUTIONS

92

ing it

it

in a

in

a rubber bag or metal tank inside the solutions, and

c.

placing

trough around the tank.

Although

ice is

frequently placed directly in the solutions,

tremely inadvisable because the melting ice dilutes the solution. ter method is to place the ice and move this around in the

in a

it

is

A

ex-

bet-

rubber bag or 18-8 stainless steel tank

solution.


TEMPERATURE MEASUREMENT AND CONTROL when very low temperatures

except is

are required.

93

In any case, dry ice

not recommended for cooling developing solutions because the carbon

dioxide gas converts

some

of the alkali in the developer to bicarbonate

and, therefore, tends to reduce the activity of the developer.

For rapid cooling, the dry placed

in a vessel

Fig. 46

â&#x20AC;&#x201D; Two

which,

ice

should be dissolved in alcohol and

in turn, is

placed

in the solution to

general types of refrigerating units.

be cooled.

Courtesy Frigidaire Corp.,

Dayton, Ohio.

Mechanical Refrigeration Methods. systems are readily applicable to

many

â&#x20AC;&#x201D; Mechanical

refrigeration

types of processing equipment.

Their use should be restricted, however, to the cooling of the actual solu-

because the cost of cooling wash water by this means

tions,

One type

prohibitiv^e.

essing (as described later) since

provides,

it

arrangement

is

usually

of installation designed for x-ray negative proc-

by means

for cooling the

may

be regarded an exception to the rule

of a novel supplementary cooling system,

an

working solutions as well as the wash water.

Fundamentals of Design of Mechanical Refrigerating Units.

â&#x20AC;&#x201D; Mechanical the fact that

pands freely,

it

it

becomes

amount

A a.

is

compressed

liquefied.

it

gives out heat

However,

On

if it is

compressed and cooled

allowing the liquid to evaporate

returns again to the gaseous condition but in doing so the gas

becomes cooled the

a gas

absorbs the heat again.

it

sufficiently,

depend on and when it ex-

refrigerating units of the compression type

if

to a

temperature below the surroundings, depending on

of liquid evaporated

and the rate of evaporation.

mechanical refrigerator consists of four component parts, namely:

the compression

pump

static control device,

and

or compressor, b. the condenser, d.

an expansion or evaporating

c.

a thermo-

coil.

Referring to Figure 45, the gas which may consist of sulphur dioxide, or a volatile organic compound is liquefied by compressing in

ammonia,


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

94

the compressor and cooled in the condenser either with an air fan or by

The Hquid

water.

refrigerant

is

then fed into the expansion

coil

through

the expansion valve which must be adjusted for each installation.

operation of the unit the material which coil as

may

On

being cooled.

is

The

be controlled by a thermostat bulb placed

in

evaporating in the expansion

a result of absorption of heat from the surroundings, the liquid

vaporizes and

is

returned to the compressor, thus completing the cycle.

A. Fig. 47

B.

— Direct-Flo cooling unit and section of

pipe showing construction. lor Co.,

Courtesy H.

W. Tay-

Warren, Ohio.

Refrigerating units

may

be obtained either with

cooled condensors as shown in Figure 46.

cooled or water

air

These units are available

in

several sizes which vary in accordance with the requirements of the user.

Refrigerating Equipment for Tanks o£ 40 Liters) Capacity.

made with

of tests

5 to 10

— In 1929 Wilsey described the

Gallons (20 to results of a series

a cooling unit designed for use in conjunction with

x-ray processing solutions

{X-Ray

Bull., E.

K. Co., 5; August 1929,

6: July 1930, page 6). The cooling unit consists essentially of two parts: A. a pre-cooler, and B. a Direct-Flo cooler. The

page

2; also ibid.

coils for

both coolers are made up of two lengths of metal tubing, one

scoped inside the other as shown

in

B

of Figure 47.

tele-

In the pre-cooler

the incoming water flows through the inner tubing and the cooled waste

water from the tank flows through the outer tube.

About two-thirds

the required temperature drop occurs in the pre-cooler.

The

of

partially

cooled water then flows into the outer section of the pipe in the Direct-

Flo cooler.

The

inner section of this pipe constitutes the expansion coil

of the refrigerating unit.

The

efficient

cascade system of washing

is

employed whereby the

water flows from one tank to another and the fresh water flows into the tank in which the films are placed

last.

A

typical installation of such


TEMPERATURE MEASUREMENT AND CONTROL a unit

is

shown

in

fixing tanks is

it is seen that the wash water flows compartment holding the developer and

Figure 48, where

from the wash tanks

fit

95

the

intt)

and then through the pre-cooler

supplied by the Halsey

W. Taylor

to waste.

Co.,

This entire out-

Warren, Ohio, who also

manufacture a compact pre-cooler and Direct-Flo unit illustrated at in

A

Figure 47.

simple thermostat

â&#x20AC;&#x201D; Diagram

\S

cooler.

A

used to control the temperature.

of cooling installation showing pre-cooler and Direct-Flo Courtesy Halsey W. Taylor Co., Warren, Ohio.

In cold weather, provision directly from

is

is

washing tanks

solution compartment.

made

to by-pass the flow of

to the drain

and

The temperature

waste water

to close the outlet

of the solutions

from the

then main-

is

tained by filling the solution compartment with water at the required

temperature.

Refrigerating Equipment for Deep Tanks as Used by PhotoMotion Picture Laboratories, Tanks of 10

â&#x20AC;&#x201D;

finishers or Small to

150 gallon (40 to 600

capacity are generally used

liters)

by photo-

and by motion picture laboratories which employ the rack and tank method of development. Such tanks are usually quite deep in profinishers

portion to their width and are adapted, therefore, to a system of cooling

which involves some scheme of applying a cooling

coil directly

against

the outside or inside of the tank.

A The

refrigerant liquid

may

may

be utilized

in several

ways

as

shown

in

Figure 49.

be circulated through pipes which are placed on the out-

side of the tanks as at

i.

or inside a

narrow tank containing water or a

mixture of w^ater and glycerine or alcohol to prevent freezing which, in turn,

is

placed in contact with the sides of the tank as at

ing tank

may

be immersed

in the

3. are satisfactory and give better heat transfer

2.

or the cool-

Methods 3. than method i.

tank of liquid as at

2.

and


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

96

tank containing the

If a

fixing bath, the

coils

is

actually immersed in the developer or

tank should be constructed of a corrosion resistant metal

preferably 18-8 stainless

and not soldered,

steel,

and should have the seams electro-welded between the solder and

to avoid electrolytic corrosion

the tank.

It is

3

z

I

Fig. 49

— Various methods of applying refrigeration

to deep tanks.

impractical to immerse the compressor coils directly in the tanks

because of the danger of local freezing or crystallization of the constituent chemicals.

An

actual installation on the principle of

The

uses 50 and 51.

30-gallon tank

is

method

i. is

shown

of stoneware | inch thick

in Fig-

and

is

with ^ inch copper coils (22 feet long), front and back, which are bent as indicated and welded or soldered to large copper sheets (20 ounces) held in position tightly against the sides of the tank by small fitted

wooden frames

or metal

bands (Fig. 50).

transfer from the surrounding air, the tank

In order to prevent heat

may

be completely encased

with 2-inch cork board panels or mastic-coated cork board allowing a I

-inch dead air space around the tank.

All exposed

wooden

parts, in-

cluding cork insulation, should be painted with a chemically resistant paint.

The

efficiency of this installation

the user. as follows:

may

be adjusted to

fit

the needs of

In a specific instance, the performance of an installation was

With

a

-^-

horsepower refrigerator unit

in

a room at 8o°F.

(26.5°C.) a freshly mixed developer in a 30-gallon tank at ioo°F. was cooled to 65°F. (i8°C.) in six hours and was easily maintained at this

temperature with a one degree variation. If the room temperature is above 8o°F., a greater time would be required to bring the solution temperature to 65°F. Also, if the initial solution temperature was less

than ioo°F., a proportionally shorter time would be required to adjust The current consumption for three such tanks, each cooled it to 65 °F.

by to

would be around two to room temperatures varying from 75°

refrigerating units of j horsepower capacity

three kilowatt hours per

90° F.

This

is

day

for

considered a satisfactory performance because this


TEINIPERATURE

MEASUREMENT AND CONTROL

97

temperature variation of one degree would not greatly affect the negative

work a more expensive and

contrast although for high precision

precise

thermostat should be installed.

â&#x20AC;&#x201D;

Fig.

50

â&#x20AC;&#x201D; Cooling tank.

installation

51 Cooling installation for Fig. deep tank. Detail showing thermostatic switch and expansion valve with connections to compressor.

for deep

General view.

must necessarily be considered a separate problem by the individual firm working in collaboration with the refrigeration company.* The above method of cooling is applicable only to stoneware or metal tanks which conduct heat fairly well wooden tanks, which have low heat

Each

installation

to be solved

;

conductance, should not be cooled in this way. essary

I

.

to

immerse the cooling

In such cases

it is

nec-

narrow water bath placed

coils in a

in-

and along one wall of the tank as shown in 3 of Figure 49, or 2. to run cool water through coils immersed in the tank, or 3. to circulate the developer as shown in Figure 52. This last named scheme is applicable As shown in the also to large tanks of 100 to 500 gallons capacity.

side

figure, the solution

is

circulated

by means

of a

rounded by a chamber containing refrigerating It is

assumed

in

connection with

all of

pump

through

coils sur-

coils.

these methods of refrigeration

that the solution will receive a normal

amount

* Equipment adapting the above principles Manufacturing Corp., Rochester, N. Y.

is

of agitation during use

supplied by Kellogg Compressor

&


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

98

such as

is

given by moving tilm hangers in and out of the tanks and

agitating the hangers at intervals during processing.

perienced with a temperature gradient, that

is,

If difficulty is ex-

a difference in tempera-

ture between various parts of the solution in the tank,

it

may

sary to install some type of stirrer to agitate the solution.

100 gallons or larger capacity utilized is

by means

is

of square shape

If

be necesa tank of

and external cooling

of coils applied to the tank walls, the use

is

of a stirrer

imperative or uneven temperatures will prevail in different parts of

the tank.

PUMP Fig. 52

REFRIGERATING UNIT

â&#x20AC;&#x201D; Method

of cooling large

tanks by circulating the developer through an external chill box.

Refrigeration Equipment for Use with Large Automatic Large Developing Machines of 100 to 500 Gallons Capacity.

â&#x20AC;&#x201D;

automatic processing machines are essentially of two types, as follows: 1.

machines using the continuous flow system

2.

machines using the recirculation system

for the solution feed,

for the solution feed.*

and

The

problem of temperature control with either type of machine requires some scheme whereby small fluctuations in temperature are quickly corrected.

Machinery

of this t5^e

is

usually installed in rooms which are

equipped with automatic temperature and humidity control of the ventilation system. Solutions are usually fed from the mixing tanks to the circulating or storage tanks *

and then

These systems are discussed more

to the machines.

fully in Chapter

portation of chemicals and solutions, page 210.

IX

The temperature on storage and trans-


TEMPERATURE MEASUREMENT AND CONTROL of the solution in the storage tank

from the temperature required temperature variations

may

is

99

seldom over a few degrees different

in the

machines.

affect negative quality

be given the problem of correcting for fluctuations

Nevertheless, slight

and attention should in

temperature.

In either of the two systems mentioned above, satisfactory cooling

be accomplished in two ways, namely:

may

by flowing cool water through a coil immersed in the storage tank, or />. by passing the solution through a coil surrounded by a refrigerating coil (as shown in Fig. 52) on its a.

passage from the circulating tank to the machine.

Methods of Raising the Temperature of Photographic Solu— The three most common sources of heat for raising the tem-

tions.

-

perature of a solution are:

i.

hot water,

steam, and

2.

3. electricity.

For small scale work, a water bath surrounding the tank or tray Electrical immersion heaters

effective.

schemes described previously

may

quite

is

also be used.

INIany of the

may

be utilized to

for cooling solutions

heat them by using water or steam coils installed in a similar manner.

Although

electric heating jackets

have not been employed to any extent

such heating arrangements should prove satisfactory

in the past,

in

use

providing the jackets are well heat-insulated and protected against the action of the solution. tive

means

ture

is

a

For large processing machines, the most

effec-

of preventing an undesirable drop in the solution tempera-

to recirculate the solution

chamber heated with steam or

and surround the pipe at one point with electrically heated coils.

Wash Water

Importance of

Temperature.

— When

washing

photographic materials, the temperature of the wash water should not

be too high or too low.

If

it is

too high, over i2o°F. (7,8°C.),

it

may

cause blisters to form in the gelatin layer, or softening of the emulsion.

A satisfactory temperature

range is65°to75°F.(i8°to24°C.).

Nega-

on film or plates) do not wash any more rapidly, by hypo elimination, in warm than cold water, but positive materials, coated on paper, wash more rapidly in warm than cold water because the hypo appears to be held less tenaciously by the paper fibers. tive materials (coated

as measured

when washing paper

Therefore, creased

if

prints, the

washing time should be

in-

the water temperature falls below 6s°F. (i8°C.).

Tropical Processing of Photographic Sensitized Materials.

— Where the temperature cannot be

controlled, as

may

be the case in

and plates provided special measures are taken. These involve the use of solutions which have a minimum propensity to swell the gelatin and which act rapidly so the tropics,

it is still

possible to develop films

that the film or plate needs to remain only a comparatively short time in the solutions (see

Chapter VIII, page 180).


:

CHAPTER

VI

EFFECT OF THE WATER SUPPLY ON PHOTOGRAPHIC SOLUTIONS Water

is

the most widely used chemical in the processing of photo-

graphic materials and ties

present in

impurities

it

may

may

important to

it is

know

to

what extent the impuri-

be harmful to the various operations and

how

these

be removed.

Impurities in Water. water from clean, melted

â&#x20AC;&#x201D; Excluding

ice or

distilled water, rain water,

snow, the following impurities

and

may

be

present

Dissolved salts such as bicarbonates, chlorides, and sulphates of

1.

calcium, magnesium, sodium, and potassium.

may

Suspended matter, which

2.

consist of:

a.

Mineral matter such as mud, iron

b.

Vegetable matter such as decayed vegetation, fungus growths,

rust, or free sulphur.

and micro-organisms.

The suspended

particles

may

be of colloidal dimensions

case they are difficult to remove

by

in

which

filtration.

Dissolved extracts, usually colored yellow or brown, from decayed

3.

vegetable matter and the bark of trees.

Dissolved gases such as

4.

air,

carbon dioxide, sulphur dioxide, and

hydrogen sulphide.

EFFECT OF IMPURITIES ON PROCESSING Development.

â&#x20AC;&#x201D;

containing calcium

cium

i.

If a

salts,

sulphite, but with

developing solution

is

prepared with water

a white precipitate consisting largely of cal-

some calcium carbonate,

is

apt to form on mix-

In some cases a precipitate does not form immediately but a

ing.

sludge

^

consisting of fine needle-shaped crystals of calcium sulphite sepa-

rate out on standing (Fig. 53).

Such a sludge or precipitate will settle However, the

out on the emulsion side of the film and cause spots.

harmless

white precipitate or sludge

is

clear supernatant liquid

drawn

is

if

allowed to

off for use.

settle,

Magnesium

and only the salts,

unless

present in excess, are not precipitated.

The

developer, of course,

is

robbed of sulphite and carbonate to the

extent required to form the sludge or precipitate, but except in the case 1

"The Nature

(igi8)

;

B.

J.

of a Developer Sludge" by

Phot. 65, 87 (1918).

J. I.

Crabtree.

Amcr. Phot.

12, 126


EFFECT OF THE WATER SUPPLY ON SOLUTIONS of developers of low alkalinity, this effect

have shown that calcium or magnesium need to be present

is

negligible.

salts

101

Experiments

(chlorides or sulphates)

concentration greater than o.i /c to produce an

in a

appreciable effect on the developing power of developers containing

0.3% sodium

carbonate.

% â&#x20AC;˘".S^iJ^,.... ;.^^ ^.y

W:0

.:.\\

'y^'i^c

â&#x20AC;&#x201D;

Fig. S3 Crystals of calcium sulphite precipitated from a developer pre-

pared with hard water. Artificially

hardened water was used

According

tests.

to

U.

in

preparing developers for the

Geological Survey data

S.

-

on the hardness of

natural waters in different parts of the United States, the hardest water tested

was found

0.04%

to contain only

of

permanent hardness (calcu-

Depression of negative contrast by virtue

lated as calcium carbonate).

of a lowering of the sulphite or carbonate content of a developer

with natural waters found

liable to occur, therefore,

with weakly alkaline developers.

e.xcept, possibly,

in the

is

not

United States

In the case of devel-

opers containing a low concentration of borax, which are very sensitive to slight

changes

of calcium salts

in alkalinity, the presence of

would be

sufficient to

an appreciable quantity

lower the alkali content, and due

allowance for this should be made.

The

precipitation of calcium carbonate can be prevented

sodium metaphosphate (NaPO..) on the hardness, but (30 grains per quart)

fixing

an excessive amount (over

if

apt to form on the film

to the water, in proportion

is

used, a precipitate of

when

bath unless the film

placing in the fixing bath.

is

it is

depending

grams per liter) aluminum phosphate is 2

transferred from the developer to the

rinsed thoroughly in running water before

The

addition of metaphosphate to a fixing

bath containing alum tends to destroy 2

by adding

its

hardening properties.

U. S. Geological Survey Water Supply Paper No. 496.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

102

Salts liable to be present, other than the above, are chlorides

mides of the

alkali metals

carbonate, which

the action of a weakly alkaline developer.

exert

to

any appreciable

With

in the

It is

if

the average developer,

water used for mixing

is

Developers mixed with

effect.

water containing sodium or potassium sulphides fog even

Sodium up

present in certain alkaline waters, tends to speed

is

however, the concentration of the alkali insufficient

and bro-

which exert a restraining action.

bad chemical

will give

the sulphides are present in very small quantities.

customary

to

add copper sulphate

riodic intervals in order to kill vegetable

the presence of

to certain

and

water supplies at pe-

biological growths.

While

part in 10,000 of the copper salt in a developer will

i

cause aerial fog,^ the concentration of the copper salt in the water supply usually 2.

a.

is

much

lower than

this.

Dirt and iron rust suspended in the developer solution often

produce spots and

stains.

In the case of a pyro developer the iron

apt to combine with the pyro, forming an inky

a bluish-red color to the solution although photographically Particles of finely divided sulphur

is

compound which imparts it is

harmless.

which give the characteristic opal-

escence to sulphur waters will cause fog, owing to the formation of

sodium sulphide by interaction with the carbonate present oping solution.

water

whereupon

it

may

is

usually precipitated

developer.

in the devel-

boiled, the colloidal sulphur usually

is

Vegetable matter

coagulates, b.

If the

be separated by settling or

by the

filtration.

salts present in the

Frequently fungus growths and micro-organisms thrive in

a developer and form a slime or scum on the walls of the tank.

Some

types of these growths act on the sulphite in the developer, changing to

sodium sulphide which fogs the emulsion very badly.

is

removed by developing some waste

The

film in the solution or

it

sulphide

by adding

a small quantity of lead acetate to the developer in the proportion of

60 grains per gallon (i gram per

liter)."*

Tanks which show a tend-

ency to accumulate slime should be scrubbed with hot water at regular intervals

and then treated with a

dilute

sodium hypochlorite solution

Chapter XII, page 265). Suspended mineral, vegetable, or animal matter in general has usually no harmful effect on a developer, provided (see

the mixed developing solution

supernatant liquid drawn

wafm 3

off

is

allowed to stand and only the clear

for use.

Preparing the developer with

water tends to hasten the rate of settling of the suspended matter.

"Chemical Fog" by

Pilot. 66,

J.

I.

Crabtree.

Amcr. Ann. Phot.

33, 20

(1920); B.

J.

97 (1919). 4 " Sulphide Fog by Bacteria in Motion Picture Developers " by M. L. Dundon and J. I. Crabtree. Amcr. Phot. 12, 56 (1925).


EFFECT OF THE WATER SUPPLY ON SOLUTIONS

103

Extracts from decayed vegetable matter or the bark of trees usu-

3.

ally discolor developing solutions but are often precipitated

veloper

prepared with

is

warm water and

ing effect of such extracts

Water

4.

is

dissolves about

the de-

if

The

allowed to stand.

stain-

usually negligible. 2""^

of air at yo^F.

developing agent like hydroquinone

is

(2i°C.) and when a

dissolved without the addition of

sulphite the oxygen present in the water combines with the developing

agent, forming an oxidation product which

form of

apt to stain the gelatin and

is

Air in water occasionally collects on the film in the

fog the emulsion.

bubbles or airbells which prevent development and pro-

little

duce characteristic markings ing at high temperatures

causes blisters

'

(see page 188

'^

(see Fig. 70,

(above 8o°F.)

When

page 144).

(26°C.) dissolved

and Fig. 70).

Mineral waters containing carbon dioxide rarely give provided the water dioxide

way

is

boiled

first in

order to drive

off

present in a developer in excessive amounts,

is

as dissolved

air,

developair often

much

the gas. it

trouble,

If

carbon

acts in the

producing bubbles and airbells on the

film.

drogen sulphide gas will cause bad chemical fog in a developer but

same

Hy-

may

be removed by boiling the water or by precipitating with lead acetate before mixing."It is

*

sometimes thought that water treated with chlorine

suitable for mixing photographic solutions.

Any

may

be un-

chlorine present,

how-

would be destroyed immediately by the sulphite or developing

ever,

agents.

The

chlorine content

is

usually so small that the photographic

properties are not appreciably affected

by

virtue of this destruction of

a trace of the constituent chemicals.

— Calcium and magnesuim

Fixation.

sulphites are soluble in acetic

acid and therefore are not precipitated in fresh acid fixing baths. If the

pH

any scum

value or degree of alkalinity of the bath becomes too high,

of calcium sulphite

prints in the developer

is

which

may have formed on

the films or

not dissolved and remains even after washing.

important, therefore, to keep the fixing bath sufficiently acid by

It is

revival or the use of an acid rinse bath. 5

tree 72,

" Rack Marks and Airbell Markings on Motion Picture Film " by J. and C. E. Ives. Trans. Soc. Mot. Pict. Hinj. No. 24. 95 (1925) B. ;

775 (1925) c

tree. '

;

Crab-

J.

Phot.

73, 4 (1926).

The Handling of Motion Picture Film at High Temperatures " by J. I. CrabTrans. Soc. Mot. Pict. Eng. No. 19, 39 (1924); B. J. Phot. 71, 762 (1924). "Chemical Fog" by J. I. Crabtree. Amcr. Ann. Phot. 33, 20 (1920); B. J.

"

Phot. 66, 97 (1919). 8 " Sulphide Fog by Bacteria in Motion Picture Developers " by M. L. J. I.

I.

Crabtree.

Amcr. Phot.

12, 96 (1925)-

Dundon and


104

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

Other dissolved

salts such as bicarbonates, chlorides, and sulphates are Suspended matter such as dirt, iron rust, and certain types of vegetable and animal matter usually will coagulate and settle out on

harmless.

allowing the fixing bath to stand.

(a)

â&#x20AC;&#x201D;

Drying marks on the film emulsion produced by water on the emulsion side; (b) water on the base side.

Fig. 54

Although most suspended substances have practically no

may

photographic properties of fixing baths, the particles film,

locally retarding fixation,

effect

on the

settle

on the

and producing spots and

stains

(see

Chapter XI, pages 248, 255). Extracts from vegetable matter or dissolved gases do not affect the photographic properties of a fixing bath, but are liable to cause stains and

Washing.

â&#x20AC;&#x201D; Dissolved

blisters,

salts often

and

locally retard fixation.

cause trouble by crystallizing on

the film after drying (Fig. 53, p. loi), and although not always visible as crystals to the eye, they detract from

water containing calcium

salts leave a

its

transparency.

Drops

of

white scum after evaporation.

Water which

is

provided

allowed to remain in droplets on either side of the film dur-

it is

free of dissolved salts also will cause

ing drying^ (Fig. 54). all a.

It is

important therefore to remove thoroughly

excess water from the film before drying.

This can be accomplished

by draining thoroughly before applying a current

9 " Moisture Markings on Motion Picture Film " by J. Matthews. Trans. Soc. Mot. Pict. Eng. No. 17, 29 (1923)

IS (1924).

markings on film

of air, h.

I. ;

by swab-

Crabtree and G. E. J. Phot. 71, 6 and

B.


EFFECT OF THE WATER SUPPLY ON SOLUTIONS bing with wet absorbent cotton, viscose sponge, or chamois, and

means

of a

105

c.

by

pneumatic squeegee.'"

Fig. 55

â&#x20AC;&#x201D; Low pressure steam operated water

still.

(Capacity 15 gallons per hour.)

Suspended mineral, vegetable, and animal matter usually produces a

scum on drying. or

film unless the gelatin surface If the

water used

for

filtered before using for

is

washing

wiped carefully previous to run into a large settling tank

is

is

washing purposes, most of the suspended

matter will be removed (see discussion on

filters,

Chapter

III,

page 31).

Dissolved extracts from bark and decayed vegetable matter produce stains

which are very

difficult to

remove.

In

many

cases, however,

it is

by passing it through a filter containing the wash water is warm, dissolved gases

possible to decolorize such water

activated charcoal.

Also,

sometimes produce

will

sufficiently in the fixing

So far as 10

Mot.

"A

Pict.

is

if

blisters, especially

if

the film

is

not hardened

bath (see page 188).

known, any small

Pneumatic Film Squeegee Etig. No. 30, 270 (1927).

"

traces of impurities left in the gelatin by

J. I.

Crabtree and C. E. Ives.

Trans. Soc.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

106

coating of a film after drying, by virtue of the presence of these im-

wash water, are not

purities in the

liable to seriously

impair the keeping

However,

properties of the films over a period of four or five years.

which are

films

be kept for long periods of time should be washed

to

finally in distilled water.

The Preparation

of

Dye

Solutions.

â&#x20AC;&#x201D; Many

dyes are precipi-

by calcium or magnesium salts and alum. The not always immediate and may occur only after standing

tated out of solution precipitation for a

is

The

few days.

properties of dyes with respect to their rate of pene-

tration into gelatin or the rate at

which they are mordanted are affected

considerably by the presence of metallic ions, or acids, or bases, so that in color

photography or when using

desensitizers, impurities in the water

are apt to produce anomalous results.

Dye

solutions should, therefore,

be prepared with distilled water rather than water containing dissolved salts (see

pages 177 and 326).

Distillation.

â&#x20AC;&#x201D;

Distilled water should be used

water by one process only, namely,

which consists

distillation,

verting natural water into steam which, in turn,

The

liquid form.

whenever possible

for

Chemically pure water can be obtained from natural

mixing solutions.

is

condensed

dissolved salts and impurities do not

in con-

to the

over and

distill

are left behind.

Water

stills

are available in sizes ranging from those which deliver

gallons per hour to those of several

to 2

capacity.

Stills

are most

commonly operated with

pressure steam (Fig. 55).

i

hundred gallons per hour low

either gas or

Small units delivering from

i

to 5 gallons

per hour are also supplied with electric heating units but are usually more

expensive to operate unless a cheap source of current

56A). gas

if

It is

not generally considered

the capacity

is

efficient

both small and large capacity

For very large volumes of for

economy.

The

available (Fig. still

with

greater than 10 gallons per hour unless, of course,

a cheap source of gas can be obtained (Fig. 56B). for heating

is

to operate a

Kerosene

is

also used

stills.

distilled water, multiple effect stills are

used

exact type of installation depends on the needs of the

individual photographer, and manufacturers of water

stills

should be

consulted (see Appendix, page 344). Until recent years block tin has been employed extensively as a construction material for pipe lines and fittings to carry distilled water.

In

and storing distilled water. It lends itself to rapid fabrication, threading, and in long pipe Tin-plated lines does not require supporting to the same extent as tin.

some cases aluminum has been used

for piping


EFFECT OF THE WATER SUPPLY ON SOLUTIONS brass or copper as well as of these install if

aluminum

is

used for storage tank linings but

is

an economical precaution to

It is

automatic spring closing faucets on

aluminum piping

num

aluminum

recommended.

is

employed,

107

all distilled

fiber seats

water

lines and,

should be used in the alumi-

faucets.

— Small

capacity water still heated by a storage battery. Courtesy Barnstead Still and Sterilizer Co., Inc., Boston, Mass. Fig. 56A

electrically

Fig. s6b

water

— Small

still.

capacity gas-heated

Courtesy F.

Stokes

J.

Ma-

chine Co., Philadelphia, Pa.

— Unless

Boiling.

solved salts, and it is

if

the water contains an excessive quantity of dis-

the purchase of distillation equipment

usually sufficient to boil the water and allow

natant portion then fine muslin.

Most

may

be siphoned

off or

colloidal vegetable

it

is

to settle.

prohibitive,

The

super-

the solution filtered through

and animal matter, comprising

slimes and scums, coagulates on boiling and certain lime salts are

changed

to

an insoluble condition and

settle out.

not removed but dissolved gases are driven

by

Dissolved extracts are boiling.

Various types of water filters are available commerbut these do not remove dissolved salts or colloidal matter unless

Filtration. cially,

off

the water has been treated previously with a coagulant.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

108

The

simplest type of water

filter

consists of several layers of fine

cheesecloth or cotton flannel fitted over the end of a hose attached to the

Another type consists of a small metal receptacle

faucet (Fig. 57).

holding a

felt

pad, sand, or other filtering

medium which may be screwed

on the faucet (Fig. 58).

Simple type of water

Fig.

filter.

â&#x20AC;&#x201D;

Fig. 58 Small water filter attached to faucet. Courtesy

Jones

Manufacturing

Co.,

Boston, Mass.

The tubular

filter

shown

It consists of

filter.

guide rod, a

filter

on a flange.

tube,

The

in

Figure 59 represents a useful type of water

an outer metal cylinder, a combination cap and

and a

cylindrical cover

The

filter

minimum

open

consists of an

helical

Water

ward through the wall of this tube. are made by changing the spacing

A this

against a gasket

in

a

alteration in existing piping.

around a circular wire screen.

filter

fits

which permits installation

straight line on the cylindrical cover,

pipe line with a

which

feed and discharge connections are arranged in a

is

winding of filtered

fluffy cotton

by passing

thread

radially in-

Fillers of various degrees of fineness

of the thread or including a layer of

paper inside the winding. reasonable flow of water for most photographic requirements with

type of

filter will

be obtained with approximately 40 pounds water

pressure per square inch.

The

life

depends

in all cases

on the amount of

material to be removed from the water and on the pressure applied.

use of rotary or gear

pumps

rather than piston

pumps

is

The

recommended.


EFFECT OF THE WATER SUPPLY ON SOLUTIONS

Fig. 59

— Small cylindrical

filter

Commercial

Fig. filter.

using cotton

Filters Corp.,

wound

tubular

filters.

Boston, Mass.

Large capacity gravity type water 6o Courtesy Wm. B. Scaife & Sons, Oakmont,

Pa. °f*

Pa.

"^jf

Large capacity pressure type water Courtesy Wm. B. Scaife & Sons, Oakmont,

Fig. 6i filter.

SUPPLY

109

Courtesy


:

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

110

For sand

filtration in plants using

filter

coal, or a

may

25,000 to 500,000 gallons daily, a gravity

be installed (Fig. 60).

Pressure

filters

using sand, char-

composition material are also available of similar capacities to

the gravity type but in general they have not been found to deliver quite as clear water as the gravity type.

much more compact than much floor space Fig. 61 (

a pressure fioors of

filter,

)

Pressure filters

It is often

.

particularly

if

however, are usually

filters,

and, therefore, do not require as

necessary to

the laboratory

pump

the water into

located on the upper

is

a building.

The choice among which 3.

gravity

of a particular type of filter are:

i.

depends on several factors

condition of water supply,

2.

location of laboratory, 4. floor space available, and

For further

tion required.

details, the

capacity needed, 5.

manufacturers of

degree of filters

filtra-

should be

consulted (see Appendix, page 342).

Chemical Treatment. fication * 1.

may be

â&#x20AC;&#x201D; The

following methods of chemical puri-

adopted

Potassium alum

may

be added in the proportion of

grains) to 4 liters (i gallon) of water. carries

down suspended

particles

and

alum introduced

into the water has

2.

A 10%

solution of

and coagulates the

solution.

may 3.

The

no harmful

effect

on the solution

mixing developers and fixing baths.

sodium oxalate may be added

until

no further

slime, although other dissolved salts are left in

Solutions of sodium phosphate and of sodium sulphite also

be used to precipitate calcium and magnesium.

Most

of the

commercial methods of softening water

may

be em-

ployed although such methods do not remove sodium and potassium

One

Dis-

small percentage of

This method removes the calcium and magnesium

precipitate forms. salts

for

gram (15

clears the solution rapidly.

solved salts are not removed by this method.

when subsequently used

i

This coagulates the slime which

salts.

most satisfactory methods consists in passing the water through a tank containing sodium aluminum silicate (zeolite), which possesses the power of exchanging its sodium for the calcium and magof the

nesium present

in the water.

Sodium aluminum

silicate

(zeolite)

+ Calcium sulphate

Sodium sulphate

=

+ Calcium aluminum

silicate

* Water purified by the treatments described is not generally satisfactory for drinking purposes since these treatments are not intended to kill micro-organisms in the water.


EFFECT OF THE WATER SUPPLY ON SOLUTIONS When

the zeolite thus loaded with calcium and

in a strong solution of

common

and magnesium again the chemical

may

for

(about

salt

sodium and

12%)

it

magnesium exchanges

ill

is

washed

its

calcium

thus regenerated, whereupon

is

then be used for further softening.

Calcium aluminum

Sodium aluminum

silicate

silicate

(zeolite)

=

+

+

Sodium chloride

Calcium chloride

â&#x20AC;&#x201D;

62 Portable water softening Courtesy Permutit Co., New York, N. Y. Fig.

unit.

A

compact, portable water softening unit working on the principle

described above

York, N. Y.

It

is

supplied by the Permutit Co., 440 Fourth Ave.,

may

be attached to any household faucet and

of softening 100 gallons of water before

62).

it

is

New

capable

needs to be regenerated (Fig.

Larger water softening units are manufactured by several different

companies, reference to which

may

ing Catalog," published annually

New York, N. Y. A comprehensive

be found in the " Chemical Engineerby the Chemical Catalog Company,

discussion of the relative efficiency of various meth-

ods of water softening has been published by Mills." 11

"

Modern Water Softening

277 (Sept. 1933).

"

by A.

J.

Mills.

/.

Soc.

Dyers and Colorists

41),


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

112

A method exchange

of removal of dissolved mineral solids

removing the ionized dissolved

It consists of

through a bed

from water by organic

has been described by Bird, Kirkpatrick and Melof.^-

filters

in

which the

salts are

by passing the water

solids

converted to acids, and then passing

the acidic water through a second bed in which the acids are removed

from solution

and

to yield a water substantially neutral

free of dissolved

solids.

The Use

of Sea Water.

â&#x20AC;&#x201D; Sea

water contains a relatively large

proportion of soluble salts (about 3.5%) and should not be used for

mixing photographic solutions except other water

is

chlorides, bromides,

last

may

is

and iodides

When

graphic solution. sea water

This

available.

extreme emergencies when no

because the dissolved salts such as

may

retard the action of the photo-

the supply of fresh water available

is

very small,

be used for washing photographic materials provided a

washing or soaking previous

water. ^^

in

Even

to drying

given in distilled or fresh

is

after thorough squeegeeing a considerable quantity of

magnesium

the constituent salts remains and the hygroscopic

chloride

causes " dampness " and tends to accelerate fading of the silver image.

important therefore to wash or soak

It is

treatment, which

is

effective in

Suitability of the

Water Supply.

water supply usually reveals very fulness.

It

may

pure water after the sea water

little

â&#x20AC;&#x201D;A

chemical analysis of the

concerning

its

photographic use-

be of some assistance in indicating the quantity of lime,

oxalate, etc., to be late slimes.

in

removing the hypo.

added

to

The quantity

remove dissolved calcium

of total solids indicates

marks may be anticipated, while the presence

if

of iron,

is

to

The only

prepare a developer with the sample and actually try

compared with the same developer prepared with

coagu-

hydrogen sulphide,

or metallic sulphides should be regarded with suspicion. test

salts or to

trouble from drying

useful it

Also, a large drop of water should be allowed to dry on a film

the

amount

of residual

scum observed.

the trouble to be expected

if

the water

This is

out

distilled water.

and

will indicate the extent of

not removed thoroughly before

drying.

"

of Dissolved Mineral Solids from Water by Organic Exchange by P. G. Bird, W. H. Kirkpatrick and E. Melof. /. Amcr. Water Works Asso. 29, 1526 (Oct. 1937). " Washing Motion Picture Film " by K. C. D. Hickman. Trans. Soc. Mot. Pict. Eng. No. 23> 62 (1925). 12

Filters "

I-''

Removal


EFFECT OF THE WATER SUPPLY ON SOLUTIONS Practical Recommendations. with

warm water

night,

any

If

developing solutions are mixed

(about i2 5°F.) (52'^C.) and allowed to stand over

precipitate or suspended matter will settle out

supernatant liquid

and other

â&#x20AC;&#x201D;

113

may

salts in the

be drawn

water supply

and the clear

The presence

off for use.

sometimes beneficial

is

of calcium

in so far as

they tend to retard the swelling of the gelatin coating of the film during washing.

This

The only

is

advantage

of particular

in

hot weather.

impurities liable to cause serious trouble with developers are

hydrogen sulphide or soluble metallic sulphides.

With such water, about

60 grains of lead acetate per gallon of developer (i gram per should be added before mixing.

phide and any excess lead

is

liter)

This removes the sulphides as lead

sul-

precipitated in the developer and settles

out on standing.

No trouble may be

anticipated with fixing baths prepared with average

samples of impure water provided the bath

is

clarified

by

settling before

use.

In localities where very hard water

mixing photographic solutions, unit.

These are available

in

it is

is

both small, portable

capacity) for amateur or studio use, and

normally require several hundred for

or

100 gallon

sizes (of

in large sizes for plants

more gallons

of water each

which

week

mixing their solutions.

When

washing photographic materials

pated with uncolored water a.

the only source available for

advisable to install a water softening

remove

all

if

little

trouble

may

be antici-

the following precautions are taken:

suspended matter by

filtering, either

by means

of

commer-

by placing two or three layers of cloth over the water outremove thoroughly all excess moisture from the film before drying. Water which is colored brown even after filtering through cloth or

cial filters or let, b.

sand

is

very apt to cause staining of the highlights.

through activated charcoal

is

effective.

Usually

filtering


CHAPTER

VII

TECHNIQUE OF MIXING AND USING PHOTOGRAPHIC SOLUTIONS DEVELOPERS Photographic developers usually contain four solid ingredients as

fol-

lows:

The developing

A.

or reducing agent

(Elon,* hydroquinone, pyro,

para-aminophenol, para-phenylenediamine, B.

The

C.

The

etc.).

preservative (sulphites, bisulphites, and metabisulphites of

sodium and potassium). alkali or activator (carbonates

tassium, and

ammonium;

and hydroxides

of sodium, po-

also borax, borates, amines, etc.).

D. The restrainer (bromides and iodides of sodium and potassium).

The Developing number

or

Reducing Agent.

of different developing agents

photographer from time

â&#x20AC;&#x201D; In

to time, for general use

perior to Elon, hydroquinone,

spite of the large

which have been offered

and pyro.f

to the

none have proved su-

Some photographers

still

use

pyro exclusively, maintaining that a yellow pyro-stained negative

will

give better prints than an Elon-hydroquinone developed negative.

Ex-

tensive tests have shown, however, that

it is

possible to get just as good

prints from negatives developed with Elon-hydroquinone as with pyro.

Of

same contrast as an more contrasty print usually give a

course, a pyro negative which appears to have the

Elon-hydroquinone negative

will

because of the yellow stain image present.

hydroquinone negative

is

If,

however, the Elon-

developed long enough so that

printing contrast as the pyro

it

gives the

same

negative, the quality of the prints for a

given amount of fog on the negative will be identical.

The presence

of the

pyro stain image can readily be revealed by

ducing a pyro-developed negative in Farmer's reducer, which

mixing equal parts of a

5%

solution of hypo.

5%

is

re-

made by

solution of potassium ferricyanide and a

This treatment removes the

silver

image but

leaves the stain image. * The developing agent, mono-methyl para-aminophenol is sold under various Since the experience trade names such as Metol, Elon, Pictol, Photol, Rhodol, etc. of the authors has been largely with Elon, reference will be made to this trade prod-

As supplied to the trade, Elon is a salt of sulphuric acid and methyl para-aminophenol and when dissolved in water it gives an acid reaction. para-aminophenol t Other developing agents which are used less extensively are (amidol), para-oxyphenyl glypara-phenylenediamine, di-aminophenol (p.a.p.), uct throughout this book.

:

cine

The

(glycine),

chlor-hydroquinone, and pyrocatechol (pyrocatechin or catechol). common developing agents are listed in Table 7, page 216

properties of several


MIXING AND USING PHOTOGRAPHIC SOLUTIONS Pyro has one very valuable property which are formed when the developer fog, the

nature of which

is

in so far as its

is

veloper will prevent this fog, which

is

oxidation products,

exposed to the

A

explained later.

115

air,

prevent aerial

trace of pyro in the de-

the reason for using a mixture of

Elon, hydroquinone, and pyro in some formulas.

E

H

E

H

E

Imin.

Imin.

2min.

2min.

4min.

Fig. 63

The

â&#x20AC;&#x201D; Comparative

rates of

development

of

Elon

vs.

H 4min.

hydroquinone.

addition of pyro to an Elon-hydroquinone developer tends to in-

crease the rate of aerial oxidation of the developing agents so that the

quantity of pyro added should be a minimum. In view of the above objections, namely:

poor keeping properties, of

b.

a.

the staining and relatively

the accelerating effect on the aerial oxidation

Elon and hydroquinone, and

c.

the fact that

it

is difficult

to secure

negatives of uniform printing contrast because the quantity of image stain varies with the age of the dev^eloper,

by Elon-hydroquinone is

for the

pyro has been replaced entirely

development of motion picture film and

being discarded rapidly by professional photographers

in

favor of the

more stable Elon-hydroquinone developers. The difference in behavior between Elon and hydroquinone clearly in Figure 63.

The

test

was made with what

are

known

is

shown

as step-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

116

exposed negatives which simply consist of strips of film which have

An

ceived increasing exposures in steps from end to end.

re-

exposed picture

negative likewise consists of a series of patches of irregular shape which

have received increasing exposures so that we

may

consider the lower

density steps in the step negative to correspond to the shadows, and the

higher densities to the highlights of an ordinary negative.

Such step

negatives are to be preferred for testing purposes because they can be

reproduced exactly and can be compared more easily by placing side by side.

Two developers

were prepared, one containing only Elon and the other

only hydroquinone.

Step-exposed strips of film were then developed in

minute, 2 minutes, and 4 minutes, respectively. minute the Elon developer had produced an image of low contrast

each developer for After

I

i

while the hydroquinone had produced only the faintest sign of an image. After

minutes

2

all

the image tones were visible in the case of both de-

velopers but the hydroquinone image was less contrasty than the Elon

After 4 minutes, the two negatives were almost identical.

image.

On

prolonging the development, the hydroquinone image was more contrasty

than the Elon image.

Elon, therefore, brings out the detail quickly but

the hydroquinone builds

The

Preservative.

from oxidizing

sodium sulphite

The

up the

â&#x20AC;&#x201D; In

contrast.

order to prevent the developer solution

in the presence of air, a preservative is or, occasionally,

sodium

added, usually

bisulphite.

sulphite performs a dual function, namely:

i. it

prevents aerial

oxidation of the developing agent, maintaining the solution colorless both

during mixing and storage, and during use.

When

2.

maintains the developer colorless

it

development takes place

sulphite, the developing solution

in the absence of air and becomes colored by the oxidized by-

In the presence of sulphite these oxidation

products of development.

products combine or couple with the sulphite to form colorless sulphonates.

The this

addition of too

for silver halide If

much

chemical in addition to

some

sulphite its

is

and exerts a retarding

silver halide is dissolved

to be avoided, however, because

action as a preservative effect

is

also a solvent

on the rate of development.

from the film as a result of an excess con-

centration of sulphite in the developer, a type of chemical fog called " sulphite fog "

may

be produced (see Chapter XI, page 249).

This

is

caused by the reduction to metallic silver of the silver salts dissolved out

by the sulphite while the emulsion 1

"Chemical Fog" by

J. I.

Crabtree.

is

in the developer.^

Amcr. Ann. Phot.

33, 20 (1919).


MIXING AND USING PHOTOGRAPHIC SOLUTIONS The question

often asked, "

is

sometimes used as preservatives

Why

117

are both sulphite and bisulphite

The

developer?

in a single solution

car-

bonate reacts with the bisulphite to form sodium sulphite and sodium

why

bicarbonate so

answer

is

not use more sulphite in the

place? "

first

The

that developers containing bisulphite tend to give slightly less

fog than those containing only sulphite and

it

has not been possible to

duplicate exactly a developer containing both sulphite and bisulphite

by using a mixture of sulphite and sodium bicarbonate (see further details in Chapter X, page 215). Sodium sulphite is supplied in two forms, namely, the crystalline heptahydrate which has the formula Na.,S0...7HoO, and the desiccated form which contains no water. The water in the crystalline form is united

when it is crystallized and is known as The crystalline form, when pure, requires dry salt when substituting in a formula. The

chemically with the sulphite *'

water of crystallization."

twice the weight of the

desiccated salt as supplied to the photographic market usually contains

96

to

97%

pure sulphite.

Ordinary sodium bisulphite has been shown by analysis chiefly of metabisulphite

which

Sodium bisulphite may be substituted weight

solved in water.

weight for potassium metabisulphite. factory but the former

is

The

and

of three kinds:

The quantity and If

the carbonated

pH

from one-third

alkali if

resulting

is

there

the action of the developer will be retarded. gelatin of the emulsion,

alkalis

present, the developer

is

a deficiency of alkali

Alkalis also soften the

and a strongly alkaline developer in

frilling

or

and the

value of the alkali govern the

an excess of

tend to produce chemical fog, while

over-swelling

costs

available on the American

â&#x20AC;&#x201D;

energy of the developer. will

it

for

equally satis-

Most developing agents will not develop unless in The alkalis most commonly used in development are

the caustic alkalis,

borated alkalis.

is

is

a very pure form.

least, in

Activator.

alkaline solution.

Either chemical

usually preferred since

to one-half the price of the latter

market, at

to consist

converted into bisulphite when dis-

is

blisters,

especially

will

produce

during hot

weather, unless precautions are taken to minimize such tendencies.

The Meaning is

of pH.

â&#x20AC;&#x201D; In comparing the

necessary to understand the meaning of

properties of alkalis,

it

pH values. The acidic proper-

ties of an acid solution are attributable to the presence of free hydrogen ions and, conversely, the properties of an alkaline solution are due

to the presence of free

hydroxyl

ions.

In any aqueous solution, the

product of the concentration of the hydrogen and hydroxyl ions

is

con-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

118

slant so that in a strongly acid solution there

is

an excess of hydrogen

ions in relation to hydroxyl ions and, vice versa, in an alkaline solution

there

is

a relative dearth of hydrogen ions and an excess of hydroxyl

ions.

"

The degree pH," which

of acidity or alkalinity is

usually expressed

is

by

the symbol

equal to the logarithm of the reciprocal of the hydrogen

ion concentration, or

pH

=

Log

^

An

ion concentration.

solution has, therefore, a relatively high

pH

alkaline

value as compared with that

an acid solution.

of

pH

Developer solutions containing caustic soda usually have a

range

of ii.o to 12.0 or higher; those containing carbonate, 9.5 to 10.5; those

containing Kodalk, 9.0 to 10. o; and those containing borax, 8.0 to 9.0,

pH

pure water having a

The

of 7.0.

higher energy developing agents such as Elon which bring up

the image rapidly, require less alkali than the slower developing agents.

Hydroquinone,

for instance,

is

often used with caustic alkalis, while most

other developing agents require only the weaker carbonated alkalis. It

should be remembered, however, that a water solution of Elon

is

acid in character and requires a definite quantity of alkali to neutralize

the acidity before ers

it

will

develop an image.

In weakly alkaline develop-

such as those of the borax type, this neutralizing

much more apparent than with

effect of the

Elon

is

those containing a larger quantity of

carbonate.

The carbonates the carbonate

are salts of a

is split

up

weak

acid, carbonic acid.

carbonate) and caustic alkali.

A

sort of reservoir of alkali

created, only a small quantity of alkali being present at

more

is

generated by dissociation as the alkali

carbonate makes alkali

and

to

keep

it it

In solution,

slightly or dissociated into bicarbonate (or acid

possible to

is

is

thus

any time, but

used up.

The

use of

employ only a small concentration

approximately constant throughout the

life

of

of the

developer.

Sodium carbonate

is

supplied commercially in three varieties, namely,

the decahydrate, which contains ten parts of water to each part of car-

bonate, the monohydrate, which contains one part of water, and the desiccated form, which contains no water.

Very pure grades

of desic-

cated sodium carbonate have been available commercially for years and have found extensive use in

all

many

branches of photographic work.

Within recent years monohydrated sodium carbonate has come into favor with this

some photographers and laboratories because of claims that it is more stable in so

has less tendency to cake on mixing and that


MIXING AND USING PHOTOGRAPHIC SOLUTIONS far as

does not absorb moisture

it

damp weather

in

Experiments have shown that

dry weather.

119

or lose moisture in

desiccated carbonate

if

is

stored with only moderate care in a closed bin, barrel, bottle, or can, the

quantity of water absorbed

is

rarely of sufficient

appreciable photographic effect, while

than that of monohydrated carbonate. crystallization present in the

use

17'^f

The

Na,B^O-.ioH,.0,

to

is

have any

no greater

Also, because of the water of

monohydrated

variety,

more than when the desiccated variety

alkali borax,

magnitude

caking tendency

its

is

is

it

is

necessary to

used.

being used extensively for the

preparation of low contrast developers.

Borax, however, does not ap-

pear to have any specific ability to produce fine grained images but

what

is

known

as a " buffer " alkali, that

is, it

for delivering small quantities of alkali at

is

acts as a large reservoir

any one time

so that during

exhaustion or on the addition of an acid the alkalinity of the solution

does not change appreciably until

Kodalk their

*

â&#x20AC;&#x201D; One

tendency

to

all

the borax has been neutralized.

of the disadvantages of the carbonated alkalis

is

cause blisters within the gelatin layer as a result of the

release of carbon dioxide gas

when

the alkaline developer

is

neutralized

by the acid fixing bath. This trouble is particularly serious in summer months when temperature control of solutions becomes more difficult. Carbonate also tends to precipitate a sludge of aluminum sulphite in a potassium alum acid hardening fixing bath (without boric acid) when the acidity is low by virtue of exhaustion of the bath. The precipitate deposits as an objectionable scum on the surface of films and prints. Both of these difficulties can be avoided by using developers containing borax instead of carbonate but, because of the limited solubility of

borax,

it is

tivity.

By

possible to

compound only developers having

a limited ac-

plotting the concentration of an alkali against the developer

shown in Figure 64, it is seen that in a given formula, 40 grams (ij ounces) of borax are required to give the same activity as 4 grams (60 grains) of desiccated sodium carbonate. activity, as

The shortcomings of both carbonate and borax are avoided by using new alkali known as Kodalk which has properties lying between those With increasing concentrations of the carbonate and borax (Fig. 64.) a

of this alkali, the activity of

idly as

when carbonate

is

an

MQ

developer does not change as rap-

used, so that

it is

possible to control precisely

by varying the concentration of Kodalk. The alkali does not cake when added to water and does not Blister formation is release a gas when added to an acid fixing bath. the activity of a weakly alkaline developer

*

Supplied by Eastman Kodak Co., Rochester, N. Y.


120

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

therefore avoided.

Also, fixing baths containing potassium

alum do not

sludge as readily with developers containing Kodalk as with developers

containing carbonate and trouble from scum formation

mized. in

Formulas containing Kodalk are marked

Appendix A, Chapter XIV, page 279.

0.50

"

is

DK-

"

thereby mini-

and are given


MIXING AND USING PHOTOGRAPHIC SOLUTIONS

121

emulsions, compensation for overexposure by juggling with the bromide

content of the developer

is

no longer necessary.

Moreover, since the

presence of bromide in a developer lowers the effective emulsion speed, it is

if

desirable to maintain the bromide concentration at a

possible, to eliminate

it

Bromide accumulates development so that

if

minimum

and,

entirely.

in the

developer with use as a by-product of

the fresh developer gives a trace of fog, this usu-

ally disappears after the solution has

been used

slightly.

TECHNIQUE OF MIXING Developing Agent and Preservative. like

hydroquinone

velop at

all

brown as a

is

or only very slowly,

quinone with the oxygen present

a developing agent

is

it

will gradually turn

combination of the hydro-

in the air in

This oxidation product

contact with the surface

of the nature of a

dye and

will

dye solution.

stain fabrics or gelatin just like a

On

If

and on standing

result of oxidation or chemical

of the liquid.

dissolved in water, the solution will either not de-

adding a solution of an alkali such as sodium carbonate, the hydro-

quinone solution at once becomes a developer, but at the same time the rate of oxidation

is

increased to such an extent that the solution very

rapidly turns dark brown, and

if

a film

is

developed in this solution,

becomes badly stained and sometimes fogged.

The

it

subject of devel-

oper fog has been treated fully in a series of articles to which reference should be made.-If

we add

a

little

tioned above, the solution

is

'

sodium sulphite

brown

obtained.

to the

color or stain

Therefore,

if

is

brown-colored solution menbleached out and a colorless

the preservative

is

added

first to

the

developer, then on adding the accelerator, the solution should remain perfectly clear because the sulphite preserves or protects the developing agent from oxidation

As a general

An

by the

air.

rule, therefore, the preservative

Elon or a similar developing agent stance 2 3

should be dissolved

first.

exception to this rule should be observed with formulas containing

is

readily soluble in

warm

in concentrated solution.

This sub-

water, about i25°F. (52°C.), and

"Chemical Fog" by J. I. Crabtree. Amcr. Ann. Phot. 33, 20 (1919). (a) " The Fogging Properties of Developers " by M. L. Dundon and J. I. Crabtree, Amcr. Phot. 18, 742 (1924) (b) " Sulphide Fog in Motion Picture Developers " by M. L. Dundon and J. I. Crabtree, Amcr. Phot, ig, 96 (1925) (c) " The Staining Properties of Motion Picture Developers " by J. I. Crabtree and M. L. Dundon, Trans. Sac. Mot. Pict. Eng. No. 25, 108 (1926). ;

;


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

122

does not oxidize rapidly.

If the sulphite is dissolved

white precipitate often appears, especially

if

before the Elon, a

the sulphite solution

con-

is

centrated.

This precipitate forms because Elon base with an acid which renders

weak

neutralized by a

also in a solution of

sodium

When

the acid portion

is

sulphite, the insoluble base

is

soluble in an excess of water

is

sodium carbonate with which the base forms a

When

salt.

a combination of an insoluble

sodium

This Elon precipitate

precipitated.

ble

alkali such as

is

soluble.

it

once the Elon

is

dissolved, however,

fairly high concentration of sulphite to bring

though only a low concentration of sulphite

Elon from dissolving.

is

and

solu-

takes a

it

out of solution again,

it

required to prevent the

a precipitate forms on dissolving the Elon and

If

sulphite, this will usually redissolve

on adding the carbonate or alkali

and no harm has been done.

Some

direction sheets

be dissolved

first in

little

that a portion of the sulphite should

and then the remainder

solve the Elon,

add a

recommend

order to prevent the oxidation of the Elon, then dis-

of the solid sulphite to the

This procedure

of the sulphite.

quite satisfactory, though

is

Many

workers

Elon when dissolving the the Elon

if

is

latter.

dissolved

alone in water at a temperature not above i25°F. (52°C.), and the sulphite dissolved immediately afterwards, will

little

or

no oxidation products

be formed, which otherwise might produce chemical stain.*

Activator. 1.

â&#x20AC;&#x201D; The

solution.

There

the alkali

is

2.

alkali

may

be added

in

one of three ways:

Dissolve the alkali separately and add to the cooled Elon-sulphite

Add

is

danger, however, of the Elon precipitating out before

added.

the solid alkali to the Elon-sulphite solution, stirring thor-

oughly until dissolved. 3.

cool,

After dissolving the Elon, dissolve the sulphite and alkali together,

and add

to the

Elon solution.

to the developing agent,

substance

is

even

formed which

in the

If a

hot alkali solution

is

added

presence of the preservative, some

may produce

chemical fog with certain devel-

oper samples.

In the case of some samples of para-aminophenol which are discolored

by by

the presence of oxidation products, these

may

boiling after adding to the sulphite solution.

tion products are reduced again

by the

be partially removed

In this way, the oxida-

sulphite to colorless products

* The quality of chemicals supplied for photographic work has improved greatly since 1920 and they have less propensity to produce fog, colored solutions, etc., if the

above precautions are not observed.


MIXING AND USING PHOTOGRAPHIC SOLUTIONS

123

though the sokition should be cooled again before adding the alkali. If pure chemicals are used, such a procedure is, of course, unnecessary. In the case of desiccated chemicals like sodium carbonate and sodium sulphite,

add the chemical

The

ing will result.

Restrainer.

to the

It is

water and not vice versa, otherwise cak-

Kodalk,

alkali,

is

not subject to caking.

immaterial at what stage the bromide

is

added

during the mixing.

GENERAL HINTS ON MIXING DEVELOPERS 1.

Water Temperature.

except 2.

ber. 3.

when

— Use

a higher temperature

is

water at i25°F. (S2°C.) or

less

recommended.

specifically

— Use good enamelled ware, ware, or hard rubwhich cause Avoid copper, or galvanized mixCheck the Formulas. — Arrange the chemicals needed Containers.

glass

fog.

iron

tin,

for

ing at one end of a shelf or bench.

As each one

is

weighed out, place the

Use only

stock can or bottle on the opposite side of the shelf or bench.

chemicals of reliable manufacture. 4.

Water

First.

Caking

chemicals.

— Pour water

results

into the container,

from adding water

to

and then add the

dry chemicals.

Boiling

water should never be used unless specifically recommended. 5.

Avoid Premature Oxidation.

— Add

water before adding the developing agents.

Elon because of 6.

its

This

slow rate of oxidation.

Complete Solution of Each Chemical.

cal completely before

adding the next and

a

little is

sulphite to the

not necessary with

— Dissolve each chemi-

in the order given.

PRACTICAL RULES FOR MIXING DEVELOPERS The

following practical procedures are

recommended

for

mixing de-

velopers, unless definite instructions otherwise are given with the formula.

A. For Mixing Small Volumes of Developer (Less than 5 Gallons).

i.

Weigh out

all

of the chemicals, placing each one on a

separate piece of paper on which is

its

name and weight

are written.

It

then possible to check the chemicals before starting to dissolve them,

thus greatly reducing the possibility of error.

Be

sure that the scales

are sufficiently accurate, particularly for the developing agents, potas-

sium bromide, and any other ingredients which are used discussion on scales, page 15).

in

small quan-

tities (see 2.

Into a container large enough to take the

tion place a

volume

of

warm water

full final

volume

of solu-

(not over i25°F.) (52°C.), equal to

one-half to three-quarters of the total volume to be used.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

124

Elon

3. If there is it is

4.

to the

it

water and

stir until

completely dissolved.

Add

the sulphite or other preservative (bisulphite, potassium meta-

and

bisulphite, etc.)

Add and make 5.

6.

add

in the formula,

stir until fully dissolved.

the remaining developing agents (hydroquinone, pyro, etc.) sure that they are completely dissolved.

If the

formula contains an acid material,

in addition to a carbonate,

the acid substance should be dissolved and mixed in with thorough stirring. 7.

Dissolve the alkali (carbonate, Kodalk, borax, etc.) and mix.

the formula contains caustic soda,

it

Then pour

small volume of cold water.

If

should be dissolved separately in a the caustic solution in slowly

while stirring the remainder of the developer. 8.

Dissolve the potassium bromide and any other remaining ingre-

dients. 9.

After

all

the chemicals have been dissolved in turn, add sufficient

cold water to bring the solution

oughly

mix

in order to

up

to the correct

volume, and

stir thor-

the water with the heavier solutions already

present. 10.

Filtering

used, but

if

is

there

unnecessary is

if

clear water

and clean chemicals are

evidence of a sediment or suspension, the solution

Complete directions on

should be filtered before use or storage.

filter-

ing are given in Chapter III, page 31. 11. If the solution in

is

not to be used immediately,

a clean bottle of the proper

An example

of this

method

size,

of mixing

Developer

is

A grains

45

Sodium

Sulphite, desiccated

Hydroquinone

1

'2

2J

ounces grains

135

Sodium Carbonate, desiccated Potassium Bromide Water to make

should be placed

as follows:

Avoirdupois

Elon

it

stoppered, and labeled plainly.

2

ounces

15

grains

32

ounces

Metric 3.1

45.0 9.5 75.0

grams grams grams grams grams

1.1 1.0 liter

Dissolve the Elon in 16 ounces (500 cc.) of water (about I2S째F.) (52째C.), then add the sulphite, and when completely dissolved, add the hydroquinone. Finally add the carbonate and bromide and cold water to make 32 ounces (i liter).

An

above consists in weighing out and Pour the mixture slowly into 90^0 of the water with rapid stirring and then dilute to volume. only satisfactory for small volumes of solution. The

alternative

method

to the

mixing the dry chemicals. total

volume

This method

of is

dry chemicals must also be mixed uniformly and added immediately to the water. If the dry mixture is allowed to stand around for an hour or


MIXING AND USING PHOTOGRAPHIC SOLUTIONS so,

may

it

absorb moisture from the

and produce B. For

125

dissolve with great difficulty,

air,

a colored solution.

Mixing Moderately Large Volumes of Developer

to 500 Gallons).

— The

following procedure

is

safe

and

(5

probably

is

more economical of time. 1. Weigh out the chemicals and check all weights carefully. It facilitates weighing if two pairs of scales are provided, a large one and a small one. 2.

In a tank large enough to take the

volume

final

of solution, place

a volume of water equal to about one-tenth the final volume. 3.

In a separate container (enamelled pail or rubber bucket

Chapter IV, page 68) dissolve each of the chemicals

volume of warm water (not over

see

in turn in a small

(52°C.) and add to the

i2 5°F.)

A

tank, stirring after each addition to insure thorough mixing.

small

quantity of the sulphite solution should be saved and added to the water in

With some developing

which the developing agents are dissolved.

agents, hydroquinone for example, the total quantity should be divided into

two or more parts and each part dissolved separately.

Also,

it

is

somewhat by adding a por-

usually desirable to cool the tank solution

tion of cold water before adding the solution of the alkali. 4.

Add

cold water to bring the solution to the correct volume and stir

thoroughly to insure complete mixing of

As an alternative

all

to the above, the filter

ingredients.

bag method may be more

convenient (see Figs. 14A and 14B, page 33).

bag

is

In this method, a cloth

suspended over the tank and each chemical placed

solved in turn by allowing a stream of

Do

bag into the tank.

warm

in

it

and

dis-

water to flow through the

not add the water so rapidly that the final vol-

ume is reached before all the chemicals are dissolved. An example of this second method of mixing is as follows: Developer B Metric

Avoirdupois

Sodium

Sulphite, desiccated

Hydroquinone

Sodium Carbonate, desiccated Potassium Bromide Water to make

4

pounds

13

ounces

4

pounds

3 ounces 10 gallons

1800.0 390.0 1800.0 90.0 40.0

(irams

grams $)rams f^rams liters

Dissolve the sulphite in about i gallon (4 liters) of warm water (not over i25°F.) (52°C.). Pour about three quarts of this solution in the tank and add i gallon of

warm water

to the

solution to the tank.

Then when completely

remaining quart of sulphite solution.

(luinone in this dilute sulphite solution

Now,

and,

dissolve the hydrodissolved,

dissolve the carbonate and the bromide in

i

add

gallon of

this

warm

Add cold water immediately to (40 liters). Stir the entire volume of solution with a paddle or a mechanical stirrer until thorough mixing is assured. water (not over I25''F.) ($2°C.) and add to the tank.

make up

to 10 gallons


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

126

C.

For Mixing Very Large Volumes of Developer (500 or

More

Gallons).

— When mixing very

as 500 or 1000 gallons (2000 or

4000

volumes

large liters)

of solution such

or more, the heating or

an important

cooling effect of chemicals going into solution becomes

temperature of the solution when

It is desirable also that the

factor.

mixed should approximate that required

finally

amount

A minimum

for use.

For mixing most

of handling of chemicals should be necessary.

developers (except very concentrated solutions), the use of

water

may

warm

or hot

be dispensed with, providing the volume of water used

sufficiently large

when

is

use of automatic

than hand stirring (see page 27).

stirrers is preferable rather

The temperature

The

dissolving the chemicals.

of the water in

range from season to season.

most cities varies over a fairly wide good practice, therefore, to install

It is

a tempering or mixing device which delivers water at a temperature

somewhat

suitable for use, say, 70°F. (2i°C.) or

the heat of hydration 88).

when

This device could be used most effectively

to heat the

it is

compensate

in the winter

water up to the temperature specified.

tant to cool the tap water in the unless

less to

for

dissolving desiccated sodas (Fig. 42 A, page

summer months

for

months

not so impor-

It is

mixing purposes

necessary to do so in connection with an installation for cool-

ing the solutions during use (see page 89)

Care must be taken not

to use too

much water

or the total

volume of

Some

the developer as finally mixed will exceed the prescribed volume.

chemicals increase the volume more than others; for example, sulphite increases the

volume about

3%

(for a

concentration of carbonate increases

Example.

— When

it

20%

solution), whereas the

same

only i^/r.

mixing 1000 gallons of an Elon-hydroquinone

developer, the tank should

first

be

filled

about half

water.

full of

About

one-quarter of the total quantity of sulphite should then be added to the tank,

and

Then add the hydroquinone.

After this solution has been stirred for

10 or 15 minutes, add the sodium carbonate.

next be run in to solution.

Elon should be added.

after stirring about 5 minutes, the

fill

Then add

the tank to about

80%

Sufficient

the balance of the sulphite,

other ingredient such as bisulphite and citric acid.

volume.

The

stirrer

water should

volume of the the bromide, and any

of the final

Dilute to the final

should be run for about one-half hour after the

chemicals have been added to insure a uniform solution throughout the

mixing tank.

The

valve

may

then be opened and the solution run into

the feed or storage tank, either directly a

pump.

A

filter

may

be installed

by gravity feed

or

by means

of

between the mixing tank and the


MIXIXG AND USING PHOTOGRAPHIC SOLUTIONS

127

feed tank or between the feed tank

and the developing machine (see Chapter IX, page 209). A convenient scheme for mixing and supplying solutions to automatic developing machines is shown in Figure 19, page 39. The solution should be mixed

tanks located preferably above the storage or feed

in

tanks which permits a gravity flow of the solution as shown

pumped

may

diagram A.

Any

tank as in diagram B.

to the feed

type of stirring device

be utilized in the mixing tank but the portable motor-driven pro-

peller stirrer illustrated will be

"

in

space necessitates mixing in a basement, the solution must be

If floor

Theory

of Stirring,"

found very

efficient (see discussion

on

page 28).

Mixing Concentrated Developers. — The extent to which a demay be concentrated is determined by the solubility of the least

veloper

soluble constituent, because a stock solution should usually withstand

cooling to 40°F. (4°C.) without

Table of

any

of the ingredients crystallizing out

page 338). Usually, the hydroquinone and Elon come out of solution on cooling, but this may be prevented by add(see

ing

wood

alcohol If

Solubilities,

alcohol or methanol in a concentration

may

be used

wood

if

on adding denatured alcohol

denatured alcohol

is

up

to

10%.

Denatured

alcohol has been added as the denaturant. to the developer, a precipitate forms, the

unfit for use.

The

addition of the alcohol does not

prevent the other ingredients such as sodium sulphite from crystallizing

and therefore

out; in fact, the alcohol diminishes their solubility creases the tendency to

A

come out

para-aminophenol-carbonate developer

by adding a

centrated form, though the para-aminophenol

is

in-

of solution. is difficult

to

prepare

in

con-

caustic soda the solubility of

little

increased and a stronger solution can thus be

prepared.

When

preparing concentrated developers,

it

is

important to observe

carefully the rules of mixing, taking care to keep the temperature of the

solution as low as possible but yet high if

a colorless developer

The

is

following formula

oper and

is

enough

to dissolve the chemicals

to be obtained. is

a typical example of a concentrated devel-

prepared by dissolving the ingredients

in the

order given:

Concentrated Elon-Hydroquinone Developer Avoirdupois

Water (about

Wood

125° F.) (52° C.)

Elon

Sodium

ounces

16

4'^ ounces

.\lcohol

grains

7.?

Sulphite, desiccated

2':^

^

Hydroquinone

Sodium Carbonate, desiccated Potassium Bromide Cold water to

make

3'

^7 32

2

ounces ounce ounces

Metric 500.0 cc H5.0 cc .5.0

75.0 22.5 105.0

grams grams grams grams grams

grains

2.5

ounces

1000.0 cc


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

128

When

mixing large volumes of an Elon-hydroquinone developer con-

taining a high concentration of sulphite, there

is

a tendency for precipi-

tation of the insoluble base of Elon as explained on page 122.

tendency

may

example,

in

This

be minimized by using a definite mixing technique.

For

mixing large volumes of the low contrast developer (D-yb)

the procedure should be as follows:

Elon-Hydroquinone-Borax Developer

[D-76]

Metric

Avoirdupois

Elon

2

Sodium

Sulphite, desiccated

100

Hydroquinone

5

Borax, granular

Water

to

Directions. in

2

make

1

— Dissolve about

a small volume of

pounds pounds pounds pounds

5.0 2.0

grams grams grams grams

1 .0

liter

2.0

100.0

20 gallons

pounds (900 grams) of the sulphite water (about i25°F.) (52°C.) in an enameled pail 2

or other suitable mixing vessel and add the Elon slowly with stirring.

When

completely dissolved, pour the solution through a cloth

pended over the large tank.

(This

may

filter sus-

be the tank actually used for

development or a storage tank from which the solution

is

pumped

to

the developing tank.)

Divide the hydroquinone into three or four parts. 4 pounds (1800 grams) of sulphite in

and add one of the fractions

When

of the

Dissolve about

hot water (about i6o°F.) (7i°C.)

hydroquinone slowly with

stirring.

Repeat the procedure

dissolved, filter the solution into the tank.

with each of the other fractions of hydroquinone.

The remainder of the sulphite should then be added to the tank by dissolving as much as possible in separate pails of water (about i2 5°F.) (52°C.), and pouring each pailful of solution into the tank. The volume of the solution should now be about 80% of the total volume (90 gallons or 360 liters) after

all

the sulphite has been dissolved and added

to the tank.

Next

dissolve the borax in a pail of water.

the tank and add cold water to

(480

make

Filter the solution into

the total

volume 120 gallons

liters).

It is

important to

stir

the solution in the large tank thoroughly after

adding each pailful of chemicals {especially the developing agents) and again after the solution has been diluted to volume. This prevents the heavier chemical solutions from remaining at the bottom.

Multiple-solution Developers.

— A two-solution developer

is

sim-

ply a one-solution developer split into two parts, one containing the

developing agent and the preservative, the other containing the alkali

and bromide,

so that the developer will oxidize less readily

and therefore


MIXING AND USING PHOTOGRAPHIC SOLUTIONS keep

well.

The reason

two solutions

is

it is

that pyro

129

customary to keep a developer like pyro in becomes oxidized much more readily than

Elon or para-aminophenol with a given amount of preservative, while keeps well

it

in acid solution.

Developers containing caustic soda as the alkali are usually prepared as two stock solutions.

Sometimes a developer

solution formula in order that the alkali

portions to the solution

when

it is

may

is

prepared as a two-

be added in varying pro-

diluted for use.

Pyro developers are occasionally made up in three stock solutions the pyro, bisulphite, and bromide in one solution, the sulphite in another, ;

and the carbonate

mum

in the third solution.

This scheme insures the maxi-

protection of the pyro against oxidation and permits the user to

vary the proportions of the three solutions

if

desired

when mixing them

for use.

When

developers are quite concentrated, the formulas are sometimes

more parts and arranged to facilitate easy mixing. which have a tendency to oxidize very rapidly (such as Formula D-87, page 300), it is customary to dissolve all the chemicals first except the pyro and the bisulphite. Then, when ready to develop, add the bisulphite-pyro solution, dilute to volume, and published

in three or

\\'hen mixing pyro developers

use the developer immediately.

— In

Two-Bath Developers.

the two-bath process (development

in successive baths), the first solution usually consists of

an Elon-hydro-

quinone developer containing sodium sulphate or sugar

to retard devel-

opment, while the second bath contains the activator, a portion of the sulphite, and the restrainer. One type of developer which was compounded for rapid processing contains formaldehyde and sodium sulphite, which react to form sodium hydroxide.^ This second bath, therefore,

hardens the emulsion and likewise accelerates the developing action

of the developer solution absorbed

by the

film

from the

first

bath.

Compo-

Effect of Varying the Proportion of the Developer nents.

— The question

is

frequently asked, "

What

is

ing the quantity of the ingredients in a developer? "

the effect of vary-

At the

should be stated that normally there should be no reason the ingredients of a manufacturer's formula regular development of a product.

•*

"

when

Much time

Rapid Processing Methods " by H. Parker,

is

Jr.,

it is

to

outset,

for

it

varying

be used for the

spent in the preparation

and

J.

I.

Crabtree.

Anter.

also " Some Properties of Two-Bath Developers Phot. 30, 67 ct scq. (Feb. 1936) for Motion Picture Film " by J. I. Crabtree, H. Parker, Jr., and H. D. Russell. /. Soc. ;

Mot. Pict. Eiig. 21, 2\ (July 1933).


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

130

and the quantities

of such formulas

group of ingredients which,

of chemicals represent a balanced

for best results,

should be used as recom-

mended. Occasions

however, when a photographer

arise,

perimental work, or

may have

may

contemplate ex-

a peculiar set of conditions in his

own

studio or laboratory necessitating the adaptation of a special developer.

For such contingencies,

may

of chemicals

which

approximate

effect of

To answer

desirable to

is

it

know

the limiting quantities

be used when compounding a formula and the

each on the performance of the developer.

these questions adequately would require a separate trea-

but briefly, increasing the quantity of developing agents increases

tise,

the activity of the developer up to a certain point beyond which a further increase has

Elon

fact that

little

no

or

effect.

In practice,

we

are limited

by the The

not very soluble in a solution of sodium sulphite.

is

solubility can be increased

by adding alcohol

development.

in turn, restrains

The

to the developer but this,

solubility of developing agents in

a developer depends on the salt concentration (sulphite, carbonate, etc.)

and the degree of alkalinity (pH) of the solution. In general, the lower the salt concentration and the higher the pH value, the greater the solubility of the

developing agents.

The maximum per

liter

per

liter

tion of

useful quantity of Elon

(32 fluid (32 fluid

is

about lo grams (150 grains)

ounces) but for average purposes

ounces)

hydroquinone

is

is

The

adequate.

about 50 grams

(32 fluid ounces) although a strength of

(i

5

5

grams (75 grains)

limiting useful concentra-

ounce 290 grains) per

liter

to 10 grams (73 to 146 grains)

more generally used. With developer formulas of the borax type which usually contain a large quantity of sodium sulphite (approximately 10%) the limiting solubility of Elon is approximately 7.5 grams per liter whfle the maximum permissible concentration of Elon and hydroquinone in the ratio of 2:5 is 3 and 7.5 grams per liter, respectively.

is

Glycin

is

of sulphite

almost insoluble in water but

and

alkalis.

An

is

quite soluble in the presence

average concentration in a developer con-

taining about 20 grams per liter (290 grains per quart) of sulphite 5 to

10 grams (73 to 146 grains).

about 50 grams of glycin per

A per

liter

A

limiting useful concentration

(i oz.

290 grains per 32

is is

fluid oz.).

concentration of 50 grams (i ounce 290 grains) of sodium sulphite liter

(32 fluid ounces)

keeping properties.

ment and

to exert

is

A higher

usually sufficient to provide satisfactory

concentration tends to slow

down

develop-

an appreciable solvent action on the emulsion grains.


MIXING AND USING PHOTOGRAPHIC SOLUTIONS The

limiting useful concentration of sulphite

ounces) per

A of

liter

131

about 150 grams (3^

is

(32 fluid ounces).

strength of about 25 grams (375 grains) per

(32 fluid ounces)

liter

sodium carbonate (desiccated) represents an average concentration of

An

this alkali in developers.

up the development

increase in the quantity of carbonate speeds

to a strength of

about 50 grams

(

i

ounce 290 grains)

Beyond this concennot appreciably speeded up but with over 150

of the desiccated salt per liter (32 fluid ounces).

development

tration,

grams lize

is

(5 ounces) per

liter

(32 fluid ounces) the salt tends to crystal-

out at room temperature.

and carbonate

down

also slows

An

excessive concentration of sulphite

the rate of diffusion of the developer into

the gelatin film and tends to retard development. trated developer, therefore, often speeds

A

up the

useful concentration of the alkali, Kodalk,

grains) per liter (32 ounces).

The

ounces)

is

reached.

grams

is

about 10 grams (145

activity of a given developer in-

creases almost proportionately with the limiting concentration of 40

Dilution of a concenrate of development.

(i

Kodalk concentration ounce 145 grains) per

liter

(32

This property of the almost proportionate change

in developer activity with increased alkali concentration

useful properties of Kodalk, because

it

is

one of the

permits adjustment of the activ-

moderately alkaline developer.

ity of a

Trisodium phosphate concentration

is

activity tends to

The

.

is

used occasionally

in developers.

An

average

about 15 grams (4 ounce) per liter (32 ounces). The increase with increased alkali content to a limiting con-

centration of about

ounces)

until the

100 grams (3 ounces 145 grains) per liter (32 is its propensity to cause

objection to the use of this alkali

the formation of an insoluble precipitate of

aluminum phosphate

in the

fixing bath.

An

average concentration of sodium or potassium hydroxide

10 to 20 grams per

These

liter

is

about

(145 to 290 grains per quart) of developer.

alkalis are extremely soluble

and

their use

is

therefore limited

by

the quantity that can be added without producing excessive fog or

swelling of the emulsion.

borax per

liter

At 6o째F. (i5째C.) a maximum

can be dissolved.

As the proportion

grams

of 20

of borax

is

of

increased

from a zero value, the rate of development increases rapidly up to a liter beyond which the development rate

concentration of 10 grams per increase

A

is

relatively slow.

useful concentration of potassium bromide for the average negative

developer

although

is i

its

to 1.5

grams (15

to 25 grains) per liter (32 fluid

use should be avoided whenever possible.

ounces)


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

132

â&#x20AC;&#x201D;

Testing the Mixed Developer. Every developer solution should be tested before use. As mentioned previously (page 13) the use of a hydrometer a developer.

is

meaningless for determining the satisfactory condition of

The only

or paper) therein for a

reliable test

known time

is

develop an exposed film (plate

to

at a definite

temperature and to com-

pare the resulting image with a standard image which has been exposed

and developed under known conditions

in a similar

Testing a Tank Developer During Use. isfactory

methods

manner.

â&#x20AC;&#x201D; One

of the most sat-

from

of testing a tank developer consists in printing

a standard master positive using controlled exposure and comparing the quality of the developed negative obtained with that of a standard nega-

The developed

good quality.

tive of

negative should match the standard

both with regard to highlight density and shadow

detail.

highlight density (which largely determines the contrast

low)

is

ment

or

If

the

the fog

is

weak, this indicates the need either of a longer time of develop-

more replenisher or both.

standard but there

If the contrast

is

equal to that of the

a considerable loss of shadow detail, this indicates

is

that the developer has accumulated an excess and a fresh developer should be prepared.

A

if

of restraining products

rapid test for determining the degree of exhaustion of developers has

been suggested by Dundon, Brown and taining a sensitometric exposure

is

ing the time accurately to the second.

ment (30 seconds

to

minutes),

2

Capstaff.'^

dipped quickly

it is

A

strip of film con-

in the developer, not-

After a short time of develop-

removed and plunged

hardening stop bath containing potassium iodide.

into an acid

This bath neutralizes

the alkali in the developer and stops development, and the iodide converts the undeveloped silver to

examine the

strip at

once

bromide

to iodide

in the light

which makes

(without fixation).

it

possible

Compari-

son with a standard indicates the degree of development which has taken place in the used developer.

For best results the

test

must be standard-

ized for the developer used.

THE LIFE OF DEVELOPERS A. Without Use. water boiled to free

it

â&#x20AC;&#x201D;

If

a freshly mixed developer (prepared with

from dissolved

air) is stored in a

completely

filled

and stoppered or wax-corked bottle, it will keep almost indefinitely even in the light. Under ordinary conditions of storage, the bottle or vessel contains more or less

cover 5

/.

is

air.

Also,

when an ordinary cork

employed, the surface of the developer

Soc. Mot. Pict. Bug. 14, 389 (April 1930).

is

or non-airtight

continually in contact


MIXING AND USING PHOTOGRAPHIC SOLUTIONS with

air,

133

the oxygen constituent of which oxidizes the developing agent

and sodium sulphite present. This results in a lowering of the developing power in direct proportion to the amount of oxidation of the developing agent, which is accelerated as the preservative or sodium sulphite becomes oxidized

The

also.

oxidation products of developing agents are usually colored so

that the developer on keeping frequently turns dark brown.

presence of sodium

may

quinone

consist of hydroquinone

colorless

is,

The

mono- and di-sulphonates which

an old Elon-hydroquinone developer is therefore, no indication that the original developing power

are colorless."

is

In the

sulphite, however, the oxidation products of hydro-

unimpaired.

An

fact that

oxidized Elon or Elon-hydroquinone developer also

frequently fluoresces strongly.

Developers of low or moderate alkalinity containing Elon and hydroquinone may actually show an increased rate of development on aging which, in the case of a developer containing borax as the alkali, plained by Carlton and Crabtree alkalinity. *

This

effect

may

by the formation

gators

"'

of the

hydroquinone

in the

"

is

ex-

as resulting from an increase in the

be explained according to several investiof caustic soda during the aerial oxidation

presence of sulphite, which reaction also re-

mono- and di-sulphonates of hydroquinone. studied this effect and reported similar results. The

sults in the formation of

Tausch

"

has also

effect of this increased alkalinity rapidly disappears,

as a sufficient quantity of the hydroquinone

is

however, as soon

used up to reduce

effec-

tively its initial concentration.

A will

solution of a developing agent to be stored for a considerable time

keep best

in the presence of

an acid sulphite such as sodium

phite rather than sodium sulphite which

ways

slightly alkaline.

is

bisul-

It is al-

preferable, therefore, to prepare a developer as two solutions: one

containing the developing agent and sodium bisulphite, and the other the carbonate and bromide, and to mix these solutions as required for

Stock solutions containing sodium sulphite alone or in combina-

use.

tion with a developing agent should be prepared so that the concentra-

tion of the sulphite erties/"

Sodium

is

around

io%

to

15%

for

Pinnow.

"

Trans. Soc. Mot. Pict. Eng. No. J*. 406 (1929)Camera (Luzern) 9, 128 (Nov. 1930).

Zeit. wiss, phot, ii,

more

keeping prop-

dilute solutions

289 (1912-13).

c

8

maximum

bisulphite keeps satisfactorily in

Phot. lud. 29, 934 and 1320 (1931). A. & L. Lumiere and A. Seyewetz. Bull. soc. franc, phot. (2) 5. 226 (1904) also L. Lumiere and A. Seyewetz. Bull. soc. chim. (3) 33, 444 (1905)9

10


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

134

and

is

a better preservative than sulphite in the absence of carbonate.

It is usual therefore to

keep readily oxidizable developing agents such

by mixing with sodium bisulphite. On adding sodium carbonate to sodium bisulphite, sodium sulphite and sodium bicarbonate are formed, so that in compounding a two-solution formula as pyro, amidol, etc.,

from a one-solution formula

it is

necessary to take care of this neutraliza-

by using an extra quantity. A more complete dissubject will be given later in Chapter X on " Substitution

tion of the carbonate

cussion of this of Chemicals."

Fig. 65

â&#x20AC;&#x201D; Restraining

effect of

developer reaction products on wet and dry iilm.

Single solution developers containing sodium hydroxide or potassium

hydroxide do not keep well unless the bottle

B.

With

pends on

its

Use.

â&#x20AC;&#x201D; The

life

is

stoppered tightly.

or period of usefulness of a developer de-

particular composition, the surface area exposed to the air,

the temperature, the degree of agitation, and whether the solution

is

used

During development, several reactions the developing agent (s) and sulphite are being

continuously or intermittently. are taking place:

i.

oxidized

by

result of

performing useful work

the air;

2.

each developing agent

is

in reducing the

being destroyed as a

exposed

silver halide

and 3. oxidation products of the developer and the by-products, sodium bromide and sodium iodide, are accumulating. The bromide and iodide and developer oxidation products restrain development while the oxidation products prevent aerial fog. The restraining action of the bromide and iodide is analogous to cutting down the exposure, so that with an old developer it is not possible even on prolonged development to get the ultimate result out of an underexposure. emulsion to metallic

silver;


MIXING AND USING PHOTOGRAPHIC SOLUTIONS The

essential changes going

on

in

135

a developer during use therefore

consist of a depletion of the developing agent (s)

and the accumulation

of restraining products, chiefly developer oxidation products together

with sodium bromide and sodium iodide.

Exhausted

Fresh Fig. 66a

â&#x20AC;&#x201D; Effect

negative quality.

The shown

â&#x20AC;&#x201D; not

replenished

of developer exhaustion without replenishment on

Negatives developed for equal times.

restraining effect of the developer reaction products

Figure 65.

in

of holes

is

clearly

This picture was obtained as follows: a number

were punched in a sheet of black paper which was used as a

negative to expose two sheets of film.

The

were then slightly

films

fogged and afterwards both were developed in a tank while held stationary.

One

of the films

was soaked

in

In

water previous to development.

the case of the dry film the reaction products of development which are

downward and

heavier than the surrounding developer gravitated

re-

strained the development of the fogged area immediately below the black circles,

thus producing white streaks.

reaction products diluted with water

In the case of the wetted film, the

had a lower

specific gravity

than

that of the developer and therefore traveled upward, producing streaks.

A

similar effect occurs during the development of

image at the junction of a shadow and a highlight and in the print as a

white line around a dark object.

"

The

Mackie

line."

effect is

posed negatives developed for full

development.

It is

any photographic is

This

often apparent is

known

as a

more noticeable in the case of fully exa short time and tends to disappear with

Agitation will largely prevent

it.

very important to get a clear conception of the effect of the de-

veloper reaction products on the nature of the developed image as the

developer becomes exhausted.

It is well

known

that potassium bromide


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

136

development and has an

restrains

An

exposure. ucts

maximum

therefore incapable of getting the

is

produced by

effect similar to that

less

old developer contaminated with developer reaction prod-

out of an underex-

posure so that films developed in an old developer appear relatively

The

underexposed.

effect of

exhaustion

is

shown

Figure 66A, which

in

developed for a standard time

illustrates test negatives

in

a fresh devel-

oper and also after exhausting with loo rolls per gallon (i aver,

one 8 by lo-inch film) without replenishment.

roll

=

Both negatives were

given the same time of development.

some extent by shadow detail The loss of shadow

It is possible to offset these effects of exhaustion to

prolonged development but there

even with longer development detail

is

more

serious also

in a

is

always some

loss of

used developer.

when developing

to

low contrast than at higher

contrast.

The

addition of a suitable replenisher solution to

many

developers,

however, will compensate for this loss of shadow detail to a considerable Detailed information has been published on replenishment of

extent.

developers for motion picture work and for photofinishing.^^

Replenishers usually contain an excess of developing agents and alkali over the original formula, and the same sulphite but no bromide.

It is

the additional developing agents and alkali in the replenisher which offset the restraining effects of the

bromide and the developer reaction

products.

The extent of the maintenance of shadow detail by replenishing in way is shown in Figure 66 B, which compares prints made from a

this

negative developed in a fresh developer and from a negative developed for the

same time

in

an exhausted developer which had been replenished.

It is impractical,

definitely unless

accumulates a

it is

however, to exhaust and replenish a developer filtered at

silver sludge

in-

frequent intervals, because the solution

and particles

picked up on the surface of the film.

of gelatin

which are apt

The developer may

to be

also acquire

fogging or staining properties.

The exhaustion products

of

development have a beneficial

effect in

so far as they reduce the fog density of a fresh developer which, in

many

The

fog in

may

cases, 11

"

A

be excessive and

is

apparent as veiled shadows.

Replenishing Solution for a Motion Picture Positive Developer " by

Crabtree and C. E. Ives.

/.

J.

I.

Soc. Mot. Pict. Eng. is, 627 (1930).

" The Maintenance of Negative Quality " by Amcr. Phot. 31, J. I. Crabtree. 874 (November 1937) et seq. " Report of the Committee on Laboratory Practice." /. Soc. Mot. Pict. Eng. 26,

345 (April 1936).


-

AND USING PHOTOGRAPHIC SOLUTIONS

INIIXING

a fresh developer

may

be overcome in three ways:

quantity of potassium bromide (0.5 gram per lon) or potassium iodide (o.oi

gram per

(i

by adding a small

c.

(30 grains per gal-

liter)

liter)

137

dram

of a

10%

solu-

by mixing a definite proold developer with the new; and c. by

tion of potassium iodide per gallon) or both; b.

portion (from 10 to

2 5')t

of

)

developing a few test or waste films in the fresh developer.

Exhausted

Fresh Fig. 66b

â&#x20AC;&#x201D; Comparison

of prints

times in fresh and exhausted (replenished)

shadow

â&#x20AC;&#x201D;

Replenished

from negatives developed

detail in the replenished developer

developers. is

for equal

The

loss in

surprisingly small.

The point at which a developer ceases to be useful depends on what is demanded of it. The time required to produce a definite contrast increases as the developer

when

used, and the developer ceases to be useful

is

the time required for this exceeds the

maximum

This

allotted for the developing operation.

is

of

time which can be

most importance

in

production laboratories where work must be finished according to a definite time schedule.

The by

its

life

of a motion picture developer

staining point.

the developing

life

is

most frequently determined

This frequently occurs long before the limit of

has been reached.^

Developer Troubles.

â&#x20AC;&#x201D; In order

to be able to explain the reason

any particular developer trouble, it is necessary to understand thoroughly what takes place when the ingredients are mixed in the wrong order or if any ingredient is omitted from the formula, and also the effect for

of chemical impurities.

trouble but the 12 "

M.

L.

It

is

unnecessary to indicate every possible

more important ones may be

listed as follows:

The Staining Properties of Motion Picture Developers

Dundon.

"

Trans. Soc. Mot. Pict. Eiig. No. 25, 108 (1926).

by

J. I.

Crahtree and


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

138

A.

The Solution

Is Colored.

when mixed, should be

colorless,

— As and

mixed with bisulphite, which contains to

colored, the developer should

In the case of a pyro developer

be suspected as being likely to give fog.

pyro

a general rule, the developer,

if

to the solution, although photographically If

B

combines with the

iron, the iron

form an inky substance which imparts a dirty bluish-red color

a pyro developer

solution,

is

it is

harmless.

mixed as two separate

solutions,

A

and B, the

which usually contains only carbonate and bromide, should

be perfectly colorless, though

if

carelessly

be colored brown by the presence of a

mixed

little

in dirty vessels

Any

pyro A.

it

may

stock solu-

tion containing pyro, however, usually has a faint pinkish color

when

freshly mixed.

— Either the developing agent or the carbonate was omitted during mixing. a white preC. The Solution Contains a White Sludge. — B.

The Solution Does Not Develop.

If

an AIQ developer on standing,

cipitate settles out of

Elon (or

result of the

precipitate

may

methanol, but too

if

much Elon

this is

probably a

developing agents) precipitating out.

allied

often be redissolved by adding this is not successful, then the

5%

wood

of

This

alcohol or

formula contains either

enough carbonate. If it is known that solution when mixed correctly and should the

or sulphite or not

the formula gives a clear

Elon precipitate out during mixing when the sulphite cipitate will usually redissolve

is

added, the pre-

on adding the carbonate or by heating

(not over i25°F.) (52°C.).

which

When a film or plate is immersed in a solution, any demay be lying on the surface is picked up by the gelatin

D. Scum. posit

coating and, unless removed by mechanical means, adheres thereto

throughout the processing and produces an image on the print. surface deposits are termed "

photographic solutions.

minute trace of scum

may

It will

Then

and

may

occur on

be, place a

drop of printer

s

all

Such

types of

how harmful a

ink on the surface

and pass a comb along the surface of the and remove it at once.

lay a sheet of paper on the surface

be seen to be covered entirely with streaky ink markings.

Scum on 1.

"

In order to appreciate fully

of a small tray of developer liquid.

scum

developer solutions

Organic matter

in the

may

be caused by:

water which

is

precipitated

by

the developer

chemicals and then rises to the surface. 2.

The presence

of calcium salts in the water,

which are precipitated

by the alkali in the developer. 3. Drops of oil or grease dropped accidentally onto the surface

of the


MIXING AND USING PHOTOGRAPHIC SOLUTIONS solution.

These are particularly apt

to occur

139

with developing machines

(Fig. 67). 4. Fungus growths or slimes on the sides of the tank, especially with wooden tanks. These become detached and float to the surface. 5.

Small particles of gelatin which are detached from the emulsion

warm

coating due to careless handling especially in

Fig. 67

â&#x20AC;&#x201D; Developer scum markings caused by

Such contaminations may be prevented by for

compounding the

a.

oil

weather.

and

grease.

the use of distilled water

solutions (see Chapter VI, page 106), b. the use of

water softeners (see Chapter \T, page no),

c.

cleaning and brushing the

powder (chloride of lime) followed by scalding so as to prevent slime formations (see Chapter XII, page 265), d. keeping the developer cool so that the gelatin is firm and not subject walls of the tanks with bleaching

to abrasion,

e. filtering,

and

/.

skimming the developer before use. daily rigid routine and may be

The skimming operation should be a accomplished by i. drawing the edge of the surface of the liquid or

skimming device E.

2.

suitable

(see Fig. 20, page 40).

The Developer Gives Fog.

by faulty mixing.

a sheet of blotting paper across

skimming the solution with a

It

may

â&#x20AC;&#x201D; Fog

is

the chief trouble caused

be a result of violation of the rules of mixing,

such as dissolving the carbonate before the sulphite, mixing the solution too hot, omission of the bromide, addition of too much carbonate or too little

sulphite, the use of

Developer fog

may

impure chemicals,

etc.

be defined as the formation of " a

deposited especially on those portions which receive

veil of silver

little

or no expo-


:

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

140

more or less to the total density Fog may be classified in two ways:

sure and which adds ^^

image."

Fog produced

1.

as a latent

of the developed

image before development and consisting

of the following types:

Emulsion Fog.

a.

— This

may

be a result of the presence of de-

velopable grains in the unexposed emulsion, or in fast emulsions

it

be only an increased susceptibility to chemical development fog.

may

Mod-

ern emulsions exhibit only a very slight tendency to emulsion fog.

Light Fog.

b.

— This

caused by accidental exposure to white

is

by the use of an unsafe light when handling photographic materials. Fog of a similar character may result from accidental exposure X-ray fog is usually distributed uniformly throughout the to x-rays. light or

emulsion layer whereas light fog

may

of the emulsion. c.

Fog from Vapors and

tine, benzol,

ether,

or

and

be confined to the surface layers

— Exposure

Gases.

to gases

to

vapors of turpen-

such as coal gas and hydrogen

sul-

phide renders the silver halide grains developable (see page 192).

Fog produced during development and

2.

types a.

— Several

Chemical Development Fog.

tain dyes, metallic sulphides,

when

and

consisting of the following

substances, notably cer-

strong fogging agents

tin salts, act as

present even in small concentrations in a photographic developer.

For example,

0.5

gram

of developer gives very

phide

is

(7 grains) of stannous chloride in a liter (quart)

bad

fog.

Under

formed by bacteria which

may

certain conditions

sodium

sul-

developer and reduce

live in a

the sulphite to sulphide.^*

The

bacteria seem to thrive in the slime which accumulates on the

sides of a tank so that the tank walls should be scrubbed thoroughly at

intervals (see section

on cleaning tanks. Chapter XII, page 265).

The

sulphide formed by this reaction can be removed by treating the developer with lead acetate in the proportion of

per gallon) of developer.

waste films

in the

It

may

also be

i gram per liter (60 grains removed by placing a few

developer whereby the silver halide emulsion reacts

with the sodium sulphide to form silver sulphide.

Another cause of chemical fog

sodium bisulphite

solution.

If a

is

the presence of zinc

galvanized pail

vessel, the zinc in the galvanized coating reacts

is

when mixing a

used for the mixing

with the bisulphite to

13 " The Fogging Properties of Developers " by M. L. Dundon and J. I. Crabtree. Amer. Phot. 18, 742 (1924). 14 " Sulphide Fog in Motion Picture Developers " by M. L. Dundon and J. I. Crabtree. Amer. Phot. 19, 96 (1925).


MIXING AND USING PHOTOGRAPHIC SOLUTIONS form sodium hydrosulphite, which

a powerful fogging agent.'

is

141

The

â&#x20AC;˘'^'

use of stoneware, hard rubber, stainless steel or enameled steel buckets

completely avoids trouble from this source.

Sometimes a developer may give excessive fog which has a yellowishbrown appearance on examining the film by transmitted light. When a developer gives fog, I

it

is

always desirable to take a portion (about

quart) and add lead acetate in the proportion indicated above and then

test for' fogging

recur

it

known b.

by developing a negative

w^as sulphide fog, but

as yellow stain

Aerial Fog.

if it

it is

and described below under

â&#x20AC;&#x201D;^With

" solvent fog."

certain developers, notably those containing

wet with developing solution

film

does not

a different type of stain

hydroquinone, a form of fog known as aerial fog

when

If the stain

therein.

persists,

is

sometimes produced

exposed to the

is

Such

air.^*^

modern motion picture developing machines, film in a tray, and in many cases where a parremoved from the developer for inspection.

conditions occur with some in the

development of

roll

tially

developed film

is

Traces of certain oxidizing catalysts, such as copper, favor the formation of this type of fog.

Theories as to

its

cause are rather vague but

it

may

be prevented by the addition of a desensitizer to the developer, such as pinakryptol green or phenosafranine in a concentration of one part in

two hundred

fifty

thousand parts of developer (see page 144).

Oxidized developers, particularly pyro, also tend to diminish aerial fog but the

life

MQ developer

of an

is

also shortened appreciably

addition of pyro so that the use of a desensitizing dye It is

is

by the

to be preferred.

somewhat anomalous that aerial fog should be produced while the is being oxidized and that oxidation products, when added to

developer

a fresh developer, should prevent aerial fog. is

Apparently, the aerial fog

produced by an intermediate reaction product which

ducing agent for c.

Solvent Fog.

â&#x20AC;&#x201D; This

type of fog

stain consisting largely of silver.

face

and

is

sulphite or

It

is

is

characterized as a yellowish

usually confined to the film sur-

removed by rubbing with the

absorbent cotton.

a strong re-

is

silver halide.

It

ammonia

is

fingers or a tuft of wetted

primarily a result of the solvent action of the

or hypo, or a combination of these, on the emulsion,

the developing agent reducing the dissolved silver salt back again to

yellow colloidal metallic ^">

J. F.

16

"

Amcr. 1"

M,

L.

Ross and

J. I.

silver.''

Pilot. 18,

J.

I.

Cral)tree.

742 (1924).

The Staining Properties Dundon.

Aincr. Phot. 23, 254 (1929). of Developers " by M. L. Dundon and

Crabtree.

The Fogging Properties

of Motion Picture Developers " by J.

Trans. Soc. Mot, Pict. Hug. No. as> 108 (1926).

I.

Crabtree and


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

142

The

precipitation of the colloidal silver

is

greatly accelerated

by the

presence of the sulphide ion (sodium sulphide) and, possibly, the sul-

phide forms specks of silver sulphide on the emulsion grains which act as nuclei for the silver precipitation.

A

concentration of sodium sulphide as low as

sufficient to

produce excessive stain

i

part in

i

million

is

presence of a sufficient quan-

in the

tity of silver solvent.

Since fine-grained emulsions are more soluble in a given concentration of a solvent than coarse-grained ones, the former are particularly sus-

The presence

ceptible to this type of fog.

of gelatin favors the precipita-

tion in a colloidal condition and, therefore, tends to change the color of

Experiments

the stain toward a dominant hue of longer wavelength.

have shown that the wavelength of the ticles is

absorbed by colloidal par-

equal to one-half the diameter of the particle.

In practice, therefore, yellow stain grained emulsions especially

if

if

is

apt to be encountered with fine-

and hangers are are not hardened in the

the films

the films

This results

dried with excessive heat. gelatin,

light

and sodium sulphide

insufficiently fixing

washed and

bath and are then

accumulation of hypo,

in the

because the unhardened

in the developer

and adheres to the hangers, while some hypo in this gelatin is sulphurized during drying and is sodium sulphide when carried over by the hangers to the

film tends to melt at the edges of the retained

converted to developer.

In some cases, the addition of potassium iodide 0.5

gram per

liter

thorough hardening, ing

in the

proportion of

prevents stain formation but the best preventative fixing,

and washing

of the films,

is

and thorough wash-

and frequent scouring of the hangers and cages.

The scouring

is

readily accomplished

by

boiling in a

10%

solution of

sodium phosphate, brushing, and washing. This development defect shown F. Mottle and Streaks.

tribasic

ure 68

is

â&#x20AC;&#x201D;

in Fig-

invariably caused by a lack of agitation especially in the case

of full exposures developed for only a short time.

form of streaks caused by

aerial oxidation or

It

may

appear in the

by the continuation

of

development locally during transfer of the film from one tank to another. It rarely occurs in automatic developing machines unless the film

and the solution are

insufficiently agitated.

Streaks are occasionally produced on

being retained between the jaws of a film inadequate.

On immersing

pounds flow down the

film

roll

films

by the

clip, especially if

the film in the developer, the

and cause fog (Fig. 69).

If

fixing

bath

washing

is

hypo com-

thorough wash-


MIXING AND USING PHOTOGRAPHIC SOLUTIONS

143

ing with brushing does not eliminate the trouble, the clips should be treated occasionally with a solution containing

ganate and

a

2%

sulphuric acid for

i^/(

solution of

Fig.

68

sodium

bisulphite,

— Developer

i

or

potassium perman-

i''y

minutes, rinsed, immersed in

2

and washed thoroughly.

mottle.

Fig.

69

— Fog

pro-

streaks

development by hypo retained between the jaws

duced

during

of film clips.

G. Airbells. film surface

The

— The

when

first

effect of a small

immersed

in the

bubble of

developer

is

trapped at the

air

shown

airbell prevents the access of the developer to the

therefore causes a white spot in the fixed-out

around the white spot of the developer

by

is

Figure 70.

The dark

circle

a result of oxidation fog caused by oxidation

the air bubble.

The dark streamer

result of these fogging oxidation products.

prevented entirely but are minimized into the developer.

fiilm.^*

in

emulsion and

They

if

the film

are rarely encountered

machines.

is

likewise a

Airbells cannot always be is

immersed slowly

when developing by

H. Miscellaneous Troubles. Stains on films, plates, and papers be produced in several ways in a developer as discussed in Chapter XI, page 230. Markings consisting of areas of heavier density than

may

the surrounding film are sometimes found on films or plates developed in 18 '

tree

and

Rack Marks and C. E. Ives.

Airbell

Markings on Motion Picture Film

Trans. Soc. Mot. Pict. Eiig. No. 24, 95 (1925).

"

by

J.

I.

Crab-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

144

hangers or on motion picture film developed on racks at the point where the film passes around the top and bottom slats of the rack. These markings are usually caused by retardation of development along the sides of the hangar or rack by the oxidized developer products and so-

dium bromide. They are prevented by thorough

agitation of the holder

or rack during development as well as agitation of the solution at the film surface.

Fig. 70

How

to

Mix

â&#x20AC;&#x201D; Airbell

Desensitizers.

markings on

â&#x20AC;&#x201D; Solutions

film.

of certain dyes

known

as

recommended for the control of developer fog, fog, and to permit development under compara-

desensitizers have been

and especially

aerial

tively brilliant safelight illumination.

The dyes may be used

in

two ways, namely:

before development in a concentration of about or

2.

they

may

I

part in 25,000 for desensitizing purposes or in a con-

part in 250,000 for preventing aerial fog.

I

Very few known Phenosafranine

many

is

desensitizers are stable

i

when added

quite stable but pinakryptol green

developers containing hydroquinone

greater than

as a preliminary bath

part in 5,000 or 10,000,

be added directly to the developer, usually in a concen-

tration of about

centration of

i. i

when used

is

in

to a developer.

precipitated in

a concentration

part in 50,000.

Desensitizing dyes are fairly expensive and for best results must be

used carefully, for with certain developers they are not as satisfactory as with other developers.

undertaken,

it

is

Before any extended use of these solutions

is

suggested that the user familiarize himself with the

characteristic properties of these substances.

A

comprehensive discus-

sion of the use of desensitizing dyes has been given

by M.

L.

Dundon


MIXING AND USING PHOTOGRAPHIC SOLUTIONS and

With modern high speed panchromatic emulsions

J. I. Crabtree.^''

which usually have

145

to be

handled

in

almost complete darkness,

it is

ad-

vantageous to be able to use a desensitizer (see Formula D-89, page 303).

The very

makes

it

dilute concentration in

difficult at first for

which these substances are used

The

an unskilled worker to prepare them.

recommended for their use: The most convenient method of preparing the dye solutions them up as a stock solution. Dissolve i gram (15 grains)

following directions are

to

is

in

make

500 cc

(i6 ounces) or preferably 1000 cc (32 ounces) of warm distilled water (about 125째 F.) (52째C.). The dye dissolves quite slowly and some-

These stock solutions represent

times the solution has to be heated. I

part in 500 and

i

part in 1000, respectively.

The

latter dilution is

most commonly used.

When

adding the stock solution of the desensitizer to a developer,

it

must be added very slowly; otherwise a precipitate may form, especially with developers containing hydroquinone. tion to a developer to

make a

i

To add

the

i

to

to 25,000 concentration of the

1000 solu-

dye

developer, take 40 cc (17 ounces) of the dye solution and pour

it

in the

slowly

with constant stirring into 1000 cc (32 ounces) of the ready to use developer.

If the

I

to

500 dye solution

is

used, take one-half as

much

or

20 cc (5 drams) to 1000 cc (32 ounces) of developer. For a preliminary bath of i to 5000 concentration, take 200 cc (6f ounces) of the i to 1000 dye solution and add water to make 1000 cc (32 ounces).

ACID RINSE BATHS AND ACID HARDENING BATHS During the development

of photographic emulsions, the gelatin

is

ren-

dered alkaline, and on transfer to the fixing bath, the alkali tends to neutralize the acid in the fixing bath.

An

excess of alkali destroys the hard-

ening properties of the usual alum fixing bath and tends to form a precipitate of

readily.

aluminum

Alum-acid

ther use.

It is

sulphite, thus rendering the bath unfit for fur-

fixing baths containing boric acid

important, therefore, to remove as

much

do not sludge so of the alkali as

possible before immersing the film or print in the fixing bath.

The is

simplest type of rinse bath between development and fixation

plain water, but this removes the alkali relatively slowly.

which chemically neutralizes the 19 "

alkali

is

A

bath

preferable, since this reaction

The

Trans. Soc. Mot. Pict. Eng. Effect of Desensitizers in Development." (1926) Amcr. Phot. 20, Xo. 37S, 438 (1926) also " Der Theorie und Praxis dcr Hypersensibilisierung " by K, Jacobsohn, Union Deutsche Verlags., Ber-

No.

z6, III

lin,

2931.

;

;


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

146

stops the progress of development.

With

certain types of automatic

developing machines, the use of an acid rinse cially

the film

if

is

exposed to the

the developer to the fixing bath.

An

very important, espe-

is

seconds in passing from

air for several

acid rinse in such cases introduced

immediately after removal of the film from the developer not only stops

development but also prevents the formation of stain

and insures that sludging does not occur

Two

types of acid rinse baths are in

3%

aerial fog

and developer

in the fixing bath.

common

use,

namely:

i.

2%

a

chrome alum, which might be termed a hardener rinse, since it both hardens the gelatin and neutralizes the alkali in the film or plate, and 2. a 1% or 2% acetic acid solution which is used for prints. In photofinishing work, about 0.5% acetic acid is sometimes added to the chrome alum solution since there is a tendency to carry more alkali There is into the rinse bath than in many other types of processing. or

solution of

greater danger of trouble from blisters, however, with this type of rinse

bath, especially during hot weather.

In case blisters are encountered, of acid, about

add only half the concentration

it is

better to

else

omit the acid entirely.

{Note: Blisters

may

0.25%, or

be avoided by using

An

developers containing Kodalk or borax as the alkali.)

acetic acid

bath containing sodium sulphate has also been suggested for negative materials (Formula SB-5, page 308).

This bath

is

recommended

for

use for photofinishing instead of an acetic acid-chrome alum solution.

An

acetic acid-sulphate bath does not

harden the gelatin but the

sul-

phate prevents swelling and softening while the acid stops development instantly.

The

solution works satisfactorily

up

to

8o°F. (26°C.) but

it

should not be used above that temperature or softening of the gelatin will

The bath keeps

result.

well without use.

It

should be replaced at

bath because the acid

least as often as the fixing

is

rapidly neutralized

and the sulphate concentration may become too low

to suppress the

swelling.

A 2^% bath

is

solution of sodium bisulphite

is

used occasionally for negative

The plain acetic acid rinse often called a " short stop " bath, especially by the photofinish-

materials

when hardening

ing trade.

A

is

unnecessary.

comprehensive discussion of the use of chrome alum rinse

baths has been given by Crabtree and Russell.-"

Hardening Rinse Bath for Films and tion of

chrome alum

retains

its

use, however, sulphite is carried into the bath 20

by

"

J. I.

Plates.

— A plain

solu-

With developer and

hardening properties indefinitely.

from the

Part Chrome AUmi Stop Baths and Fixing Baths Crabtree and H. D. Russell. /. Soc. Mot. Pict. Eug. 14, 483 (May 1930).

Some

Properties of

" I


MIXING AND USING PHOTOGRAPHIC SOLUTIONS

147

A

fresh

the presence of the sulphite reduces the hardening properties.

bath should be a blue-violet color by tungsten light when freshly mixed, but

ultimately turns yellowish-green with use.

it

It

then ceases to harden

and should be replaced by a jresh bath. The Importance of Agitation. A chromium scum composed of chromium hydroxide tends to be produced by the reaction between the chrome alum and the alkali in the developer carried over on the surface of the film. If the hardener rinse bath is reasonably fresh and the

â&#x20AC;&#x201D;

films are well agitated

When

when

first

immersed, the scum does not form.

the bath becomes old, however,

tion; the

it

tends to form even with agita-

bath should then be discarded.

Films or plates should always be wiped with wetted cotton after fixing

and washing and previous

to drying to

scum, because once the film thus formed.

Treatment

potassium citrate

is

is

dry

it is

of the film

sometimes

remove any possible traces of the very difficult to remove the stain

by bathing in a 5% solution of removing the stain although

effective in

care must be exercised in handling since this solution softens the gelatin

Chapter XI, page 253).

(see

Acid Rinse Bath for Papers. least 5 seconds in a

tive in checking

i

â&#x20AC;&#x201D; Prints

should be rinsed for at

or ih^^c acetic acid bath in order that

development and

in

be

effec-

preventing spots and stains

when

When

the prints are immersed in the fixing solution.

batches of prints It is

utes.

it is

it

handling large

desirable to extend the rinsing time to

i

or

2

min-

important to move the prints and to keep them separated

while in the acid rinse to insure that the solution has access to

all

parts

The bath should be tested with litmus paper at regular intervals and when it shows an alkaline test (blue litmus remains blue or red litmus turns blue) it should be replaced by a fresh bath. With of every print.

a I- or 8

by

1

2

-second drain after development, the equivalent of about twenty

0-inch prints

acetic acid rinse It is

may

be processed per

liter

(32 fluid ounces) of the

(Formula SB-i, page 307) before

good practice

to use a fresh

the acid rinse bath

is

becomes

it

bath for each batch of prints.

alkaline.

The

life of

determined by the quantity of alkali carried over

from the developer which depends on the quantity of developer retained

by

the print, the time of draining, and the quantity of alkali in the

developer.

Revival of Rinse Baths. a chrome alum rinse bath

is

â&#x20AC;&#x201D; For small

scale processing, revival of

not advisable because

economical to discard the solution and replace processing films on a large scale, however, the

it

life

it is

by a

simpler and more

fresh bath.

When

of the bath can usually


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

148

be extended so as to be twice or three times that of an unrevived solu-

Complete

tion.

details are given in the article referred to previously.-^

Revival of acetic acid or bisulphite baths for use with prints

recommended. alkaline

It is better to

and replace them with fresh ones.

not

is

when they become

discard such solutions

Typical formulas for hard-

ener rinse and acid rinse baths are given in Chapter

XIV, page 307.

FIXING BATHS The primary purpose remaining

of a fixing bath

is

to dissolve the silver salts

any photographic material after deThe chemical most commonly employed for this purpose is

in the gelatin layer of

velopment.

" hypo."

sodium thiosulphate, usually called

This substance has the

property of converting the silver halides to soluble complex thiosulphates of silver

and sodium which are removed from the gelatin

film during

washing.--

Fixing baths

may

be divided into two general classes as follows:

A. Non-hardening fixing baths. 1.

Plain hypo.

2.

Acid hypo.

B. Acid hardening fixing baths.

A. Non-Hardening Fixing Baths.

— A plain solution

quite satisfactory for fixing purposes provided

little

hypo

is

or no developer

is

of

The

carried over on the photographic material being processed.

centration of the hypo

is

con-

important because contrary to some general

impressions, the rate of clearing does not increase uniformly with con-

As shown by the curves

centration. in

Figure 71, which were prepared

in

connection with a motion picture fixing bath, the rate of fixing (meas-

ured in clearing times in minutes) increases as the quantity of

hypo

is

is

quite slow with a

(in the case of a positive emulsion) or of

emulsion), whereupon the rate of fixing tration of

5%

50%

to

concentration.

60%

tion.

40%

and

30%

(in the case of a negative

falls off

For average purposes, a all

difficulty is usually experienced

When

solution,

again until at a concen-

the bath fixes as slowly or even slower than at a

be taken as a rapid working bath for

No

5%

increased to a concentration of

30%

solution of

when mixing

a plain hypo solu-

mixing a quantity of solution in a tank, the filter

should be used (see page 32) and the

hypo may

types of material.

hypo dissolved

in

bag method

warm

water

(about i25°F.) (52°C.), because the temperature drops considerably

" Part I Some Properties of Chrome Alum Stop Baths and Fixing Baths Crabtree and H. D. Russell. /, Soc. Mot. Pict. Eng. 14, 483 (May 1930). 22 " Some Properties of Fixing Baths " by Trans, J. I, Crabtree and H. A, Hartt, -1

by

"

J. I.

Soc, Mot, Pict, Eng, No. 3S, 364 (1929).


MIXING AND USING PHOTOGRAPHIC SOLUTIONS while the hypo tion

is

on standing,

dissolving. this

If a

scum forms on

149

the surface of the solu-

should be removed by drawing the edge of a towel

or blotter across the surface, or

by using a skimmer device

(see Fig. 20,

page 40). TIME. TO CL-E^R MOTION PlCTURt

PANCHROMATIC

NEGATIVE. FILM.

TIME TO CLEAR MOTION PICTURE. POSITIVE FILM ^'t^

SO

100

l»0

5!>'f

SOO 600 %00 400 concentration: grams Na.2 SjOj 5HjO /liter solution

£00

700

Fig. 71

— Curves showing the time

and negative

films in

hypo

to clear

solutions

of

Eastman motion

picture positive

various concentrations at

different

temperatures.

A

stock solution of plain hypo should preferably be allowed to stand

overnight before use in order that any foreign matter

may

settle

out or

rise to the surface.

A wooden

cover

made

in the

manner described on page

71

(Fig. 36)

and treated with several coats of a nitrocellulose lacquer, such as Eastman Lacquer No. 5119, makes a satisfactory cover for placing on a stock solution hypo tank. A somewhat more expensive but equally satisfactory cover for a hypo tank may be made of 18-8 stainless steel containing about 3% molybdenum.

A plain hypo fixing bath, however, is seldom used because it rapidly becomes alkaline from an accumulation of alkali carried over by prints and films from the developer, and this tends to soften the gelatin, while the image continues to develop in the fixing bath, so that if two prints or films stick together,

more development takes place

contact, causing uneven development.

If the

bath

is

at the point of

acid, however, the

acid neutralizes the alkali in the developer carried over, thus preventing

unevenness.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

150

In order to be able to mix an acid fixing bath intelligently sary to understand a

Hypo can

be

little

made by

boiling together

sulphur until no more sulphur solution, sulphur

is

milk of sulphur.

it is

is

sodium sulphite and flowers of If acid is added to a hypo

dissolved.

again liberated, forming a milky solution

If

neces-

about the chemistry of the acid fixing bath.

sodium sulphite

is

present, however,

known

as

any sulphur

to come out of solution combines with the sulphite to form more hypo and the solution therefore remains clear. This sulphur if precipitated cannot be redissolved by adding sodium sulphite to the milky solution except by boiling, while on standing it is

which tends

All plain acid fixing baths

apt to settle on films or prints as a scum.

by adding an acid salt such as sodium bisulphite or potassium metabisulphite to the hypo solution or by using sodium sulphite and some weak acid which has a much lower tendency to decompose hypo than stronger acids like sulphuric acid. Practical hints therefore are prepared

on mixing acid

Do

1.

hypo

fixing baths are as follows:

not add the bisulphite or acid sulphite solutions to the

solution.

The

(i8°-2i°C.) or the hypo

On

2.

will turn

warm

when mixed (65°-70°F.)

solutions should be cool

milky.

keeping, an acid hypo solution gradually becomes milky. a stock solution of the sodium bisulphite,

To

etc.,

should be

kept and added to the plain hypo stock solution as required.

For gen-

prevent

this,

ounces (45 cc) of a 50% sodium bisulphite solution is added to 32 ounces (1000 cc) of a 35% hypo solution. If any considerable excess over this quantity is added the hypo rapidly turns milky,

eral purposes, i^

especially in

warm

weather, owing to the liberation of sulphur.

Plain acid hypo solutions are not used very tion of

alum because

of the ease with

much without

the addi-

which they sulphurize and their

entire lack of hardening properties. If the

temperature of the processing solutions can be maintained at

65° to 70°F. (18° to 2i°C.) and

if

ample drying time can be allowed so

that relatively cool drying air can be used, a non-hardening fixing bath

containing hypo, sulphite, and bisulphite

The

is

satisfactory.

bisulphite serves to keep the bath acid

the sulphite prevents precipitation of sulphur

vious to use at too high a temperature. acid

and prevent

stains while

the bath

stored pre-

if

is

The bath should be maintained

by reviving with a 25% solution of sodium bisulphite at intervals machine processing, by allowing this reviving solution

or in the case of

to flow into the tank continuously during use.

An

alternative

method

of revival consists in passing sulphur dioxide


MIXING AND USING PHOTOGRAPHIC SOLUTIONS

151

Although this is a fairly efficient procedure, there is danger of accidental escape of the suffocating gas into the atmosphere gas into the bath.

room

of the

so that

practical application

its

of questionable value.

is

A typical non-hardening fixing bath is Formula F-24 page 312. A 2% solution of potassium chrome alum may be used as a hardener rinse bath in conjunction with the

above

fixing bath, although

be desirable to reduce the bisulphite concentration liter

to 10 or 15

it

may

grams per

(150 or 225 grains per quart) because acid would be carried into

the fixing bath from the

chrome alum

rinse bath.

Acid Hardening Fixing Baths.

B.

by adding

are prepared

to

â&#x20AC;&#x201D; Acid hardening

fixing baths

hypo an acid hardening solution which usually

contains the following ingredients: 1.

A

preservative such as sodium sulphite or sodium bisulphite.

latter acts as a preservative in

two ways:

it

The

prevents the formation of

sulphur by the action of the acid on the hypo, while

it

also prevents the

developer carried into the fixing bath from oxidizing and turning brown. 2.

An

acid such as acetic, boric,

3.

A

citric, lactic,

malic, maleic, sulphuric,

which stops development.

tartaric, etc.,

hardening agent such as potassium alum, potassium chrome

alum, or formaldehyde.

A

comprehensive paper on the chemistry of fixing baths has been

published by given herein

J. I. is

Crabtree and H. A. Hartt,-' and '

H. D. Russell which deals with chrome alum 1.

It is

much

taken from this paper and another by

imperative

when compounding an

of the material

J. I.

Crabtree and

fixing baths.-*

acid fixing bath to have a

quantity of free acid present in order to prevent discoloration of the bath

by developer reaction products, and

also to prevent precipitation of the

hardening agents by the alkali of the developer.

Since free acid tends

hypo with liberation which will counteract this substance must be added

of free sulphur,

some

Two

types

to cause decomposition of the

reaction.

of substances are effective, namely: a. the alkaline sulphites, such as

sodium

sulphite,

and

b.

the alkaline salts of organic acids, of which so-

These latter substances tend to is a typical example. " buffer " or reduce the hydrogen ion concentration * or pH of the acid

dium acetate

employed below the 2. 23

Practically "

Some

all

limits at

which sulphur

is

precipitated.

of the commercially available solid organic acids

Properties of Fixing Baths " by

J. I.

Crabtree and H. A. Hartt.

Trans.

Soc. Mot. Pict. Eng. No. 38, 364 (1929). 24 "

by

J. I.

*

Some Properties of Chrome Crabtree and H. D. Russell.

Alum /.

Stop Baths and Fixing

Bathsâ&#x20AC;&#x201D;

Part II

Soc. Mot. Pict. Eng. 14, 667 (June 1930).

For a brief discussion of the meaning of

this term, see

page 117.

"


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

152

yield with tive

aluminum

salts,

hardening agents.

complex aluminum ions which are not

erally efficient acid for use in fixing baths containing potassium

Sulphuric acid, which

the hardening agent.

effec-

Acetic acid has been found to be the most gen-

is

a mineral acid,

is

alum as the most

chrome alum. Of the acid salts, sodium bisulphite and potassium metabisulphite are the best known, but these substances are not suitable for use with acid hardening fixing baths containing alum because the reserve acidity of these salts is insufficient to prevent precipitation of aluminum sulphite

satisfactory for fixing baths containing

on the addition of

alkali.

Hardening agents for use with gelatin consist of two types, temporary and permanent hardeners. The former class, of which sodium sulphate is an example, merely suppress the swelling and raise the melt3.

ing point of the gelatin while

These substances are used essing of materials

when

it is

in contact

with the hardening solution.

chiefly in conjunction with the tropical proc-

it is

necessary to handle them at temperatures

above 75°F. (24°C.) (see Chapter VIII). gelatin, rendering

Permanent hardening usually tans the

it

incapable

washing chromium, and

of swelling except to a very limited degree during subsequent in the

normal manner after

fixing.

The

salts of iron,

aluminum exert the most effective hardening action on gelatin. Salts of aluminum are perhaps the most satisfactory because they are colorless, readily soluble in water, and do not form colored compounds with

common

the

developing agents, while they give satisfactory hardening

provided the wash water temperature tain

aluminum

salts,

aluminum

is

not above 8o°F. (26°C.).

Cer-

chloride, for example, tend to hydrolyze

aluminum hydroxide when dissolved in aluminum and sodium or potassium sulalums form a clear solution and are to be preferred.

and form a white precipitate

of

water, but the double salts of

phate called

Formalin, quinone, and developer oxidation products also tan gelatin

but only is

in alkaline or neutral solution

and

their application therefore

limited.

Acid Hardening Fixing Baths Containing Boric Acid. fixing baths containing acetic acid,

and hypo, the maintained

is

pH

— With

potassium alum, sodium sulphite,

range * throughout which satisfactory hardening is A fresh bath has a pH value of about 4.2

rather limited.

and a used bath, which has precipitated an aluminum sulphite sludge, about 4.8. When the acidity varies much above or below this range, the bath ceases to harden. *

The

pH

of water

is 7.0.

For a discussion of the meaning of the expression

"

pH,"

see p. 117.


MIXING AND USING PHOTOGRAPHIC SOLUTIONS If boric acid is

added

bath of

to a fixing

range over which good hardening exists the sludging tendency

this type,

pH

extended considerably and

is

greatly diminished.-''

is

however, the

153

A

bath of

this

type has

ErrccT or exh«kustion on the: ha.roe.ning. PROPERTIEIS AND pH VA,l_UES OF" VARIOUS riXltSG. BATHS. (0-\a F--Z

FILING

OE-VEI-OPERl

BATH WITHOUT

210

AGIO

REVIVAL

4.5 6.0

ISO u:

6.5

ul

s = si_udg.e:

U 110

I

tf

F-Z

a

I

F-tX\NC»

S.O-

BATH WITH

u o

ACIO RE.V1VA\_

-^N^-.V4^«^N

R R R R R ^ 2 '80 n 160 (J

Z

UO BORIC ACIO FIXING. BATH WITHOUT ACIO RE.VIVAl_

U JZIO

4.6

180 160

liO

100 ZOO 300 400 zoo 300 400 6 MIN. 0-l<i AND FIKEO 10 MIIM.

lOO

Fig. 72

— Hardening

properties and useful

life

60

of

boric acid vs. older type of acid-alum fixing bath.

a a

pH pH

sity

value of about 4.2 value of about 6.0.

fresh and the hardening is maintained to Because of their much lower sludging propen-

when

and excellent hardening

acid are

recommended

characteristics, fixing baths containing boric

and plates

for films

bath which does not contain boric acid.

and the

life in feet of film fixed

Chrome Alum Fixing

sludge in

type of

characteristics

per gallon are shown in Figure 72.

Baths.

— Chrome alum

or

chromium potas-

hardening agents used for tanning it does not readily precipitate a that advantage It has the on the addition of developer baths fixing sulphite acid-sodium

sium sulphate was one of the gelatin.

in place of the older

The hardening

first

baths containing aluminum alum. If the bath once precipitates a sludge of chromium hydroxide, however, the solu-

as

is

the case with

many

tion should be discarded, as there

the film and

producing a stain

is

danger of the precipitate settling on is very difficult to remove.

which

25 " An Improved Potassium Alum Fixing Bath Containing Boric Acid " by H. D. Russell and J. I. Crabtree. /. Soc. Mot. Pict. Eng. zi, 137 (August 1933)-


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

154

Chrome alum

fixing baths are capable of

hardening gelatin to a greater

degree than potassium alum fixing baths but the chrome alum baths,

compounded, lose their hardening powers rapidly either Sodium sulphite, although necessary to prevent

unless properly

with or without use.

decomposition of the hypo, tends to destroy the hardening properties of the

chrome alum.

insures a longer

about

3

:

Usually a concentration of chrome alum of about

life

by weight

5

and the sulphite

to

of chemicals for

alum

maximum

Fixing Baths Containing Potassium Alum. fixing baths containing

The degree

be

keeping properties.

— The

relative merits of

potassium alum as compared with those with

chrome alum may be summarized 1.

3%

ratio should preferably

of hardening

as follows:

may

be adjusted precisely between 120°

and 2i2°F. (49° and ioo°C.). 2.

The hardening

on standing without

properties of the bath do not change appreciably use.

Scum is readily detected and can be removed if dried on the film. There is no danger of staining the film at high temperatures. Fixing Baths Containing Chrome Alum. i. Have great hard3. 4.

ening ability when fresh but lose this rapidly on standing with or without use. 2.

The type

of hardening

subsequent treatment and conditions.

It

is

is

very rugged and

useful

is

when

destroy by

not possible to adjust precisely the degree of hardening

obtained between values of 120° and 2i2°F.

alum baths

difficult to

processing film under tropical

either

do not harden at

all

In other words, chrome

or produce a melting point above

2I2°F. 3

Although the scumming tendency

baths, sludge precipitation is

very 4.

difficult to

The

remove

is if

excessive

is

less

than with potassium alum

when once

started and the

scum

allowed to dry on the film.

alkalinity of the film affects the hardening greatly.

in the gelatin if the concentration of the chrome alum is too high. For general use with films and plates at normal temperatures and where it is desired to keep the bath several weeks, an acid fixing bath containing potassium alum and boric acid is preferable. Chrome alum fixing baths are quite satisfactory, however, for use where maximum hardening is required, especially under tropical conditions. Such baths should be discarded every few days if the most effective hardening is to 5.

Green stain forms

be realized.

The

addition of boric acid to chrome alum baths does not extend the


MIXING AND USING PHOTOGRAPHIC SOLUTIONS hardening

life

when

pH

or increase the sludging

pH

bath has a

A

life.

fresh

chrome alum

pH

value of about 3 and hardens well until the

155

fixing is

3.8,

the hardening begins to drop until the bath ceases to harden at a

A

of 4.5.

sludge

is

usually precipitated at a

pH

pH).

for a discussion of the term.

The Useful Properties

of 5 (see page 117

—^A satisfactory acid

of a Fixing Bath.

^

hardening fixing bath should have certain properties, namely: a fairly

minimum tendency

rapid rate of fixation, good hardening, a ing blisters, a long sludging

The time

for fixation

is

and

life,

a long useful

for

produc-

life.

usually taken as twice the time for the milki-

ness or opalescence of the unreduced silver salts to disappear.

depends on the strength of the hypo (30 40% idly), the photographic material tested (portrait films

hypo

to

fixes

fix

This

most rap-

comparatively

slowly, usually requiring 3 to 6 minutes to clear, whereas lantern slides fix

rapidly, clearing in 30 seconds to

solution (65°F.

is

i

minute), the temperature of the

recommended), and the degree of exhaustion

of the

solution.

by a large number of factors. alum is required to give the necessary A certain minimum quantity of may produce too much hardening hardening, while an excess of alum and induce brittleness. Normal potassium alum fixing baths are care-

The hardening

properties are influenced

compounded to give a hardening of 130° to i8o°F. (54° to 82°C.), determined by immersing a strip of the fixed and washed film in water,

fully

heating the water slowly on an electric hot plate (about 5°F. rise per

minute) and reading the temperature at which the gelatin flows away from the support (see apparatus for melting point test. Fig. 73, page 156).

The hardening produced by

the bath depends on

factors such as the emulsion used

and the

and

and the temperature

of all solutions;

factors including the time the film

given in

all

baths,

" certain " fixed

pH of the film, the composipH value of these solutions,

bath and the

tion of the rinse bath

fixing

a.

and upon is

b.

a number of variable

in the fixing bath, the agitation

and the time of washing.

For

maximum

hardening

using a 5-second rinse in water between development and fixation, and

washing 20

to

fixed 15 to 20

40 minutes minutes

in

running water after fixation, film should be

in either fresh or partially

exhausted acid harden-

ing fixing baths.

Since a chrome alum fixing bath loses

veloper better, a

is

carried into the bath,

chrome alum hardener

it is

rinse

its

hardening properties as de-

important to use a water rinse

between development and

or,

fixation.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

156

A

fixing bath should not

produce

page 167).

films or papers (Fig. 75,

blisters in the gelatin coating of

If the acidity of the

bath

is

too high,

the formation of carbon dioxide gas proceeds too rapidly with the addition of a carbonate developer to the fixing bath to

form within the gelatin layer which

finally

and gas pockets are apt blisters. De-

break causing

velopers prepared with borax or with Kodalk do not release any gas

when added

to the fixing

bath and

Apparatus

Fig.

blister

formation

is

eliminated.

for melting point determination.

A

good

life of

fixing

the bath

to 2i°C.).

bath should not sludge or turn milky during the useful at normal temperatures of 65° to 70°F. (18°

when used

There are two

different

ways

in

which a

fixing

bath

may

precipitate a sludge, as will be discussed subsequently under " Trou-

Changes in temperature of the fixing bath affect the rate of fixaand the useful life of the solution. For example, if a film requires 95 seconds to clear at 65°F. (iS^'C.) it would take about 60 seconds to

bles."

tion

clear at 85°F. (29°C.), but

it is

dangerous practice to allow the tempera-

much above 7o°F. (2i°C.) because the solution sulphur. Under tropical conditions when high tem-

ture of the bath to rise is

apt to precipitate

peratures prevail,

it

is

within this limit without

obviously impossible to keep the temperature fixing

bath must

for tropical processing,

where the

artificial refrigeration,

and the

always be replaced oftener.

A

different technique

must be used


MIXING AND USING PHOTOGRAPHIC SOLUTIONS abnormal swelling

secret lies in preventing

swollen,

is

it

almost impossible to reduce

157

of the gelatin, for once

and

it

to

handle the

it is

In-

film.

formation on this subject will be found in Chapter VIII, page 178.

Typical formulas for potassium and chrome alum fixing baths are

found on pages 309-313 of Chapter XIV.

Mixing Fixing Baths and Stock Hardener Solutions.

It

is

often convenient to prepare a concentrated hardener for use as required.

The formula

for

such a stock solution for making a fixing bath for papers

(Formula F-i)

as follows:

is

Acid Hardener Stock Solution

[F-la] Metric

Avoirdupois

Water (about

Sodium

125° F.) (52° C.)

ounces ounces ounces

1700.0 cc 240.0 grams 750.0 cc

8

ounces ounces

210.0 cc 240.0 grams

1

gallon

56

Sulphite, desiccated

8

Acetic Acid (28% pure)

24

or Glacial Acetic Acid (pure cone.)

6%

Potassium Alum Cold water to make *

To make 28%

acetic acid

from

4.0 liters

glacial acid, dilute 3 parts of glacial acid with

8 parts of water.

For of a

use,

25%

add i part of cool stock hardener solution slowly with hypo solution.

To make up above.

stirring, to 4 parts

cool

the hardener, dissolve the chemicals in the order given

The sodium

sulphite should be dissolved completely before add-

After the sulphite-acid solution has been mixed thor-

ing the acetic acid.

oughly, add the potassium alum with constant stirring.

If the

hypo

is

not thoroughly dissolved before adding the hardener, a precipitate of

sulphur

is

likely to form,

which

it is

not possible to redissolve, and the

solution will have to be discarded. It is

sometimes recommended

to reverse the order of

hardener, namely: dissolve the alum phite, but the

alum

dissolves

first,

add the

more readily

acid,

mixing of the

and then the

in the acetic

sul-

acid-sodium

sulphite solution.

Another method tions, cool,

is

to dissolve the

add the acid

If the order of

mixing

phite, a white sludge of

is

reversed and the alum added

aluminum

with difficulty when the acid

is

milky after mixing and a sludge sufficiency of acid

;

that

alum and sulphite in separate soluand then add the alum.

to the sulphite solution,

is,

sulphite

added.

is

Therefore,

settles out, this is

the acid used

was

much alum or sulphite was added. Fixing Baths Containing Boric Acid.

or too

cipitation of

an aluminum sulphite sludge

is

first

to the sul-

formed which dissolves if

due

the hardener

is

to a relative in-

either not

up

to strength

— The tendency

greatly minimized

for preif

boric


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

158

acid

is

added

potassium alum acid fixing bath such as the one pre-

to a

pared from the following formula. the bath

is

extended greatly and

film surface

The

much

is

less

Furthermore, the hardening

life of

propensity to deposit a scum on the

its

than for baths which contain no boric

acid.-''

following formula represents a typical bath containing boric acid.

[F-5]

Acid Hardening Fixing Bath for Films and Plates Avoirdupois

Water (about

Metric

13 2

ounces ounces ounce fluid ounces

3}4

drams

125° F.) (52° C.)

20

Sodium Thiosulphate (Hypo) Sodium Sulphite, desiccated *Acetic Acid, 28% pure

8 '2

600.0 cc 240.0 grams 15.0 grams 47.0 cc

or

Glacial Acetic Acid (pure cone.) tBoric Acid, crystals

...

}4 J^

Potassium Alum Cold water to make

32

13.0 cc 7.5 grams 15.0 grams

ounce ounce ounces

1.0 liter

Dissolve chemicals in the order given. *

To make 28%

acetic acid

from

glacial acid, dilute 3 parts of glacial acid with

8 parts of water.

Pow-

t Crystalline boric acid should be used when mixing the above formula. dered boric acid dissolves only with difficulty and its use should be avoided.

A Chrome Alum Fixing Bath. Fixing baths containing chrome alum usually have very good hardening properties when freshly prepared but, unless properly compounded, tend to lose their hardening characteristics with or without use after several days. A chrome alum fixing bath having quite satisfactory hardening properties

[F-23]

Chrome Alum Solution

to

Solution

B

make

Water

Sodium

Sulphite, desiccated

*Sulphuric Acid,

pounds

1

96

ounce, 290 grains ounces

20

ounces

600.0 cc

grains

20.0 grams 160.0 cc 128.0 grams

4M 32

ounces ounces ounces

fluid

5 ..

Directions: Solution B by adding the chemicals in

Then add Solution B slowly oughly. If Solutions

A

To prepare 5%

to

Solution

and B are not

cool

sulphviric acid,

A

960.0 50.0

3.0 liters

1.0 liter

and cool the order given and cool

Dissolve the constituents of Solution

Mix

grams grams

2

290

5%

Potassium Chrome Alum. Water to make

*

Metric

Avoirdupois

Sulphite, desiccated

Water

the following:

Fixing Bath for Films and Plates

A

Hypo Sodium

is

A

to 7o°F.

(2i°C).

to 7o°F. (2i°C.).

while stirring the latter solution thor-

when mixed,

the bath will sulphurize.

add one part by volume of pure concentrated

sulphuric acid slowly to 19 parts by volume of cold water, and mix carefully with stirring. The acid must he added to the zvater and not the water to the acid, other-

wise the solution will boil with explosive violence, and or face, will cause serious burns. 26 "

An Improved Potassium Alum

Russell and

J. I.

Crabtree.

/.

if

spattered on the hands

Fixing Bath Containing Boric Acid " by H. D.

Soc. Mot. Pict. Eng. 21, 137 (August 1933)-


MIXING AND USING PHOTOGRAPHIC SOLUTIONS

159

deep tank and the hypo bath is not stirred adequately, the chrome alum solution will tend to float on top of If the solutions are

mixed

in a

hypo solution and sulphurization

the

not be stored as a stock solution as It is possible to revive the

useful

by the addition

life

Fig. 74

it

is

— Lantern

will lose its

— After a

bath has been mixed,

fixing

The

The

be determined as follows:

until the

it

recommended are

tests

rate of fixation

place

bath solution on a strip of film or plate and allow

fixing

its

time of fixation.

slide test of

the rate of fixation and the hardening ability.

may

should

above bath several times and extend

should be tested before being put into use.

to clear

B

hardening properties.

of dilute sulphuric acid.-'

Testing Fixing Baths.

or time

Solution

apt to occur.

some

of the

this to

stand

milky emulsion under the streak becomes clear or dissolved

Then immerse

(Fig. 74).

the strip in the fixing bath and determine the

time required for the streak to disappear, which indicates that silver salts

all

the

The time found should then be commade under standard conditions with a bath known to

have been dissolved.

pared with a

test

be of satisfactory composition.

The degree

of hardening test should be

made

in

a

manner

similar to

the hardening test described previously on page 155.

The time and

I),

of fixing, therefore, depends

upon

a.

the " time to clear,"

the time required to attain the desired degree of hardening.

Ob-

viously, the time for h. should always be greater than the time for a. -'

by

"

J. I.

Some Properties of Chrome Crabtree and H. D. Russell.

Alum Stop /.

Bath.s

and Fixing Baths

— Part

Soc. Mot. Pict. Eiw. 14, 667 (June 1930).

II

"


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

160

Effect of

— With

Time and Temperature on

the Rate of Hardening.

baths containing potassium akim and having a

pH

below

such as the older type of baths without boric acid, the hardening creases rapidly during the

first

few minutes after immersion and then

tends to become almost constant after 10 minutes in the bath.

pH

baths which have a

5,

in-

Fixing

of 5.0 or above, such as a partially exhausted

potassium alum bath containing boric acid, harden more slowly during the

first

few minutes but continue

hardening throughout

to give greater

the time of bathing.

The

rate of hardening increases generally with temperature unless the

swelling of the gelatin, previous to fixation, becomes excessive.

Effect of Temperature and Agitation on the Fixing Time. The temperature of a fixing bath, although of less importance than that of the developer, should receive attention.

For instance, with

roll film,

lowering of the temperature from 75°F. to 55°F. (24° to i3°C.) doubles

For

the time of fixation. to

efficient

working, therefore,

it is

very necessary

keep the temperature of the fixing bath approximately the same as Agitation of the film in the fixing bath also speeds

that of the developer.

up

shown

fixation at various temperatures as

in

Table

The data

4.

apply only to a particular emulsion.

TABLE

4

Effect of Agitation and Temperature on the Time of Fixation With Without

...

Temperature

it

Agitation

6o°F. (i5°C.)

15 Min.

20 Min.

65°F. (i8°C.)

12

Min.

16 Min.

70°F. (2i°C.)

10 Min.

13

75°F. (24°C.)

Min.

7

The Useful Life used

a

Agitation

5

of Fixing

becomes exhausted as a

The

ing out the emulsion. in,

phurization

With

life.

result of

a fixing bath

is

performing useful work

acidity of the bath

although at

developer carried

Baths. — As

Min. Min.

first this

is

being in fix-

being reduced by the

tends to favor a longer sul-

use, however, the usual

potassium alum-acetic

acid-sulphite-hypo solution finally reaches a point where a sludge of

aluminum the

first

sulphite

is

precipitated, rendering the bath useless.

During

stages of use of the usual bath containing potassium alum, the

hardening properties increase slightly, after which they fall off rapidly. As noted previously on page 157, the hardening range is extended and


MIXING AND USING PHOTOGRAPHIC SOLUTIONS the sludging tendency greatly diminished

when

boric acid

added

is

161

to

an

alum-acetic acid bath.

A

bath

fixing

is

usually exhausted

it

if

froths at the surface or

if it

becomes milky or sludges throughout the solution. The bath may also fix so slowly that there is a danger of removing the films or prints be-

When

fore they are completely fixed.

the time of clearing for a fixing

film exceeds lo to 12 minutes, the bath should be discarded.

In order to insure thorough fixation to

remain

in the fixing

customary

it is

to allow the film

bath for twice as long as the time required for

the emulsion to clear.

A

satisfactory acid hardening fixing bath should

fix

completely the

equivalent of eighty to one hundred 8 by lo-inch films or plates per 4

liters (gallon)

before the bath should be discarded.

should be rinsed for at least fixing.

5

All films (plates)

seconds in water between developing and

During hot weather, the use of an acid hardening is recommended.

rinse

(SB-3,

page 307)

A

satisfactory fixing bath for papers should fix the equivalent of

about sixty 8 by lo-inch prints per 4 liters (gallon) provided a thorough rinse (not less than 5 seconds) in water precedes fixation. Or if a twoor three-minute immersion in a suitable acid rinse bath (SB-i, page

307) is given between development and fixation, the equivalent of one hundred and twenty 8 by lo-inch prints may be fixed per 4 liters (gallon).

The chrome alum bath given life

as the potassium

alum

bath

fixing

is

before has about the same useful fixing

alum bath. The hardening

much

life

of the usual

chrome

shorter, however, because the hardening

falls

and the acid two or

off quite rapidly as a result of the reaction between the sulphite

chrome alum, unless the bath

is

three times during

life.

useful

its

revived Its

by

the addition of

hardening power will be main-

tained for only about two weeks regardless of

how

the hardening can be held up for a longer period

For maximum hardening, therefore,

it

is

by thoroughly washing the

by adding

films

used, but

suitable revival.

necessary to maintain the

acidity of the bath close to the original value either

by

little it is

and

this

can be insured

between developing and

fixing, or

further quantities of acetic or sulphuric acid to the bath at

definite intervals.

The

by chemical analysis

add can be determined only by keeping a record of the quantity of films

precise quantity to

or

fixed in the bath.

Attempts

to revive the fixing-out properties of the

baths by further

additions of hypo are not generally to be recommended.

Usually by


162

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

the time the bath

and get the

When

last

is

when

When

excessive.

it

muddy and

it is

â&#x20AC;&#x201D;A

Fixing Bath.

deposits a sludge or

using machines there

economy

false

to try

is

a

fixing

when

bath should be

the time of fixation

maximum

permissible time clear-

equal to one-half the time required for the film to pass through

the fixing bath.

Maximum

at a temperature of 65^ F.

Some workers make

efficiency

is

obtained only when the bath

is

(18-C).

a practice of testing the specific gravity of their

baths, thinking that this 5.

it is

and the baths should therefore be renewed when the

for fixation

ing time

exhausted

to Discard the

discarded either is

is

ounce of work out of the bath.

is

an index of the degree of exhaustion.

Table

however, should convince the most skeptical that the specific gravity

readings of a fixing bath bear very for film to clear.

under actual

A

change

test conditions

gravity of the bath.

Of

little

relation to the time required

in the clearing

time from

2

produced no change whatever

course,

if

to 12

minutes

in the specific

a large quantity of water

is

carried

over by the films, the specific gra\aty will decrease but not necessarily in

proportion to the degree of exhaustion.


MIXING AND USING PHOTOGRAPHIC SOLUTIONS The degree which it

it

of exhaustion of a fixing bath

When

out the emulsion.

fixes

should be discarded.

by a

that required

With papers

Usually,

is

when

difficult to

make

the emulsion has practically the

is

rate at

too slowly,

fix

the time of fixation

fresh bath, the solution

it is

shown by the

best

a bath begins to

163

twice

is

considered exhausted.

a " time of clearing

"'

test

because

color as the paper stock, but

same

it is

possible to determine the fixing efficiency of such baths indirectly.

The Sulphide

Test.

— Cut a number

posed paper for which the fixing bath

of i-inch strips of the unex-

i

the time

it

minute, another

is.

fix

has been fixed, remove them from the fixing bath at the end

of the given time,

merse the strips

Two grams liter

2

these in

one strip 30 seconds, minutes, and so on. Note on each strip

the bath for var\-ing lengths of time; that

another

Immerse

to be used.

is

and wash thoroughly

in a

weak (about 0.2%

)

— about

i

Then im-

hour.

solution of sodium sulphide.*

(30 grains) of sodium sulphide by weight dissolved

(32 ounces) of water will

make up

in

one

a solution of the correct strength.

{Warning: The sulphide solution should be kept away from the develbad chemical jog.)

oper, as a trace of sulphide in the developer will cause

The presence

of very

minute quantities of unfixed

silver in the

emulsion

of these strips will cause a brown or yellowish-brown stain to appear

when

the strip

placed in the sulphide solution.

is

In this way, the rate or speed of fixation of a fixing bath

termined, because a strip treated by this method

is

may

be de-

completely fixed

if

In actual practice, howit does not discolor in the sulphide solution. ever, the time for complete fixation should be longer than that shown

by the

test, since

the test represents ideal conditions.

of prints are being fixed at once, the time should be

The best way make the test as is

of arriving at a

margin of safety

outlined above for a fresh bath.

When

still

for a fixing If a partly

then tested and found to require twice as long to

a

number

longer.

bath

is

to

used bath

fix, it is sufficiently

exhausted to be discarded as unsafe for use.

An fixing

alternative test for detecting

bath has doubled

is

lantern slide in the fresh as

to

when

the

time to clear

"'

for a

paper

determine the time to clear for a slow

compared with the used bath

(see page 159

and Fig. 74). The rate of fixation of a lantern slide emulsion is somewhat slower than that of developing-out papers but the ratio of the clearing time of a fresh and exhausted bath is similar in the case of paper and lantern *

The

slide emulsions.

sulphide immersion should be done, preferably, in another room than the that accurate comparison of the strips may be

darkroom and before a window so facilitated.


:

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

164

Under fix

and with

ideal conditions

agitation, a fresh fixing bath will

a print completely in 30 seconds to

i

minute (as measured by the

sulphide test), and a partially exhausted bath will require from

i

to 3

minutes, depending on the degree of agitation and the quantity of prints

minimum

In practice, however, a

previously fixed therein.

of 10 minutes should be adopted because under practical tions prints

prints

fixing time

working condi-

do not always receive individual treatment, and when the

one on top of another, a stop bath and a fixing bath do not

lie,

The time

have thorough access to the emulsion.

of fixation should be

such that even in the case of prints which stick together the fixing bath has free access to every part of the print for at least 3 minutes. time of 10 minutes for fixation

is

A

set

therefore not excessive.

FIXING BATH TROUBLES A. Sludging of the Fixing Bath.

—A

The

milkiness

ing,

it

b.

in use for

turn milky some time.

of two kinds

pale yellow and settles very slowly on stand-

is

and may be caused by:

consists of sulphur

Too much acid in the hardener. Too little sulphite or the use of impure

a.

is

may be

If the precipitate

1.

may

bath

fixing

immediately on adding the hardener or after being

sulphite, in

which case there

not sufficient present to protect the hypo from the acid.

High temperature. The hardener should only be added to the hypo when at room temperature. If the temperature of the acid fix-

c.

solution

ing bath

is

many

over 85°F. (29°C.),

longer than a few days even

fixing baths will not

when mixed

bath (Formula F-5) given previously 85°F. (2g°C.) due phurizes, the only If a sulphurized

gelatin,

and

later

to its

bath

keep two or three weeks at

high sulphite concentration.

remedy

may

will

is

is

throw

to

used,

it

remain clear

The potassium alum

correctly.

When

away and mix

some sulphur

is

a bath sul-

a fresh solution.

apt to be retained by the

cause fading of the image as a result of the forma-

tion of silver sulphide. If the precipitate is

2.

hours,

consists of basic

it

white and settles out on standing for a few

aluminum

sulphite.'-®

This sludge

may

be

caused by:

Too

a.

calls for less

little

acid in the hardener.

pure glacial acetic acid and

For example, supposing a formula

28%

acid

is

used by mistake, then

than one-third the required amount has been added.

b.

Too

28

S. E.

little

hardener in the fixing bath.

Sheppard and A. Ballard,

/.

When

fixing prints, a rela-

Frank. Inst. 200, 537 (1925)-


MIXING AND USING PHOTOGRAPHIC SOLUTIONS tively large proportion of the developer

is

165

carried over to the fixing bath

which soon neutralizes the acid and, therefore, increases the tendency for precipitation of aluminum sulphite. In the same way, a fixing bath with the correct proportion of hardener, when exhausted,

alum and sulphite but no aluminum sulphite. It is

to

is

and these combine

to

still

contains

form a sludge of

extremely important, therefore, to use only the acid specified and

know

acid

acid,

its

strength, because trouble

used than

is

is

caused

called for in the formula.

It

either

if

more or

less

has been found that the

hardening properties of a potassium alum acid fixing bath bear a

rela-

aluminum sulphite. In other words, a bath containing an excess of acid, and which, therefore, may be used for a relatively long time before the aluminum sulphite precipitates, does not harden as well as a bath which precipitates when a much smaller quantity of developer is added. With such a bath containing a minimum concentration of acid, it is advisable to add a furtion to the tendency of the bath to precipitate

ther quantity of acid as soon as a slight precipitate appears or preferably

when

the acidity begins to

measured by a chemical

as

fall off

test,-''

a

satisfactory quantity being about one-half that originally present in the

A

bath.

bath can usually be revived two or three times

before the fixing power of the

The

hypo

is

in this

way

exhausted.

addition of boric acid to a fixing bath containing potassium alum

which normally requires several revivals with acetic acid during its useful life to prevent sludge formation will greatly minimize this difficulty

and

also extend the hardening life of the bath."*'

With

the potassium

alum stock solution hardener formula given prealuminum sulphite

viously (page 157) the precipitation of a sludge of

may

also be prevented

by the addition

of 25

grams of sodium potassium

tartrate (Rochelle salts) per liter (375 grains per quart) of the solution.

^Mineral acids, such as sulphuric, are generally too strong for use with fixing solutions except with baths containing

sulphuric acid

is

to be preferred.

chrome alum,

Other organic acids than

for

which

acetic,

such

as citric, tartaric, etc., can only be used under certain very limited conditions, since they tend to interfere with hardening.

B.

The Bath Does Not Harden

hardening

may

be a result of

i.

Satisfactorily.

not contain the correct proportion of aluminum or 29 "

Some

Properties of

â&#x20AC;&#x201D;

Insufficient

alum which does chromium sulphate.

the use of inferior

Chrome Alum Stop Baths and Fixing Baths

â&#x20AC;&#x201D; Part

II

"

by J. I. Crabtree and H. D. Russell. /. Soc. Mot. Pict. Eng. 14, 667 (June 1930).. 30 " An Improved Potassium Alum Fixing Bath Containing Boric Acid " by H. D. Russell and J. I. Crabtree. /. Soc. Mot. Pict. Eng. 21, 137 (August 1933)-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

166

2.

The presence

On

of alum.

much

of too

acid or sulphite or an insufficient quantity

varying the proportions of acid, alum, and sulphite in a

potassium alum fixing bath,

it

has been found that the hardening

creases as the quantity of potassium

alum

increases.

With

in-

increasing

quantities of acetic acid with a given quantity of potassium alum, the

maximum beyond which the hardening deminimum quantity of acetic acid, however, is neces-

hardening increases to a creases.

A

certain

sary to give the fixing bath a fairly long, useful sulphite precipitates, but this quantity tity

which produces

maximum

life

With

hardening.

maximum

87 °C.) beyond which the hardening

The hardening boric acid

is

aluminum

use, therefore, the hard-

ening ability of most potassium alum fixing baths at the addition of developer to a

before

usually greater than the quan-

is

first

increases with

(170° to i90°F.)

(76° to

falls off rapidly.

potassium alum acid fixing baths containing

life of

from three to four times greater than the same type of bath

A

without boric acid.

fixing bath containing boric acid also does not

sludge until the bath has become quite alkaline sible, therefore, to

(pH

= 7.0).

It

is

pos-

use baths containing boric acid equally as long or

longer than the older type of potassium

alum

fixing baths,

and without

the necessity of revival.

Fixing baths containing chrome alum usually have high

properties rapidly either tion of

chrome alum,

many

2%

or over, the hardening properties are mainlife is

life.

With a

fixed proportion of

decreased.

An

in-

and increases the chrome alum and sul-

crease in the sulphite content lowers the hardening

sulphurization

hard-

of

tained better on storage but the sulphurization

phite, the hardening

initial

them lose their hardening with or without use. With a high cencentra-

ening (over 2i2°F.) (ioo°C.) but

life

produced with alkaline film increases with the acid

concentration within certain limits.

C. Blisters.

— When a

film or print

is

transferred directly

and with-

out agitation from a developer containing a fairly high concentration of

an alkaline carbonate

to a strongly acid rinse or stop bath, or to

a

strongly acid fixing bath, small bubbles of carbon dioxide gas are apt to

form within the gelatin the carbonate.

film layer as a result of the action of the acid

If the gelatin film

a small pocket of this gas gelatin film blisters

and leaves a

is

created which bursts through the tender

spot, called a blister.

On

dry film or prints

appear as tiny crater-like depressions when examined by

flected light

(Fig. 75).

weather, and especially

This trouble

when

on

has become softened for any reason,

is

more

re-

likely to occur in hot

the rinse bath or fixing bath

is

not hard-


.

MIXING AND USING PHOTOGRAPHIC SOLUTIONS ening sufficiently.

and

is

maintained

If the gelatin is

not allowed to swell,

it

167

hardened condition

in a

can withstand the disruptive force of

the gas.

Concentrated developers containing a high percentage of carbonate

have a greater tendency carbonate concentration. in

to

produce

blisters

than developers having low

obvious that prolonged development

It is also

to become swollen exceswarmer than 70° F. (2i°C.).

an exhausted developer allows the gelatin

sively, especially

if

Fig. 75

the developer solution

Blisters

is

on a film emulsion (enlarged greatly)

by observing

Blisters can be prevented entirely

the following precau-

tions: a.

Keep

the

temperature of

working solutions around 65 °F,

all

(i8°C.) for films or plates, and around 70°F. (2i°C.) for papers. b.

Agitate the films or prints

when

first

immersed

in the acid rinse or

fixing bath. c.

Whenever

possible, use a cool water rinse previous to or instead of

the acid rinse bath. d.

Use a non-blistering

alkali

in

the developer such as borax or

Kodalk. If the

wash water temperature

low)

it is

ture

and a chrome alum

ough

is

below 65°F. (i8°C.) (but not too

usually possible to maintain the solutions around this tempera-

rinse

is

rinse bath

can be eliminated, provided a thor-

given in running water previous to immersion in an acid

hardening fixing bath.

If

the

ever, 75°F. (24°C.) or above,

wash water temperature

and the temperature

is

high,

how-

of the processing so-


168

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

lutions can be maintained at 65°F. (i8°C.), a rinse should be used to avoid possible trouble

chrome alum hardener

from

blisters.

When

the

temperature of the processing solutions cannot be held around 65 °F. (i8°C.) and

if it

sodium sulphate

75°F. (24°C.) or above,

rises to

to the developer

Chapter VIII.

and hardener

it is

necessary to add

rinse as discussed in

D. Dichroic Fog. If the fixing bath does not contain acid or if old and exhausted and contains an excess of dissolved silver salts,

it is

a stain called dichroic fog

sometimes produced on the

is

flected light, film stained in this

mitted light

it

fresh acid fixing bath or

ject of dichroic fog

Scum on

is is

the film

if

is

by

In retrans-

Dichroic fog never occurs in a rinsed before fixing

and the tem-

kept at 65° to 7o°F. (18° to 2i°C.).

The sub-

discussed fully under Chapter XI, page 249.

the Surface of Fixing Baths.

exhausted fixing bath

film.

looks yellowish-green and

appears reddish-pink.

perature of the bath

E.

way

— When a

hydrogen sulphide gas usually present

in the air reacts

with the silver

thiosulphate in the bath and forms a metallic appearing surface of the solution.

partially

allowed to stand several days without use, the

is

scum on the

This scum consists of silver sulphide and should

be removed by drawing the edge of a sheet of blotting paper across the surface of the bath, or

by using a skimmer made

of several strips of

cheesecloth stretched over a wire frame (Fig. 20, page 40).

A white

scum

consisting of

the films or prints.

velopment;

2.

This

is

aluminum

caused by:

i.

is

found sometimes on

insufficient rinsing after de-

too low a concentration of acid in the fixing bath; 3. in-

sufficient agitation of the film

Since

sulphite

aluminum

sulphite

is

on

first

immersing

soluble in alkali the

in the fixing bath.

scum may be removed

by swabbing the film or print with a 10% solution of sodium carbonate and then washing thoroughly. When using a chrome alum hardener rinse or fixing bath containing chrome alum, a greenish white scum consisting of chromium hydroxide

chromium sulphite is sometimes precipitated on the surface of when an excess of alkaline developer is added to the solution containing the chrome alum. The precipitate may also form on the film locally if it is not agitated sufficiently when first immersed in the hardener or fixing bath. It is readily removed from the wet film by swabbing with moist absorbent cotton but it is very difficult to remove when or basic

the film

once dried on the film surface.

sium

citrate

is

effective

Treatment with a

sometimes

in

5%

solution of potas-

removing the dried scum deposit


MIXING AND USING PHOTOGRAPHIC SOLUTIONS but care must be used since Rinsing

quickly.

in

treatment softens the emulsion very

this

water previous to immersion

when

or fixing bath and thorough agitation

first

in the

XI

film in

scum

Chap-

(see

for further details).

— When processing

F. Mottle.

image

hardener rinse

immersing the

either bath will usually prevent the formation of the ter

169

is

when

occasionally found

tated enough on ficiently rinsed

first

immersing

films or plates in hangers, a mottled

the hanger or rack has not been agi-

in the fixing

between development and

bath or

fixation.

if

the film

insuf-

is

In the absence of

thorough rinsing and agitation, development continues locally during the few minutes of

first

density.

and

fixing,

INIottle is also

in these spots the

produced

image has greater

the ends of the hanger protrude

if

above the surface of the fixing bath especially during the

first

stages of

fixation.

A roll

is

encountered when processing

films which have a dye-coated backing

for reducing halation effects.

mottled pattern of color sometimes

This coating

is

normally removed during processing, but

come off if the solutions do not have as when two films adhere back to back.

free access to the

5%

the film in a

It is easily

it

does not

removed by bathing

by re-immersing

solution of sodium sulphite or

all

back of the film in the

developer for a few minutes and tlien washing thoroughly.

G. Stains.

num

— Several

different types of stains such as white alumi-

sulphite stain (see E. above), sulphur stains, and yellow silver

For a complete discussion of stains

stains are occasionally produced.

caused by fixing baths, reference should be made to Chapter XI, page 230.

MISCELLANEOUS SOLUTIONS The number

of miscellaneous solutions used in

ening, intensifying, reducing, toning, etc.,

is

photography

so large that

it

for hardis

beyond

the scope of this book to deal with other than outstanding cases.

procedure

is

in general

much

the

same

ing baths, and the order of mixing

is

as

when mixing developers

The or fix-

usually stated very specifically.

This solution is recA. Superhardener for Bromide Papers. ommended for use after fixation and washing previous to drying on a heated belt dryer, in order to overcome the tendency of glossy prints to stick

on the

belt.

It

be sepia toned because tone.

should not be used it

if

the prints are later to

sometimes has a detrimental

effect

on the


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

170

Supplementary Hardener

[SH-2] Solution

Water Sodium Sulphite, desiccated. *Acetic Acid, 28% pure

F.) (71° C.)

to *

ounces

4^2 drams 4Jo ounces

18.0 135.0

ounces

2.0

16 1

ounces ounce

500.0 30.0

64

ounces

2.0

liter

grams cc cc

grams liters

cc

grams

add cold water

make

To make 28%

fluid

64

.

Borax

dissolved,

1.0

45.0 64.0

2

Potassium Alum Water to make Solution B Hot water (about 160°

ounces

IM ounces

32 ...

or Glacial Acetic Acid, pure cone.

When

Metric

Avoirdupois

A

acetic acid

from

liters

glacial acetic, take 3 parts of glacial acid

and add

8 parts of water.

Solution

A

should be dissolved in the same

the acid hardener given on page 157.

Then

way

as

recommended

water as recommended and add cold water to make up to volume. cool borax solution should then be

for

dissolve the borax in hot

added slowly

The

to the cool Solution

A

while stirring the latter rapidly.

If these directions are followed, a clear

solution will be obtained, but

the

if

warm borax

solution

is

added too

rapidly to Solution A, a white precipitate will form which does not re-dissolve.

Prints should be fixed in the regular fixing bath,

and placed

in the

hardener for

5 or

10 minutes.

washed thoroughly,

Then wash thoroughly

and remove surplus water before drying. Ammonium persulphate is the B. The Persulphate Reducer. only photographic reducing substance known which acts very much more on the heavy deposits than on the light deposits of the negative. It must

be used in acid solution as given in the following formula, and is somewhat uncertain in its behavior, occasionally refusing to act, and always acting more rapidly as the reduction progresses. This type of reducer is known as a super-proportional reducer and is described in a comprehensive paper on the subject of reducers and intensifiers by Crabtree and Muehler.^i

Persulphate Reducer

[R-l]

Water

Ammonium

Persulphate

Stock Solution Avoirdupois ounces 32 ounces 2

Sulphuric Acid, C. P. (concentrated)

For

use, take

When

i

%

dram

Metric 1.0 liter

60.0

grams

3.0 cc

part of stock solution and add 2 parts of water.

reduction

is

complete, immerse in an acid fixing bath for a few minutes,

then wash. " Reducing and Intensifying Solutions for Motion Picture Film and L. E. Muehler. /. Soc. Mot. Pict. Eng. 17, looi (1931).

31

tree

"

by

J. I.

Crab-


MIXING AND USING PHOTOGRAPHIC SOLUTIONS According to is

due largely

S.

E. Sheppard

the capricious behavior of persulphate

In preparing this solu-

to variations in the iron content.

tion, therefore, only tested

C.

â&#x20AC;˘'-

171

samples of persulphate should be used.

The Permanganate Reducer,

reducer, a typical formula of which

is

â&#x20AC;&#x201D; In

mixing the permanganate

given below,

is

it

sometimes

diffi-

cult to get all the salt to dissolve, for although fairly soluble the crystals

are quite hard and therefore dissolve slowly, especially in cold water.

The

method

best

is

to dissolve the crystals in

very hot water (about

i8o"F.) (82 °C.) with shaking and then dilute with cold water.

A

mixing procedure should be used when preparing

slightly different

large volumes (several

manganate base

is

hundred gallons) of

level

Add

this reducer.

crystals to a small shallow tank or

the per-

box supported so that

with the top of the large storage tank.

its

the small tank

Fill

with water and arrange an open outlet at a point near the top of the tank.

A

small stream of water should be arranged to run into the small

tank at a rate

sufficient to

keep the tank

full.

The

inflow

must not be

up the crystals and cause them to float. After all the crystals have been dissolved, add sufficient water to the large tank to bring the solution up to 90% of the total volume. Then add the sulphuric acid slowly while stirring the large volume of permanganate solution. This method of mixing has the advantage that it insures comso great as to stir

plete solution of all the

permanganate before the solution

is

A

used.

lead-lined iron tank or preferably an iron tank lined with acid proof

brick represents a suitable construction material for holding acid per-

manganate.

Permanganate Reducer

[R-2]

Stock Solution Avoirdupois ounces 32 A. Water Potassium Permanganate IH ounces B.

Cold water Sulphuric Acid, C. P. (concen-

32

trated)

1

Metric 1.0 liter

52.5

ounces fluid

1

ounce

grams

.0 liter

32.0 cc

For use, take i part A, 2 parts B, and 64 parts of water. When the negative has become reduced sufficiently, immerse in a plain hypo solution, or in a fresh acid fixing bath for a

few minutes,

In addition to

employed as a

its

to

remove yellow

stain, after

which wash thoroughly.

use for reduction and bleaching, permanganate

test for

hypo, since

it is

at once reduced

colored solution of the permanganate, therefore, loses 32 "

The

Effect of the Iron Content of

graphic Reducing Brit. J. Phot. 6s,

Power" by 314 (191 8).

S. E.

Ammonium

Sheppard.

is

by hypo, and the its

color in the

Persulphate on

Its

Photo-

Phot. J. Amcr. 55, 29" (1918)

;

also


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

172

presence of any hypo.

It

may

test the extent

consequently be used to

hypo from negatives or prints in washing (see Formula HT-ia, page 313). When permanganate is reduced, a brownish precipitate of manganese dioxide is obtained and sometimes negatives or prints which have been treated with permanganate are stained brown by Fortunately, manganese dioxide is removed by sodium this material. bisulphite which reduces it still further, forming a soluble manganese The brown stain can, therefore, be removed by immersion of the salt.

of the elimination of

stained material in a

5%

solution of bisulphite.

D. Farmer's Reducer. sists of a

â&#x20AC;&#x201D; This subtractive

or cutting reducer con-

mixture of potassium ferricyanide and hypo.

composes very rapidly as soon as the ferricyanide For

this reason, the

is

The

solution de-

added

to the

hypo.

reducer components should never be added together

until just before using.

prepared by mixing a strong solution and adding the required volume (accord-

It is best

of ferricyanide (about 20^'^

),

ing to the strength desired) to a lo^c solution of plain hypo.

Details have been worked out

by A. ^Murray

for using

Farmer's

re-

ducer in a controlled manner for the peripheral reduction of half-tone dots on photographic negatives to be used for lithographic work.^'^

Crabtree and iMuehler

-^^

have published directions

for the

use of

Farmer's reducer in two solutions as well as for the usual single soluThe material is treated first in the ferricyanide and then in the tion. This method has the advantage that the potassium

h)T)o solution.

ricyanide solution will keep indefinitely provided strong daylight.

E. Ferric

it

fer-

shielded from

is

(See Formula R-4b, page 322.)

Alum

Proportional Reducer.

â&#x20AC;&#x201D; The only known pro-

portional reducer which will keep satisfactorily consists of an acid solution of ferric alum, the formula for

Ferric

[R-7]

Alum

which

is

as follows:

Proportional Reducer Avoirdupois

Water Sulphuric Acid, C. P. (concentrated) Ferric Ammonium Sulphate (Ferric

ounces 16 2J^ fluid drams

Ammonium Alum)

Water

to

make

Vi

32

ounce ounces

Metric 500.0 cc 10.0 cc 15.0 1 .0

grams liter

be careful to add the acid to the water solution and not vice versa or the water will boil with explosive violence (see Section J on Sulphuric Acid, page 175). The negative should be hardened with

When mixing,

33 "

New

Control Methods in Chemical Retouching " by A. Murray.

77, 121 (1930). 34 " Reducing

tree

and Intensifying Solutions for Motion Picture Film and L. E. Muehler. /. Soc. Mot. Pict. Eng. 17, looi (1931).

"

Brit. J. Phot.

by

J. I.

Crab-


MIXING AND USING PHOTOGRAPHIC SOLUTIONS

173

an alkaline solution of formalin before treatment as the reducer has a strong tendency to soften the gelatin (see Formula SH-i, page 314).

Important.

â&#x20AC;&#x201D;

It is

very important when using this reducer to keep

the film thoroughly immersed while in contact

eral

remains in the solution.

it

brown

stain will also form

if

the negative contains traces of

or silver salts.

The Iodine-Cyanide Reducer.

F.

ducer

made from

is

during reduction.

Iodine

tion of potassium iodide,

is

â&#x20AC;&#x201D; A very powerful cutting

i

re-

and

to

make up

is

the reducer,

10%

formed

soluble in a solu-

parts of iodine

5

solution of potassium iodide.

part of sodium or potassium cyanide in 10 parts of the

iodine-iodide solution

The

silver iodide

not soluble in water but

crystals are dissolved in 100 parts of a

dissolve

Genhypo

a solution of iodine in potassium iodide, to which

potassium cyanide has been added to dissolve the

Then

If left

with the air for any appreciable time, stains will result.

and make up

activity of the reducer

may

100 parts with water for use.

to

be decreased by diluting with water.

This reducer can be used effectively for bleaching out the silver image after inking over certain parts of a print or

has the advantage that

When

it

bromide enlargement.

using the reducer, the usual precautions should be observed

relative to the use of the poisonous chemical,

page 271).

G.

It

does not leave any residual stain.

The Monckhoven

potassium cyanide (see

â&#x20AC;&#x201D; Solution B

Intensifier.

Monckhoven's

of

intensifier (formula given below), containing silver nitrate and potassium cyanide, often proves a stumbling block when mixed the first few

times.

secret of mixing this solution correctly consists in having

The

excess of silver present, which

is

to the cyanide solution so that a

on standing. If there is

Then

filter off

assured

by adding enough

permanent precipitate

is

an

silver nitrate

obtained even

the precipitate before using the solution.

not an excess of silver present, after bleaching in the Solu-

tion A, the

image

will

be dissolved by the cyanide.

Mercury

Intensifier

[Ii^-l] Metric

Avoirdupois 24

Vl'ater

Potassium Bromide Mercuric Chloride Water to make

Bleach the negative

in the

J^

%

32

ounces ounce ounce ounces

above solution until

750.0 cc 22.5 grams 22.o ftrams 1.0 liter

it is

white, then

wash

thoroughly.

The

negative can be blackened with lo^o sulphite solution or a de-

veloper such as

Formula D-72 diluted

1:3, or with

10% ammonia


174

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

(cone.

28% ammonia

diluted 1:9), these giving progressively greater

To

density in the order given.

increase contrast greatly without in-

shadow portions blacken

creasing the density in the

in:

A

Solution

Avoirdupois

Water

16

Sodium

or Potassium Cyanide ....

}4,

500.0 cc

ounces ounce

500.0 cc 22.5 grams

16

Silver Nitrate, crystals

M

* The usual precautions regarding the use of cyanide which should be observed (see Chapter XIII, page 271).

To prepare

the intensifier, add the silver nitrate Solution

A

cyanide Solution

until a

to stand a short time

and

permanent precipitate

filter.

H. Silver Intensifier. that

it

This

is

a deadly poison

is

B

the potassium

to

just produced; allow the

is

mixture

called Monckliovcn's intensifier.

â&#x20AC;&#x201D; The following formula has the advantage

image of neutral

yields an

grams

15.0

B

Solution Water

Metric

ounces ounce

color,

whereas most

intensifiers

change

the original color of the image giving an image which varies in hue from

a bluish-black to a reddish-brown or yellow."'^

motion picture projection prints, lantern

The

a very useful formula.

and the degree of

resulting

the standpoint of

solution gives proportional intensification

intensification

The

of treatment.

From

slides, or transparencies, it is

is

by varying the time

easily controlled

image

is

permanent.

Silver Intensifier

[In-5]

(Store in a

Stock Solution No.

brown

bottle)

Silver Nitrate Water to make

Stock Solution No.

Sodium Water

2

32

ounces ounces

60.0

ounces ounces

60.0

ounces ounces

105.0

grams

1.0 liter

2

Sulphite, desiccated

2

make

to

Metric

Avoirdupois

1

32

grams

1.0 liter

Stock Solution No. 3

Sodium

Tiiiosulpliate (Hypo) (crys-

tals)

33^2

Water

make

to

32

grams

1.0 liter

Stock Solution No. 4

Sodium

Sulphite, desiccated

J4

Elon

Water

Directions to

I

to

for

Mixing.

part of Solution No.

mixing.

The white

addition of

i

345 96

make

â&#x20AC;&#x201D; Slowly i,

i

grains

ounces

part

of

Solution

precipitate which appears

part of Solution No. 3.

2

is

then dissolved by the

Allow the resulting solution to

Then add, with

stirring, 3 parts of

" Reducing and Intensifying Solutions for Motion Picture Film and L. E. Muehler. /. Soc. Mot. Pict. Eng. 17, looi (1931).

35

No.

shaking or stirring to obtain thorough

stand a few minutes until clear.

tree

add

15.0 grams 24.0 grams 3.0 liters

ounce

"

by

J. I.

Crab-


MIXING AND USING PHOTOGRAPHIC SOLUTIONS The

Solution No. 4.

intensifier

is

now ready

175

and the negative

for use

(or transparency) should be treated immediately.

The degree of intensification depends upon the time of treatment which should not exceed 25 minutes; normal intensification should be obtained usually in 10 to 20 minutes. Then immerse the negative for 2

minutes

The

in a plain

solution

is

30% hypo

and wash thoroughly.

solution

stable for about 30 to 45 minutes before a precipitate

of silver forms in the bath.

If

used after this time limit, a precipitate

appears which will deposit on the highlights and produce fog.

The Caustic

I.

Alkalis.

— When

dissolving

either

sodium hy-

droxide (caustic soda), or potassium hydroxide (caustic potash), never use hot wafer because the heat of solution evolved solution

and

stir

is

apt to boil with explosive violence.

frequently to prevent local heating of the solution.

of these solutions

is

heavy caustic solution

Sulphuric Acid. acid or when adding the J.

is

— When

bottom on account

making

higher

its

dilute solutions of sulphuric

In the latter case, excessive heat

may

meets the acid and the acid

Hypo-Alum Toning

Baths.

add

the water to

produced when the water

— Occasionally when a hypo-alum

mixed, the solution turns a

The

formation of silver sulphide.

is

and never

spatter on the hands or face causing

serious burns.

is

of

acid to a developer or a fixing bath, always

the concentrated acid to the water with stirring

toning bath

either

stirred thoroughly, otherwise the

will sink to the

specific gravity.

the acid.

When

added as a component part of another solution,

care should be taken that the bath

K.

so great that the

is

Always use cold water

murky black

as a result of the

usual hypo-alum bath consists of a

mixture of hypo and potassium alum, with or without the addition of silver chloride or silver iodide.

toning bath given below or

hypo-alum bath cipitate, the

is

bath

not stirred will

If boiling

water

is

the order of mixing

if

when adding

used for mixing the is

changed or

if

the

the white silver chloride pre-

turn a dirty gray or black.

Once the

solution

cannot be cleared immediately except by a tedious filtration process, but it will settle out almost completely if allowed to stand overnight when the clear supernatant liquid may be poured or

becomes black,

siphoned

it

off for use.

Hypo- Alum Bath

for Sepia

Toning

Avoirdupois

Cold water

90 ounces

Hypo

It

ounces

(Formula continued on next page)

Metric 2800.0 cc 480.0 f^rams

[T-la]


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

176

Dissolve thoroughly, and add the following solution: Hot water (about Potassium Alum

Then add

160° F.) (71° C.)

20

ounces

640.0 cc 120.0 grams

4 ounces

the following solution (including precipitate) slowly to the

h)^o-alum solution while

stirring the latter rapidly.

Cold water

2

ounces

60 grains 60 grains

Silver Nitrate Crystals Sodium Chloride (table salt)

64.0 cc 4.2 grams 4.2 grams

After combining above solutions

Add water Note

The

to

make

1

gallon

4.0 liters

adding the sodium and immediately afterward the solution containing the milky white precipishould be added to the hypo-alum solution as directed above. :

silver nitrate should be dissolved completely before

chloride, tate

For

pour into a tray standing

use,

(49°C.).

water bath and heat to i20°F.

in a

Prints will tone in 12 to 15 minutes.

The bath should never be heated above i25°F. (52°C.), otherwise blistering, staining,

and non-uniform toning

Toning Bath.

L. Sulphide

— When

will result.

by the redevelopment process, a solution of sodium sulphide is used for redeveloping. Sodium sulphide is supplied commercially in two forms, crystalline and fused sulphide. The latter is to be preferred for photographic work, sepia toning

since the crystalline form deliquesces or absorbs moisture from the air

very quickly and

is

The crystals often contain One part by weight of fused (approximately) by weight of the

troublesome to handle.

impurities and do not yield a clear solution.

sulphide

equivalent to three parts

is

Both

crystals.

varieties contain iron as

an impurity.

In preparing a

sulphide solution, the chemical should be dissolved in hot water and

allowed to stand about 24 hours before use.

The

iron sulphide settles

out as a sludge and the clear yellow solution should be decanted off before use.

Sodium sulphide

crystals

sometimes contain hypo as an

impurity, which will attack the highlights of the print and give a

bleached out effect in the

final tone.

Toning baths containing sulphide

should not be used near developer solutions or fog will result.

M. Iron Toning Bath, tive

—-Lantern

motion picture film are often toned

and posiby treatment in

slides, transparencies,

to a blue color

a bath containing iron (ferric) ferricyanide, the silver image being partly

converted to a mixture of silver ferrocyanide and ferric ferrocyanide by the process.

Unless instructions are followed carefully when preparing

the toning bath, a certain degradation of tone will result.

formula

is

as follows:

A

typical


MIXING AND USING PHOTOGRAPHIC SOLUTIONS Iron Toning Bath

[T-11] Avoirdupois

Ammonium Persulphate Ferric Ammonium Sulphate (Ferric Alum)

7 20

Oxalic Acid

45

Potassium Ferricyanide

15

Ammonium Alum

75

Hydrochloric Acid, 10% Water to make

32

Dissolve chemicals *

A 10%

solution of hydrochloric acid

trated hydrochloric acid and adding

Directions for Mixing.

it

in is

grains grains grains grains grains

Metric 0.5 ftram 1.4 3.0 1.0 5.0

^ dram

grams grams gram grams

1.0 cc 1.0 liter

ounces

order given.

prepared by taking

i

part of concen-

to g parts of water.

— Dissolve each

of the solid chemicals sepa-

(preferably in a glass or enamelled ware container, free of

rately

cracks) in a small volume of water, and

The

177

filter

into the tank or crock.

solutions should be mixed strictly in the order given,

luted to volume with cool water.

and then

di-

If these instructions are followed, the

bath will be pale yellow in color and perfectly clear.

When

preparing a uranium toning bath, or a uranium mordanting

bath, similar precautions should be followed (see page 327).

N.

Dye

tern slides

Solutions,

— Dyes

and motion picture

the mixing vessels should be

are used for tinting and toning of lan-

films.

made

When

preparing solutions of dyes,

of hard glazed earthenware, stone-

If enamelled ware is used, it should have a high glaze any cracks which would expose the metal underneath and tend to contaminate the dye solutions. The solid dye should be dissolved in as small a volume of hot distilled water as possible, and filtered

ware, or glassware.

and be

free of

through fine muslin or a suitable mechanical

that

all

be diluted to the required

volume with cool

distilled

Chapter

(see

filter

Hot water should be poured over any the dye will be dissolved. The solution in

page 32).

III,

residue remaining so the tank should then

water (about 65°F.)

(i8°C.).

Very

dilute solutions of certain dyes are also used for optical sensitiz-

ing of films or plates

by bathing.

Dundon

has described the special

technique involved for such work and reference should be original paper for

working

details."'

Dyes

made

to the

are also used in a preliminary

bath before development or added to the developer to desensitize the emulsion and permit development in brighter

The technique

light.

for

mixing desensitizers has been described on page 144. 36 " Color

Amer. Phot.

Sensitizing

Photographic

20, 670 (1926).

Plates

by

Bathing

"

by

M.

L.

Dundon.


CHAPTER

VIII

HANDLING SOLUTIONS AT HIGH TEMPERATURES Photographic solutions give the most satisfactory and uniform results

when used

normal temperatures of 65°F. (i8°C.)

at the

materials and 70° F. (2i°C.) for positive materials.

degrees above or below these temperatures sions arise

except by

when

it

extremely

is

difficult

not significant but occa-

is

control the temperature

to

artificial refrigeration or heating.

for negative

Variation of a few

Several methods of tem-

perature control have been discussed under Chapter V.

When

a gelatin film

is

placed in an alkaline developer solution,

ally starts to swell immediately.

high, 75° to 90° F.

and becomes very is

usuis

(24° to 32 -C), the gelatin swells more rapidly soft

and

difficult

ers containing carbonate, the

tion

it

temperature of the developer

If the

increased greatly

when

the film

blister

formation and reticula-

placed subsequently in the acid

is

The developer

rinse or in the acid fixing bath.

Also, with develop-

to handle.

danger of

solution,

on the other

hand, oxidizes more rapidly and tends to fog and stain at a much earlier stage of exhaustion than at normal temperatures.

The

extent of these swelling and shrinking effects mentioned above

has been measured by Sheppard

and the

^

results of a typical case with

motion picture positive film at normal temperatures are shown ure 76.

At higher temperatures

or

when

the temperature

is

in Fig-

different for

the various operations, the expansion and contraction effects are

worse.

In

fact, the strains set

up

may

much

be so great as to distort the gela-

produce reticulation (see Fig. 77). It is important, maintain all photographic solutions at a temperature as

tin sufficiently to

therefore, to

nearly normal as possible (65° to 70° F.)

(18° to 2i°C.), but

if

this

cannot be done, the various solutions should be maintained at equal temperatures.

At high temperatures, the useful shortened because the tendency

life

of

an acid

is

bath

is

usually

increased.

Films

fixing

for sulphurization

which are swollen by processing at high temperatures also require longer to

dry and are more subject to drying troubles than films on which the

gelatin coating

Nearly

all

is

not excessively swollen.

solid chemicals

used

enough melting point so that there

in

photographic work have a high

is little

danger of the solids melting

while stored in bottles or other containers, but

it is

good practice to keep

1 " Behavior of Gelatin in the Processing of Motion Picture Fihn Sheppard. Trans. Soc. Mot. Pict. Bug. No. 32, 707-727 (1927).

"

by S. E.


.

SOLUTIONS AT HIGH TEMPERATURES chemicals as dry and cool as possible during storage. for instance,

17Q

Bottles or cans,

should not be placed on shelves or in cupboards near a

source of heat such as a radiator, an electric light, or a stove, or where direct sunlight can shine

When

in solution

upon them

must be taken Chapter \').

greater and tion (see

(see C'hapter IX, page 195

)

the effect of temperature on chemicals

is

much

into account with every photographic solu-

50

^ 40 30 20

10

ALKAUNE

ACID FIXING BATH

DCVeLOPE.R 5 MIN

S MIN

Swelling of Eastman motion picture positive film during processing

Fig. 76

65°F. (i8°C.)

at

The is

secret of processing films or plates under hot weather conditions

to prevent

and some

abnormal swelling of the gelatin coating. Most papers and plates are hardened during manufacture and no

films

trouble from e.xcessive swelling rials.

]\Iost films

and

is

manufacture and the gelatin layer to 43 °C.)

perature

when

is

will

a strip of the material

raised gradually.

melting point of gelatin films sists of

usually encountered with these mate-

however, are not super-hardened during

plates,

A is

melt around 95° to iio°F. (35° is

placed in water and the tem-

suitable apparatus for determining the

shown

in

Figure 73, page 156, and con-

The wooden frame which is

a beaker of water heated by means of an electric hot plate.

strips of material to

be tested are pinned

to the

immersed in the beaker of water. With unhardened materials, care must be exercised when handling if the temperature of the processing solutions or the wash water is above 75°F. (24°C.). A few materials such as x-ray film and some motion picture films are coated with emulsion on both sides

and require

special precautions

when handling

at


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

180

high temperatures. is

With

roll films

and cut

films, the

back of the film

coated with a layer of gelatin which serves to prevent curling and the

degree of hardness (melting point) of this layer

is

usually greater than

Motion picture films (except double coated do not have a gelatin coating on the side opposite to the

that of the emulsion layer. positive)

emulsion.

Fig. 77

— Reticulation of a gelatin

Special Technique for is

film.

High Temperature Processing.

If

it

impossible to install a cooling system, a special technique must be

adopted in order to process films or plates satisfactorily at temperatures above 75°F. (24°C.). This technique consists in i. using developers containing a high concentration of sodium sulphite and an alkali or an inert salt, such as

and

2.

sodium sulphate,

hardening the film in a

dium sulphate (anhydrous) the unswollen condition.-

An

chrome alum plus 5% soand while the gelatin is in hardened in this manner, it will then

after developing

When

withstand immersion in very ing.

3%

to prevent swelling of the gelatin,

solution of

warm water

without swelling or reticulat-

exception to the technique described above should be

made

with double coated films which are hardened excessively by this procedure. terials at

A

modified technique will be described for handling these ma-

high temperatures.

Development of Films or Plates at Temperatures of 75° to Any good developer may be used which de-

90°F. (24° to 32°C.).

velops fully in 6 to 7 minutes at 75°F. (24°C.).

The developer should

2 " Handling Motion Picture Film at High Temperatures " by Trans. Soc. Mot. Pict. Eng. No. 19, 39-47 (1924).

J.

I.

Crabtree.


SOLUTIONS AT HIGH TEMPERATURES

181

preferably contain developing agents which oxidize slowly, such as Elon, hydroqiiinone, or para-aminophenol and should have a saline content of

not

less

added

An

than io%.

inert salt such as

to the developer to

sodium sulphate should be

supplement the anti-swelling action of the

salts in the developer.

Usually a concentration of lo to

sulphate crystals (4.3 to

6.5% desiccated sulphate)

is

15% sodium

satisfactory.

addition of sodium sulphate retards the development about

30%.

The If

a

developer requires normally about 9 minutes at 8o°F. ( 26. 5°C.), it should be compounded twice as strong so as to diminish the swelling tendency,

when

it

develop in approximately

will

developer at high temperatures

is

dizes rapidly at high temperatures

5

minutes.

The

use of a pyro

not recommended because pyro oxi-

and

Typical

stains the gelatin film.

developers which are satisfactory for high temperature work are given in the

Appendix, page 283.

The Use

of

Sodium Sulphate.

perature control equipment,

70°F. (2i°C.) for temperature

is

all

it is

— In

solutions rather than 65°F. (i8°C.), because this

closest to the average

much and

day emulsions have

The

there

little

is

less

The advantage

room temperature.

of the lower temperature of 65°F. (i8°C.)

not swell as

the absence of precise tem-

better to adopt a basic temperature of

is

that the gelatin film does

tendency to

fog,

although present

propensity to fog when used correctly.

increase in activity of a developer resulting from rise in tempera-

ture can be offset

by adding sodium

When

sulphate.

sulphate has been

added, the developer does not penetrate the gelatin film as rapidly and its

developing activity

is

lowered.

For example, with Formulas correct

gamma

(i.i)

is

DK-50

and DK-60, assuming that the

obtained at 65°F. (i8°C.), the quantities of

desiccated sodium sulphate to add at the various temperatures to

and

DK-60 are given

in the following Table.

If

DK-50

sodium sulphate crystals

are used, double the quantities indicated should be used.

TABLE

6

Total Content of Sodium Sulphate (Desiccated)

DK-60

DK-50 Temperature 70°F.

75°F.

8o°F.

7

2.0% ( 2| 8.5% (12 13.0% (18

Min. oz./gal.) oz./gal.) oz./gal.)

10 Min.

8.5% (12 13.0% (18 16.5% (24

oz./gal.) oz./gal.) oz./gal.)

7 Min.

8.5% 13.0% Not recommended


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

182

Thus, assuming that the developer activity

is

satisfactory at 65 °F.

(i8°C.) withDK-5o,at7o°F. (2i°C.) 8.5% of sodium sulphate should be added and, if the temperature then rises to 75°F. (24°C.), a further

4-5% (13% minus 8.5%) should be added. directly to the tank provided

it is

The

salt

stirred to insure that

may

be added

thoroughly

it is

Similar tables can be prepared for other developers.

dissolved.

Of course, once the sulphate is added, if the temperature drops again, the time of development must be prolonged so that it would appear desirable to maintain the temperature of the developer, if necessary, by means of steam or hot water coils of plain black wrought iron (not galvanized) immersed in the developer tanks.

When

replenishing such developers containing sulphate,

is

it

neces-

sary to add, likewise, an equivalent amount of sulphate to the replenisher.

The

new

introduction of the

Kodalk,

alkali,

in

1934

is

of special

Formula

interest because of its adaptability for tropical development.

DK-15

(page 284) containing Kodalk has been compounded particu-

weather processing and has the following advantages:

larly for hot is

non-blistering because no gas

to the acid

formed when the developer

is

hardener rinse or the acid fixing bath,

2.

i.

It

added the development is

rate changes slowly with time so that on slight overdevelopment, the

negatives will not be too dense, and 3.

tendency veloper

in conjunction

is

hands

minimum scumming The de-

and plates are more conveniently handled

films

when working

in direct contact

The

has a

equally satisfactory for tray or tank use.

Both sheet or racks

it

with the average acid fixing bath.

at high temperatures,

in

hangers

which avoids bringing the

with the materials while wet.

addition of the hardening agent, formalin, directly to a developer

has also been recommended and gives satisfaction in certain cases but in

many

tity of

instances

it

sulphite in the developer.

hyde

For

causes fog.

maximum

hardening, the quan-

formalin must be adjusted carefully to the quantity of alkali and

According to Crabtree and Ross

formalin

is

tion for this reaction

Note on

J.

many

quite objectionable to

in small or poorly ventilated

3

formalde-

reacts with the sulphite constituent of the developer to produce

a formaldehyde-bisulphite complex and sodium hydroxide.

and

^

F. Ross.

"

Use

of

is

The odor

persons and, therefore,

its

of

use

The equa-

darkrooms should be avoided.

as follows:

Formaldehyde

in

Brit. J. Phot. 77, 71, 1930.

Developing Solutions " by

J.

I.

Crabtree


SOLUTIONS AT HIGH TEMPERATURES

183

HCHO + Na,S03 + H.,0 ^ HCHO-NaHSO, + NaOH Sodium

Formalin

Water

Sodium Hydroxide

Formo-Siilpliite

Sulpliite

Although the use of formalin ers,

very limited in single bath develop-

is

presents certain advantages for use with two bath developers for

it

rapid processing, for example, in news photography.'

Bath No.

first in is

in

i

absorbed but very

Bath No.

2

little

development takes place.

film

is

placed

then placed

It is

containing sulphite, formalin, and bromide (plus a de-

Formula SD-6

sensitizer for control of aerial fog), see

Appendix A, page 306. first

The

low alkalinity where a certain volume of solution

of

Development

in Solution 2

in

Chapter XIV,

proceeds rapidly at

but practically stops after a short time when the developing agents

have had time to

diffuse out of the film.

The formalin hardens

the film

and also reacts with the sulphite to form sodium hydroxide which turn activates the developer.

in

Satisfactory results are obtainable at tem-

This method of development avoids the troublesome reactions that otherwise occur between many developing agents and formalin when used in a single bath deperatures from 65° to 85°F. (18° to 29.5°C.).

veloper.

Developer Fog.

If a

developer tends to give excessive fog

when

used at 85°F. (29.5°C.) a small quantity of potassium bromide (30 grains per gallon) (0.5

gram per

liter) or

potassium iodide

dram

(i

of a

lO/r solution of iodide per gallon) (o.oi gram per liter) should be added. If

streaked aerial oxidation fog

produced, add one part in 250,000 of

is

pinakryptol green which will usually eliminate this type of fog (see

method

of mixing desensitizers,

The Rinse over

2

page 144).

— After development,

Bath.

or 3 seconds in water

rinse the material for not

and then immerse

minutes

for at least j

in

chrome alum solution containing s^/c sodium sulphate, anhydrous* (12% crystal sulphate) (Formula SB-4, page 308). Agitate a

3%

the material for 30 or 40 seconds to

when

first

placed in this bath, in order

minimize the tendency for the formation of

chrome alum

stains.

If the film or plate is

tated, the alkali in the developer

mium 4

is

hydroxide on the film which

" Rapid Processing

Methods

30, 67, 142 (1936). * With some negative

" by

blisters, streakiness

apt to precipitate a sludge of chrois

difficult to

H. Parker and

J.

remove.

I.

Crabtree.

materials and providing the temperature

than 85°F. (29.5°C.) the sodium sulphate

and

not rinsed slightly and agi-

may be

Amer. Phot. is

not higher

omitted from the hardener formula.


PHOTOGRAPHIC CHE^HCALS AXD SOLUTIONS

184

The chrome akim

in the

hardener

sufficiently acid to neutralize a

is

considerable quantity of alkali carried over from the developer. addition of acetic acid to the bath

is

not recommended because

creases the tendency for blister formation.

ener rinse bath sometimes

recommended

For

temperatures.

maximum

The

plain

must be maintained between

tion

pH

phuric acid

is

3.8

is

is

and 3.0

for alkaline film.

Sul-

the most satisfactory indicator (see discussion on

Acid should be

by lo-inch films or plates (or per gallon of 3% chrome alum hardener

after processing ten to fifteen 8

their equivalent in other sizes)

The

acid revival

Although

it is

may

usually be repeated several times.

not essential, a rinse of

development and before immersion the

For

value of the chrome alum solu-

preparation and use of an indicator, pages 144-145).

bath.

at high

to be preferred.

the most suitable acid for maintaining the acidity and

brom phenol blue added

which con-

when developing

chrome alum solution

hardening, the acidity or

this reason, the hard-

for photofinishing,

tains acetic acid, should preferably not be used

The

this in-

life of

the chrome

for blister formation.

i

in the

or

2

alum bath and minimize

A

seconds in water after

hardener rinse will prolong still

more the tendency

prolonged water rinse should be avoided, how-

and effective hardmore the gelatin is swollen. Furthermore, the gelatin may be tanned most effectively when it is slightly alkaline and it is, therefore, undesirable to wash all the developer out of the film. Space and time requirements will usually determine whether a water rinse can be used in addition to a hardener rinse. Above 85 °F. (29.5^0.) the water rinse should be omitted if any signs of softening of

ever, as the film continues to swell while in the water

ening becomes more

difficult the

the gelatin are observed.

however, by using a

Softening of the gelatin

10% sodium

may

be avoided,

sulphate solution instead of a water

film for 10 or 15 seconds after

development and

previous to treatment in the chrome alum rinse bath.

This procedure

rinse

and immersing the

remove much of the alkaline developer from the film before it reaches the chrome alum acid rinse bath. When the developer solution is Life of Hardener Rinse Bath.

also

seems

to

â&#x20AC;&#x201D;

carried over in the gelatin layer of the film into the hardening rinse bath,

the

chrome alum solution gradually

loses its hardening properties.

sulphite in the developer reacts with the

chrome alum causing

The it

to

change from a violet-blue colored solution to yellowish-green in which state it ceases to harden. It should then be replaced by a fresh bath.

A

plain

chrome alum solution

definitely,

will retain its

but as soon as sulphite

is

added

hardening properties

to the

in-

bath the solution gradu-


SOLUTIONS AT HIGH TEMPERATURES ally loses its hardening properties

whether used or not, and

185

in the course

of several days will cease to harden gelatin unless the acidity of the bath

has been adjusted as mentioned on page 147. With average use, the hardener rinse bath should be replaced four or five times as often as the fixing bath.

The Fixing in conjunction

Bath.

rinse bath the film should be so

gelatin will not dissolve in boiling water.

the chrome alum bath loses its

is

is

This

may

bath

be used

it

turns green and

Care should be exercised

when

discarded

hardened that the

only true providing

is

not allowed to be used after

hardening properties.

hardener bath

fixing

with the chrome alum hardening bath, because on leav-

chrome alum

ing the

— Any acid hardening

it

loses its

to see that the

hardening powers and

is

replaced by a fresh bath.

Although

is

it

possible to revive fixing baths

when they reach

a cer-

by the addition of a measured quantity of acid, not recommended when working at high temperatures

tain stage of exhaustion this

procedure

is

because of the increased danger of precipitating sulphur.

attempt revival, revival

which

is

is

it

is

safer practice to discard the bath.

Rather than Furthermore,

unnecessary when using the fixing bath containing boric acid

described on page 157.

— After

Washing.

rials for 10 to 15

fixing

minutes.

thoroughly for

If

running water

5

minutes, wash the mateis

not available three suc-

remove most

of the hypo, but a

thorough washing at a later date should be given

in order to insure

cessive soakings of 5 minutes each will

permanency. Warning.

— Films

alum hardener or

or plates which have been treated in a

in a

chrome alum

fixing

chrome

bath should always be wiped

and before drying to remove any possible traces chromium scum which might be on the film surface. Such scum, if

carefully after washing of

is very difficult and often impossible to remove. Processing of Double Coated Films Under Hot Weather

allowed to dry,

Conditions.

— Success

in

high

temperature

processing

of

double

coated films (emulsion coated on both sides) such as x-ray and certain types of motion picture film depends on the observance of the following precautions:

i.

short time of development,

development and

onds after immersion fixing bath,

5.

2.

thorough rinsing between

fixation, 3. agitation of the film for at least 15 secin the fixing bath, 4. use of

a special hardening

limitation of the time of washing to 15 minutes.

Many chrome alum effectively while the

fixing baths are capable of

bath

is

hardening gelatin very

fresh but they lose their hardening proper-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

186

in a

ties

searches

fixing baths

by Crabtree and

have been compounded as a

Russell

A

'

result of re-

which maintain good hardening char-

two weeks unless previously exhausted by

acteristics over a period of

use.

Within recent years,

few days either with or without use.

chrome alum

formula suitable for use with double coated films

is

given in the

Appendix, page 311.

The hardening power of this special chrome alum fixing bath Formula F— 23, page 311) will permit about twenty 8 by lo-inch films or their (

equivalent to be processed per 4

The

processing procedure

is

liters (gallon).

Develop

as follows:

concentrated

in a

developer for times varying from 3 minutes at 7S°F. (24°C.) to 2 minutes at 85 °F. (29.5°C.). Then rinse the films in water for not over 3 seconds or

from 10 to 15 seconds

10% sodium

in a plain

sulphate

bath, immerse in the fixing bath, and agitate for at least 15 seconds.

Fix for at least 15 minutes with occasional agitation.

Wash

for a time

not exceeding 15 minutes in a tank where the hourly flow of water

should be at least twelve times the volume of the tank.

When

hardening

is

the chief consideration, then the chrome alum

fix-

non-scumming properties are also of importance, the special potassium alum acid fixing bath containing Kodalk (Formula F-io, page 311) is recommended. ing bath should be used, but

Although

it is

if

anti-sludging or

possible to handle double coated films at temperatures

above 85°F. (2g.5°C.) by using able to do so

if

this processing technique,

the temperature can be brought

or lower, since the danger of blisters, stains, is

much

down

it is

inadvis-

to 85 ^F. (29.5°C.)

and softening

of the gelatin

greater at higher temperatures.

Relative Temperatures of the Various Solutions.

can-

It

not be emphasized too strongly that high temperature processing should

Whenever

only be regarded as an emergency measure. tions should be handled at

do

so,

then

it is

normal temperatures.

If

possible, solu-

it is

impossible to

important that the temperature of the various solutions

should be maintained as nearly equal as possible.

If a swollen film

subjected to a sudden change of temperature, as, for example, transferring from a cool developer to a

warm

fixing bath, the gelatin

tends to pucker up and assume a leather-like appearance reticulation,

The

which

effect of a

the film

is

it is

not possible to remedy.

sudden temperature change

is

a

is

when

known

as

(See Fig. 77, page 180.)

minimum, however, when

unswollen and hardened.

5 " Some Properties of Chrome Alum Stop Baths and Fixing Baths " by Crabtree and H. D. Russell. /. Soc. Mot. Pict. Eiig. 14, 667 (June 1930).

J.

I.


SOLUTIONS AT HIGH TEMPERATURES The temperature

187

wash water is the governing factor in deterunder any particular conditions. a. If the temperature of the solutions is 90'^F. (32 °C.) and that of the wash water near 65°F. (i8°C.), it is only necessary to cool the tanks with the wash water as described in Chapter V, page 89, and of the

mining the procedure

to follow

use a water rinse between the developer and fixing bath.

temperature after adjustment visable to

add

and

the rinse bath

if

it is

ad-

sulphate crj^stals to the developer.

the solutions are at 90°F. (32 °C.), artificially

If the solution

70° to 75°F. (21° to 24°C.)

temperature of the wash water

If the

b.

10% sodium

is

it is

is

above 75°F. (24°C.), and

necessary to cool the solutions

kept in good condition, the film will

is

be hardened sufficiently to withstand the wash water at temperatures

from

it is

ioo°F. (24° to 38°C.).

75^" to

If the

c.

temperature of the wash water

is

above 75°F. (24°C.), and

not desired to add sodium sulphate to the developer and rinse bath

(assuming that a concentrated developer

above 80' F.) (26.5°C.), then this is an expensive procedure.

it is

is

used at a temperature not

necessary to cool the wash water, but

HOT WEATHER TROUBLES 1.

Fog and Stain During Development.

— Stock developing

so-

As the temperature rises, developers tend to fog photographic emulsions more readily, the solutions oxidize more rapidly, and trouble from stain may be expected. The rate of formation of aerial fog also increases as the temperature rises but this can be retarded by the addition of either pyro or a desen-

lutions should always be stored in a cool place.

Chapter XI, page 249). A pyro developer gives little or even at relatively high temperatures. Most photographic papers are hardened sufficiently in manufacture so that no trouble from softening may be anticipated, but stains and

sitizer

no

(see

aerial fog

fog are likely to be formed on prints controlled carefully.

10%

If the

the developer temperature

if

is

not

developer gives fog, add a few drops of a

solution of potassium bromide to the tray containing 8 ounces of

developer.

It

is

advisable to rinse a few seconds in a

2%

or

3%

acetic

acid stop bath between development and fixation, and to use the regular acid

hardening fixing bath recommended for papers. A more comis given in Chapter XI, page 230.

plete discussion of developer stains 2.

Dichroic Fog.

page 249.

— This trouble

is

discussed fully in Chapter XI,

In reflected light, film stained with dichroic fog looks yel-

lowish-green, and

by transmitted

light,

it

appears reddish-pink.

The


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

188

tendency for the formation of dichroic fog temperature of the bath the fixing bath

by

rises, since

the swollen film.

increased greatly as the

is

more developer is carried over The remedy for dichroic fog is

to to

keep the temperature of the solution down, rinse between development

and

fixation, agitate

thoroughly on

first

immersing the films

ing bath, and renew the fixing bath as soon as 3.

Reticulation.

sively,

is

it

— When

allowed to swell exces-

warm wash

occurs, there

is

may

cause

it

to

Sudden changes

or reticulated (Fig. 77, page 180).

in temperature, such as

removal of the film from a cool fixing bath to

water or vice versa, will produce

this effect.

no way of removing the reticulation.

therefore, to prevent swelling either

by

of all solutions as near 65° to 70°F. b.

is

very sensitive to physical strains, which

become puckered very

a gelatin film

in the fix-

shows signs of aging.

it

a.

It

is

Once

it

important,

maintaining the temperature

(18° to 2i°C.) as possible, or

using a chrome alum hardening bath between development and fixa-

tion, or c.

adding sodium sulphate to the developer and the hardener

rinse bath. 4.

Blisters.

Blisters are

formed

in

carbonate developers usually

during hot weather and as a result of insufficient rinsing. saturated with a carbonate developer

is

When

a film

placed in an acid rinse or fixing

bath, carbon dioxide gas bubbles are released within the gelatin layer of the film.

If this layer

is

not hardened sufficiently to withstand the

disruptive action of the gas, the carbon dioxide crater-like depression

is

left

in the gelatin

rinse thoroughly after developing, to

the use of the

keep

all

is

layer.

released and a tiny

The remedy

is

to

harden the film well (either by

chrome alum hardener or a fresh acid

fixing bath)

solutions as near normal temperature (65° to 7o°F.)

and

to

(18° to

2i°C.) as possible (for further details see page 166 of Chapter VII). Blister formation

may

be avoided entirely, however, by using devel-

opers containing alkalis, such as borax and Kodalk, because neither of

when added to an acid solution. In the case of certain Sulphur Sludge in the Fixing Bath. baths, when adding acid hardener to the hypo solution, it is im-

these substances release a gas 5.

acid

portant that both solutions should be cool (below 85°F.)

(29.5°C.);

otherwise a precipitate of sulphur will form immediately or within a

few hours.

In case the bath precipitates sulphur the only remedy

discard the solution and prepare a fresh one.

Sulphur

will also

is

to

be pre-

if stock solutions of an acid fixing bath are stored for several daysathightemperatures, above 85° F. (29.5°C.). If a fixing bath containing sulphur is used for fixing papers, there is danger of subsequent

cipitated


SOLUTIONS AT HIGH TEMPERATURES

189

fading of the image, resulting from interaction between fine particles of sulphur (held within the pores of the paper) and the silver image,

which

converted to a yellow modification of silver sulphide that

is

The presence

constitutes the faded image.

phur dioxide

of carbon dioxide or of sul-

moist atmosphere accelerates greatly the tendency for

in a

fading.*' 6.

—^A

Green Stain from Chrome Alum Rinse or Fixing Baths. gelatin film

of the stain to

is

usually stained a pale green color after immer-

chrome alum hardener

sion in a

35°C.).

intensity

increased at high temperatures, 80° to 95°F.

It

is

(26.5°

decreased by increasing the sulphite concentration

The

developer and increased by increasing the alkali content.

in the

formation of this stain

the chief reason that

is

baths are unsuitable for use with papers.

formly over the entire

The a.

if

it

is

fixing is

not

distributed uni-

film.

stain can usually be s^'c

chrome alum

Ordinarily, the stain

objectionable from a photographic standpoint

with

The

rinse or fixing bath.

is

removed from

solution of potassium

films or plates

citrate although

by

by treatment

virtue of this treat-

ment the hardening is destroyed. It is desirable, therefore, to harden the film by treatment in an alkaline formaldehyde bath before the stain

A

removal treatment.

suitable hardener formula

is

given on page 314

of the Appendix. 7. is

Scum.

— When a

film saturated with a strongly alkaline developer

placed in a chrome alum rinse or in a fixing bath containing either

chrome alum or potassium alum, there is a tendency to decomposition of the alum with resulting precipitation of a gelatinous sludge which deposits as a scum on the film surface. This tendency is greatest providing the acidity of the rinse or fixing bath is low and the film is not agitated

when

first

immersed

in either bath.

temperature of the processing solutions to flocculate

more readily

is

It is also increased

if

the

high, since the sludge tends

at higher temperatures.

when first immersed in all processremoved to the next bath, and to keep the rinse and fixing baths acid. The scum can be removed while the film is still wet by wiping the surface with a cotton pad or a chamois,

The remedy

ing baths

but

it is

on the 6 "

and

is

to agitate the film

at intervals until

removed only with great

difficulty after being allowed to

dry

film.

A

Method of Testing

Picture Films" by (April 1930).

J.

I.

for the

Crabtree and

Presence of Sodium Thiosulfate in Motion /. Soc. Mot. Ptct. Eng. 14, 419 F. Ross.

J.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

190

Drying o£ Photographic Materials The

usual difficulties encountered

at

High Temperatures.

when drying

films or plates at high

temperatures when high humidities prevail are a result of excessive swelling of the gelatin.

more water

the

it

It is

obvious that the more the gelatin

is

swollen,

contains, and the longer the time required for dry-

ing or evaporation of this water.

The

use of a concentrated developer

necessary containing sodium sulphate) and of a chrome alum hard-

(if

ener rinse bath assists greatly in preventing abnormal swelling of the film

and

in

avoiding a prolonged time of drying.

of the image,

which

is

often produced

high temperatures, does not occur

Excessive graininess

by slow drying

if

the gelatin

of swollen film at

prevented from

is

swelling.

The drying power

of air increases rapidly with the temperature

but

the air entering the drying cabinet should be at a temperature which

is

no higher than that necessary to dry the film in the time permitted. The maximum safe temperature depends on the degree of swelling and

As the temperature

hardening of the emulsion. tive

humidity

is

lowered so that

its

greater the higher the temperature of the to the extent to safely.

and

air.

There

is

is

a limit, however,

which the temperature of the drying air can be raised a. the degree of hardening and swelling of the

This depends on

gelatin, b. the " air,

of air is raised, its rela-

capacity for water absorption

c.

dry bulb

"

the air velocity.

temperature and relative humidity of the LTsually the temperature of the air should

not be raised to such an extent that the " wet bulb " temperature exceeds 95°F. (35°C.).

In order to insure rapid drying,

it is

most important

renewal of the air in contact with the film surface.

A

to obtain rapid

small volume of

high pressures striking directly on the surface is much more effecthan a large volume of air moving slowly past the film. tive on handling amateur and professional films at high information Useful

air at

temperatures

is

and " Handling Motion Picture Film in Eastman Kodak Co., Rochester, N. Y.

Development " the Tropics," published by the

contained in the booklets

" Tropical


CH.XPTER IX

STORAGE AND TRANSPORTATION OF CHEMICALS AND SOLUTIONS The

selection of suitable storage conditions for solids

and liquids con-

cerns primarily the large user of photographic chemicals and not the

amateur who

is

accustomed

many

Nevertheless,

to

buying chemicals

in small quantities.

of the criteria for storage apply to both classes of

consumers. Storage conditions for dry chemicals are determined

b)^

two

factors,

namely, the relative humidity of the atmosphere and the temperature.

Certain chemicals tend to absorb moisture from the air and are

said to be deliquescent, while others lose moisture

The

efflorescent.

and are classed as

extent of the absorption or loss of moisture

is

de-

termined by the relative humidity and the temperature.

much unknown composition and many powa damp atmosphere.

very important that chemicals should not absorb or lose

It is

water, otherwise they have an

dered chemicals tend to cake in

The temperature of the storage compartment should be moderate. Most solid chemicals are unaffected by temperatures varying from 32 °F. (o°C.) to iio°F. (43 °C.), but liquids tend to expand when heated and freeze when cooled and it is important, therefore, to use greater care in For winter storage, liquids should not

choosing their place of storage.

be placed too near steam pipes or radiators or other sources of heat, and in summer they should not be placed where direct sunlight may fall on

them.

Chemical Storage Room.

— The

space chosen for the storage of

chemicals should be located in or preferably adjoining the chemical mixing room.

It

should be situated some distance from rooms containing

sensitive films or plates

and

also

from the developing room

in order to

avoid contamination of the sensitive materials with fumes or gases given

off

by

liquid chemicals

and solutions, and the formation

or stains arising from chemical dust settling

during processing

(see

discussion

of spots

on the sensitive materials

on page

18

and Figure

5,

page

23)It is

good practice

used for chemicals.

to separate the storage

The

room

following substances are

for film

known

to

from that

have a harm-

ful effect on dry undeveloped films or plates and usually produce fog on subsequent development of the sensitive materials:


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

192

Hydrogen peroxide Volatile oils and solvents

1.

2.

a.

Turpentine

b.

Benzol

c.

Oil of cloves

d. Oil of e.

Some

lavender

used in paints

oils

3.

Ether

4.

Ethyl acetate (used

5.

Coal gas and illuminating gas

in varnishes

and lacquers)

Hydrogen sulphide Ammonia.

6. 7.

Adequate ventilation and the chemical storage

exit facilities

and mixing rooms.

should be provided for both

Their

air

systems should be

designed so that the fresh air tends to enter (rather than leave) the

mixing room from the other processing rooms. provided in the mixing room to carry the

Exhaust fans should be

There

air directly outdoors.

is

always a danger of some employee breaking a carboy of acid while handling

and

of being

of the room. to

them kept

A

overcome by poisonous fumes before he can get out

Exits should be

marked

plainly

and passage ways leading

clear.

shower operated by a quick acting valve should be provided

quantities of acid are being used.

This scheme

is

if

large

utilized in all large

manufacturing plants and technical laboratories as the quickest and most effective

means

of first-aid to prevent acid burns.

rooms should be provided with a good

All chemical storage if

possible, to permit

floor drain,

accumulated (see Figure 23, page 43). Chemicals should be marked carefully and stored only places in the room.

Employees should be cautioned

labels carefully before mixing, because

casual inspection. result

may have

washing away any chemical dust which

many

to

chemicals look alike on

Trouble from incorrect mixing and

from mistakes made when selecting the chemicals

developer or fixing bath.

A

little

in definite

examine the

lost

may

batch of

time spent in insuring cleanliness and

order in the chemical storage and mixing rooms will be repaid

hours of time saved

time

for a

in the processing

by many

room.

THE STORAGE OF CHEMICALS AND SOLUTIONS Chemical Storage.

â&#x20AC;&#x201D; As noted

previously, chemicals for amateurs

They are

usually purchased in small packages

are seldom stored in bulk.


STORAGE AND TRANSPORTATION which contain the exact weight of chemicals necessary definite

mon

volume

The types

of water for use.

193

for dissolving in

of containers in

a

most com-

use are: small glass tubes, cartons, metal cans, and cans with metal

Waxed paper

top and base and cardboard paper tube sides.

liners or

bags are often used for the cartons and waxed corks for the glass tubes.

When

very corrosive materials are placed

in glass tubes, as in the case

some reducer chemicals, an asbestos or glass wool plug is usually In recent years, molded placed between the chemical and the cork. of

phenolic condensation products such as bakelite are being used for caps

and cans. Advanced amateurs, camera

for tubes, bottles,

and professional

clubs, photofinishers,

photographers who use larger quantities of chemicals usually buy bulk chemicals from which they can prepare their stock solutions.

consumers, chemicals are packed

in quantities

up

For such

pounds (2^

to 5

kilo-

grams).

Larger quantities for use by professional photographers, photo-

finishers,

motion picture and x-ray laboratories,

etc.,

laminated fiber drums (25 to 100 pounds capacity)

grams).

Hypo

is

packed

in several

(45 kilograms), in wooden

ways:

in

are supplied in

(ir to 45 kilo-

wooden kegs (100 pounds)

barrels (about 350 pounds) (160 kilograms),

bags (100 and 200 pounds capacity) (45 to 90 kilograms). This system of packing a definite weight in a bag, barrel, or drum sim-

and

in cloth

plifies

the mixing considerably, as

number

of such units

definite volume.

and add

it is

only necessary to count out the

their contents to the

tank when mixing a

Thus, the time required for weighing

For many types of work, chemicals in their original

is

avoided.

more convenient to leave the containers and to use a scoop when removing

small quantities for mixing.

is

it

A

usually

tilting bin represents a useful storage

pounds (45 kilograms) or less. It is not satisfactory for large quantities because the heavy bin becomes strained and broken if allowed to fall back into place by gravity. A

compartment

for quantities of 100

wooden box with

may

and castors which ride on metal tracks Such a storage compartment may be slid under

a hinged cover

be used (Fig. 78).

a bench when not in use. ]Most chemicals are affected

by

air

which contains oxygen, carbon

dioxide gas, and moisture.

A. Oxygen readily attacks such substances

as

cially in the presence of moisture, converting

it

which

is

useless as a preservative.

With

sodium into

crystallized

sulphite, espe-

sodium sulphate, sodium sulphite,

the sodium sulphate forms on the outside of the crystals as a

which

may

be washed

off

and the crystals

dried.

It

is

less

powder easy to


PHOTOGRAPHIC CHEIVHCALS AND SOLUTIONS

194

detect sodium sulphate in desiccated sulphite except

by chemical

tests.

Other substances which combine with oxygen and are therefore said to

be oxidized are sodium bisulphite and potassium metabisulphite,

and all developing agents such more or less brown, the extent

as pyro, hydroquinone, etc., of the color

which turn

change roughly indicating

the degree of oxidation.

Storage compartment for solid

Fig.

chemicals

B. Carbon dioxide gas combines with substances

like caustic

soda

and caustic potash, converting them into the corresponding carbonated alkalis which are less reactive. If caustic soda is kept in a glass stoppered bottle, the stopper usually becomes cemented fast by the sodium carbonate formed, so that cork.

Owing

it

should be kept

with a waxed

in a bottle fitted

to the solvent action of the caustic alkalis

on

glass, the

inside of the glass bottle containing caustic or strongly carbonated solutions

becomes

will usually

C.

When

frosted,

though the amount of glass thus dissolved away

do no harm. exposed to a

damp

atmosphere, the

alkali,

Kodalk, tends


STORAGE AND TRANSPORTATION carbon dioxide gas with a corresponding

to absorb

With reasonable difficulty

cals

due

care,

by storage

in the original

to loss of activity will

have a strong attraction or

atmosphere and gradually dissolve This phenomenon

a solution.

is

loss of alkalinity.

covered containers, no

in the

moisture present in the

water thus absorbed, forming

termed deliquescence and the chemi-

Familiar examples are

cals are said to deliquesce.

Certain chemi-

be encountered.

affinity for the

195

ammonium

thio-

cyanate, potassium carbonate, sodium hydroxide, potassium hydroxide,

sodium sulphide, uranyl be stored

in

It is possible to

a chemical

hydrometer readings

book

by N. A. Lange or the

edited

in

etc.,

which should

melted paraffin wax.

prepare a solution of definite percentage strength from

typical good reference

Journal

sodium bichromate,

which has deliquesced, by the use of a hydrometer, referring

to a table giving the

A

nitrate,

corked bottles and the neck dipped

is

in

the "

terms of percentage strength.

Handbook

Chemistry

of

" *

tables given in every issue of the British

Almanac^

D. While some chemicals absorb moisture as above, others give up water of crystallization to the atmosphere and therefore lose their

their

and fall to a powder and are then said to effloresce, phenomenon being termed efflorescence. Some crystals do not contain any water and therefore cannot effloresce. Typical efflorescent

crystalline shape

the

salt.s

A

are sodium carbonate .loH.O, sodium sulphate .loH.O, and hypo.

very dry atmosphere

but not for efflorescent

idly

The only

for storing deliquescent salts

satisfactory

way

to store chemi-

to isolate

is

when made up

Silver nitrate

darken is

most favorable

them from the air by sealing in a suitable manner. E. There are some chemicals which are decomposed by long exposure Such chemicals usually change more raplight, especially sunlight.

cals

to

is

salts.

in light

to store

or else

The

is

as a solution than

when

stored in the solid form.

probably the outstanding e.xample.

and

a solution will

both the solid and

Crystals of this salt

darken quite rapidly.

liquid in a

The remedy

cupboard away from the

light,

cover the bottle with black paper or opaque paint. use of brown bottles, as often recommended,

is

not necessarily

a protection of the liquid or solid from the action of light unless the absorption properties of the glass are such as to stop all harmful rays reaching the solution.

Publishers, Inc., Sandusky, Ohio, 2nd edition, 1938. Almanac are printed on the British imperial quart

*

Handbook

t

All formulas in the Brit. J.

or gallon basis and re<iuire conversion

The metric values

(see page 7)

given, however, are universal.

for use in the United States.


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

196

Solution Storage.

â&#x20AC;&#x201D; Most

in glass bottles or in carboys.

liquids used for

photography are shipped

Solvents for cleaning film and for splicing

are usually supplied in metal (tin) cans and in metal (galvanized iron)

When emptying

barrels or drums.

should be used.

liquid

from a carboy, a carboy rocker

There are several types of these rockers but the gen-

â&#x20AC;&#x201D;

FiG. 79 Hard-glazed stoneware crocks for solution storage. Note stainless steel drip tray and

type of outlets on crocks and storage tank (right) eral principle of each

is

similar,

namely, a cradle holds the carboy crate

and permits gradual, smooth tipping liquid contents.

It

is

when removing the empty Most industrial acids.

of the carboy

dangerous practice to use

carboys containing corrosive liquids, such as

air pressure to

plants prohibit such practice in their safety code.

Small volumes of solution

may

be stored in tanks

earthenware, hard rubber, enamelled

32A and 32B, pages tainer

is

steel,

made

of glazed

rubber lined steel (see Figs.

A

63 and 64), or glass.*

a crock of hard glazed stoneware as

convenient storage con-

shown

in

Figure 79.

All

stock solutions should be mixed in a separate container and then added to *

See Appendix, Part

materials and equipment.

III,

page 341, for a

list

of manufacturers of construction


STORAGE AND TRANSPORTATION A

the storage crock or bottle. of 18-8 stainless steel are

satisfactory mixing tank

shown

in

Figure

4,

page

welding the joints when constructing stainless

and

is

discussed in Chapter

page 64.

I\',

A

steel

197 stirrer made The method of

and

22.

tanks

is

important

suitable outlet should be

provided near the base of a stoneware container but a little space should be left below the outlet to allow any foreign matter to settle to the bot-

tom

of the container rather than run out through the outlet.

Fig. So

The method

â&#x20AC;&#x201D; Battery

of stoneware tanks.

of attaching the outlet

is

important.

If

not supplied

with a hole slightly above the base, the crock should be drilled. A soft rubber stopper with straight rather than beveled sides and having a center hole should be fitted snugly into the outlet.

A

hard rubber tube

and hard rubber faucet should be fitted tightly into the hole in the soft rubber stopper (see right hand crock in Fig. 79). The diameter of the hole in the soft stopper should be slightly smaller than the diameter of the hard rubber tube to assure a tight

sometimes advisable

to attach a

fit.

clamp

As a double precaution,

it is

to the outlet so designed as to

extend over the edge of the outlet and the top of the stopper. This type of outlet has several advantages, namely: it is i. non-corrodible, 2. resistant to breakage,

An

and

3. easily

removed

for cleaning.

alternative outlet consists of a right angled lead tube inserted

through a rubber stopper.

An

18-8 stainless

steel or a

should be fastened around the jar as shown on the

Monel metal band

left

crock in Figure


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

198

79 to hold the stopper securely in place. A short length of pure gum rubber tubing may be fastened over the lead tube and closed by means of a screw

clamp or a pinch clamp.

Large storage tanks of lOo gallon capacity or over should have a hole

bottom

in the

fitted

ing of the tank.

with a tapered wooden plug to facilitate easy clean-

This outlet

may

If a strongly caustic developer

also serve as the delivery pipe.

is

to be stored in a crock, a glass tube

or a hard rubber faucet should be used rather than a lead one, since the alkali

may

and form a

react with the lead

Glass outlets

precipitate.

should be avoided whenever possible because of the danger of breakage

and

of cutting the

It is

hands when

on the surface of a solution so as cedure

is

to protect

not recommended, however, as

may

material into the developer which it

tube into the rubber stopper.

fitting the

sometimes suggested that a layer of refined mineral

empty crock

leaves an

scheme

it is

it

from the

This pro-

apt to introduce a foreign

lead to trouble from spots, while

A much more

in a dirty condition.

Kodapak to lit the container and float made of 18-8 stainless steel.

A

on the surface.

it

practical

Kodaloid or

to construct a shallow boat of thin sheets of

is

be poured

oil

air.

boat

may

also be

When

a battery of stock solution crocks or bottles

18-8 stainless

table, a small

arranged on a

is

Monel metal trough should be

steel or

tached to the table edge to catch the drippings (Fig. 79).

good practice

to provide a floor sink

because an entire building

example,

if

under the table holding the crocks,

may become

inoculated with hypo dust, for

a large crock or bottle containing

and the contents allowed

to seep

stock solution bottles or crocks

with sheet lead or white

may

be

made

vitrolite.

by prolonged exposure

hypo were

through the

Action of Sunlight on Stock Solutions. are affected

at-

It is also

of

to

be broken

Table tops for

floor.

hard maple covered

â&#x20AC;&#x201D; Some stock

to direct sunlight.

solutions

Potassium iodide

solutions, for example, often turn a deep yellow color because of the

liberation of free iodine.

on standing

in

Nitric acid sometimes turns yellowish-brown

white glass bottles for long periods of time.

Potassium

ferricyanide also turns blue due to the formation of Prussian blue. lutions of this type are best stored in dark cupboards located direct sunlight.

Storage of Large Volumes of Solutions.

So-

away from

â&#x20AC;&#x201D; Deep tanks

of

hard

glazed stoneware are very satisfactory for storage of large volumes of solution.

B

is

A

typical battery of such tanks

a smaller stone tank, and

C shows

is

shown

at

A

in

Figure 80.

the slatted platform on which the


STORAGE AND TRANSPORTATION tanks rest above the mastic a hypo tank

made

A solution Figure 8i.

lloor,

mixing room

in a

is

shown

in

mixing the chemicals

is

Each

barrel

is

The

with a dust-proof cover.

modern photofinishing plant

of barrels used for

equipped with power driven

Fig. 81

D

thus permitting easy washing.

of cypress.

The upper row

storage units.

The lower row

stirrers.

made

mixing room on a larger scale

represents the solution mixing

tanks on

The

the floor below.

A

schematic diagram

moderate

size

is

shown

is

fitted

is

room

shown in

Note

in

Courtesy

Calif.

Figure 82.

This picture

a motion picture laboratory in

by gravity

to the circulating

Every tank wooden cover being

the portable mixers in use.

should be covered, whenever possible, a laminated in

and

in a photofinishing plant.

solutions are fed

very effective as illustrated

represents the

of oak, holds 48 gallons,

â&#x20AC;&#x201D; Solution mixing and storage room

Hollywood, Calif.

is

large tanks are of 250 gallon capacity.

Bear Photo Service, San Francisco,

A

199

Figure 36, page 71. room for a photographic plant of

of a mixing

in Figure 83.

The

fixing

bath tank

is

located on

one side of the chemical storage room, which permits the hypo to be handled and mixed in a separate room from that where the developers are prepared. Developer chemicals are moved on a small elevator from


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

200

the chemical storage

room on

the upper left into the mixing room.

The

weighing bench, sink, and mixing and settling tanks are located on an

A

elevated platform, approximately 3 feet above the floor of the room.

runway extends

room from

across part of the

tween two rows of mixing tanks.

the weighing bench be-

Portable mechanical stirrers

used to mix the solution (see Fig. 10, page 27).

Sulution mixing

room

in a large

Metro-Goldwyn-Mayer,

been mixed and allowed to

clear,

motion picture laboratory Hollywood, Calif.

either side

is

it is

by gravity

fed

into the adjoining

Another sink with a bench on

located at the opposite side of the mixing

venience of mixing smaller volumes of chemicals.

adequate ventilation

facilities

Courtesy

Inc.,

storage or feed tanks on the floor level.

be provided

in the

It

is

room

for con-

important that

mixing room.

very satisfactory material for protecting the outlet of large stone-

ware tanks

is

called " superflexite." *

It is

a hard semi-flexible lami-

nated rubber compound that gives a tightly sealed

When

washing down the

to see that the

wooden

tanks.

false floor of a

slats receive

cals tend to crystallize out

solutions

is

it is

important

spilled over the sides of the

picked up on the shoes and

room where

and produce spots on the

joint.

mixing room,

a thorough flushing because chemi-

from solution

Later this chemical dust

carried into the developing

*

be

Ww

R

A

may

After the solution has

it

will tend to

film.

Supplied by B. F. Goodrich Co., Akron, Ohio.

may

be

contaminate the


.

STORAGE AND TRANSPORTATION

201

Another useful type of storage or mixing tank is a glass-enameled tank which is made by fusing a resistive silicate enamel on to steel

steel

shells.

Such tanks can also be obtained with either

vertical or hori-

zontal agitators installed (see Chapter IV, page 58).

OFFICE OR

TESTING

Fig. 83

LABORATORY

Diagram of chemical storage and mixing laboratory.

Quite satisfactory tanks for moderately large volumes of solution can

be built of a cheaper wood than cypress, such as pine, and coated on the inside and partly on the outside with a layer of oxygenated asphalt (see Chapter IV, page 66)

Black iron has also been used with satisfaction for use with developmoderate alkalinity. Iron or steel tanks may also be lined with

ers of

hard rubber.

The

coefficient of linear

expansion of hard rubber within

a temperature range of 32° to i40°F. (0° to 6o°C.) according to Fritz

and Hoover

^

is

from three

to five times that of steel.

temperature changes are encountered, the rubber

Therefore,

may

crack.

if

rapid

To

offset

1 " The Chemical Resistance of Rubber as an Engineering Material " by H. D. " Symposium on Rubber " published by Amer. Soc. for Fritz and J. R. Hoover. Testing Materials, Philadelphia, Pa., page 113, 1932.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

202

this disadvantage, a three-ply rubl^er material has

consists of a layer of hard rubber cushioned

new type to

which

immune

soft

84 make

this

Overlapping expansion joints as shown

rubber.

been built up which

between two layers of in Figure

of construction material a very practical lining for steel tanks it

can be bonded with suitable cements so that

to physical

it is

remarkably

damage.

Two-ply rubber coatings on iron or steel are and trays. Soft rubber

linings of tanks, pipings,

also satisfactory

bonded

is first

for

to the

metal and then a layer of hard rubber laid over the soft rubber.

MM Soft Rubbe.r Hard Rubber SX3 M£TAL Cxp/\N5ioN Joint :r

Fig. 84

— Diagram of an

expansion joint lor a laminated rubber sheet.

Soft rubber sheeting should

first

be tested to insure that a precipitate

does not tend to form on prolonged contact with developing solutions (see

Chapter IV, page 66).

Storage tanks for strong oxidizing solutions such as acid permanganate or acid bichromate used in photographic reducer formulas require the use of glazed earthenware or acid-proof brick linings in iron tanks or rubber-lined steel tanks.

Alberene stone

may

be used effectively for building moderately large

tanks to hold developers but hard glazed stoneware or wood tanks should

be used for fixing baths.

For a general summary of the most

tory materials for tank construction, reference should be 3,

Chapter IV on pages

made

satisfac-

to

Table

74, 75.

TRANSPORTATION OF CHEMICALS AND CIRCULATION OF PHOTOGRAPHIC SOLUTIONS Conveyances for Moving Chemicals in Bulk. moved with small handtrucks, which

chemicals can be

— Most

bulk

should be of

sturdy construction, fitted with smooth running wheels

(preferably

equipped with

a

roller bearings)

tendency for crates, barrels,

and

so designed that there

etc., to tip off the truck.

is

minimum

It is especially

important when handling carboys of acid to use trucks which move

smoothly and hold the carboy rigidly

in place

during transit, as serious


STORAGE AND TR.\NSPORTATION burns often result trouble of

may

hypo

and

a strong acid

if

is

spilled

also occur, for example,

if

on the body or

Where

on the

film.

several units of chemicals are to be

This consists of

effective.

moved, a dual system

may

platform

is

is

a low, sturdy platform, usually called a

i.

"skid," on which the boxes or barrels are piled, and

a

2.

truck

lift

be run under the platform and then raised until the entire lifted clear of the floor.

mix

cals necessary to

unit from the storage

With such a

device,

a batch of developer can be

room

all

the chemi-

moved quickly

as a

into the mixing room.

often necessary to raise barrels or

It is

INIuch

feet.

the dust from a broken barrel

gets into the air circulation system of a processing laboratory

settles

which

203

drums containing chemicals

several feet from the floor to a platform surrounding the mixing tanks. If the elevation

is

only one or two

feet,

an inclined runway

With

and the containers wheeled up on a truck.

is

A

however, some sort of hoist must be installed.

feet,

it

hoist

also

is

is

quite slow in operation.

very effective; while

hoist operated

When

air

may

if

time

is

may

be used

a factor, an electric

a source of compressed air

is

available, a

be utilized.

handling chemicals on a large scale, a portable elevator more

commonly Stackers

by

If

be built

block and tackle

perhaps the simplest and most economical hoist which

but

may

elevations of several

called

may

" stacker

a

be obtained

in

""

represents an

many

styles

and

efficient

sizes

type of hoist.

from simple types

which are manually operated by means of a winch to the more complex types which are electrically operated and have large lifting capacities.

Methods oÂŁ Conveying Solutions. veying solutions

is

by gravity with

â&#x20AC;&#x201D; The simplest method

of con-

A

the aid of suitable piping.

good

grade of rubber tubing represents, perhaps, one of the cheapest types of installation, but care

insure that

it

must be exercised

encountered when using is

it

more satisfactory than

to

soft

cation in chemical industries.

convey developers.Its chief

ported by a trough or brackets pipe line which

iron pipe which

mum

is

is

Hard rubber piping

rubber tubing, and has found wide appli-

and may break under the impact

A

in selecting tubing in order to

does not contain free sulphur or trouble from fog will be

of a

if

disadvantage

heavy blow.

is

that

It also

it

is

brittle

must be sup-

long lengths of pipe need to be used.

not subject to this trouble

is

hard rubber lined

supplied in standard lengths and diameters (mini-

^ inch) and with

all

types of fittings.*

The connections

are de-

Chemical Fog " by J. I. Crabtree. Amcr. Aim. Phot. 33, 20 (1919)by such firms as B. F. Goodrich Co., Akron, Ohio, and U. S. Rubber Co., New York, N. Y. -

"

* Supplied


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

204

signed so that the solution never comes in contact with the iron at any

point during transit.

Wooden

troughs built of untreated cypress or of a cheaper

coated with Kodacoat paint or with oxygenated asphalt for

wood and

may

be used

conveying solutions down a slight incline from one point to another

on the same

floor.

to collect dust or

These are subject to leakage occasionally and tend any other foreign matter accidentally dropped in the

trough.

Fig. 85A

— Air

lift

solutions.

for photographic

Tank

Fig. 85B

Use of Compressed

Air.

— Air

lift

solutions.

closed.

— As a general

for photographic

Tank

open.

practice, air under high

pressure should not be used for conveying solutions through pipe lines. It

should never be used for the movement of strong acids or alkalis, as

very serious accidents have resulted from the spraying of corrosive acid

on workers as a

when

ever,

ume

result of a

of solution quickly

tance

is

break in the

air pressure offers a simple,

not too great.

from one

line.

There are occasions, how-

convenient means of moving a vol-

level to a higher level providing the dis-

For example,

it

may

be necessary to locate the

circulating or feed tanks for a small motion picture

machine as high as


STORAGE AND TRANSPORTATION

205

possible from the floor in order to create

enough head to provide adeMixing should then be carried out on the floor and the solutions blown by air pressure from the mixing crock to the

quate flow of solution. level

tanks.

A

An

installation of this type

hard-glazed stoneware crock

keted stoneware cover

Fig.

is

85c

fitted

raised.

shown

fitted

in Figures

85A and 85B.

on when the solutions are ready to be

of

molybdenum

with an to the floor above. is

is

used for a mixing vessel and a gas-

â&#x20AC;&#x201D; Installation

structed of 18-8

tank

is

mixing tanks constainless steel.

Each

air lift for raising the solution

Air pressure of 6 to 10 pounds per square inch

is

applied through

a good grade rubber hose connected to the orifice in the cover. tion outlet

is

near the base indicates the level of the solution. to use air pressures

A

The

solu-

located near the base of the crock and a small glass gauge

much above

It is

not safe, however,

15 pounds per square inch.

complete installation of mixing tanks, mixers and piping made en-

tirely of

gasketed

18-8 molybdenum stainless lid is

clamped down

steel

is

shown

in

Figure 85C.

after each solution has been

The

mixed and,

air pressure (about 9 pounds), the solution is forced into the storage tanks on the floor above. Gauges on the wall indicate the

by applying

solution level in all storage tanks on the upper floor.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

206

Pumps.

â&#x20AC;&#x201D; When â&#x20AC;˘

movement

the

common

it

not feasible to use gravity or air pressure for

is

pumps

of a solution,

may

types

The most

are usually employed.

be classified into three groups, as follows:

ciprocating or piston pumps,

2.

centrifugal

pumps, and

3.

i.

re-

rotary or gear

pumps.

pump is effected by shown in Figure 86A. An intermittent flow results since the piston movement is reversed alternately. All reciprocating pumps use valves and require packing, and 1.

The

delivery of the liquid in a reciprocating

the displacement of a piston or plunger as

have an advantage over the centrifugal type require priming except the

first

in the fact that

they do not Centrif-

time used after installation.

ugal and rotary pumps, on the other hand,

may

be installed and op-

erated usually at a lower cost and are preferable, therefore, to recipro-

pumps for handling photographic solutions. The mechanical construction of a centrifugal pump is extremely simple. The only moving part is a rotor or impeller which turns in a stationary case. The rotor is surrounded by a spiral casing (the volute) The of gradually increasing cross section, as shown in Figure 86A.

cating 2.

pump is relatively free of pulsations. pump must be primed each time it is started.

flow of a centrifugal

A

centrifugal

not develop as high a suction

lift

tion of that of the reciprocating type for the less.

It

only a frac-

same duty.

Initial cost

can be connected directly to an

or belt drive as required.

The capacity

and the head varies with the square

mended

the

is

other hand, the size and weight of a centrifugal

and upkeep are

pump

It will

On

pump.

as the reciprocating

electric

motor

varies directly with the speed

of the speed.

This type

for use with photographic solutions provided

it

is

is

recom-

constructed

of a corrosion resisting material such as hard rubber or 18-8 stainless steel or

Monel metal.

Rotary pumps consist essentially of two closely fitting gears which, turning, carry the liquid around their peripheries as shown in Fig-

3.

in

ure 86A. often used

Because of the simplicity in

in

their design,

These pumps depend

They can handle

for their lubrication

on the liquid being pumped.

two types.

No

liquids containing grit or solids,

ever, should be used as the small clearance of the solid material to pass.

18-8 stainless

by how-

viscous liquids which cannot be handled effectively

either of the other

any

such pumps are

handling photographic and other chemical solutions.

steel, or

photographic solutions.

This type of

Monel metal

is

pump

if

pump made

will not

permit

of hard rubber,

very satisfactory for use with


.

STORAGE AND TRANSPORTATION A

,

novel valveless

which

is

adapted

to

pump

moves)

has been developed by Bennett

A

flexible

Three common types of pumps.

The

mounted on a

Fig. 86b

cast iron panel.

â&#x20AC;&#x201D; Bennett valveless pump.

part corresponding to the impeller of an ordinary

of a circular disc

mounted on

three ball-bearing rollers capable of radial adjustment.

A

pump.

" tractor

When

rollers

rollers are

small clearance about equal to the thickness of

the spindle

rubber tube, the

The

consists

mounted

path," an important

the compressed rubber tube exists between two of track.

pump

a driving spindle and on this are

circumscribed by a flexible band called a feature of the

(London),

rubber tube (through which the solu-

against a curved track,

lies

*

handle liquid and gases without bringing them into

contact with metal. tion

207

is

the rollers and

rotated, the tractor path sweeps along the

compress the tube, and cause a small volume of

between the two rollers to move forAt the same time, a fresh charge is drawn in be swept out by the third roller. The pump is self-priming and the

liquid in the section of the tube

ward toward the to

outlet.

may be replaced quickly Fig. 86B pumps should always be flushed out carefully with water each time they are shut down after use to remove any liquid remaining in the

rubber tube or pumping element

(

)

All

pump chamber. should be 3

"

A

made

Valveless

For further details on to the

Pump

"

pump

pump

installation,

reference

manufacturers (see page 343).

by C. M. Bennett.

lud. Chemist 11, 274 (July 1935).


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

208

Siphons.

— Another well-known device

the siphon, which in

is

its

for the

movement

of liquids

simplest form consists of a bent tube used for

carrying the liquid from a higher to a lower level over some intervening obstacle as

shown

Assuming that the tube

Figure 87.

in

the liquid, as long as h^

is

soon as these distances become equal, than

Fig.

h, the flow will

— Diagram

87

of

it

The

be reversed.

a

is filled

with

greater than h, the flow will continue but as

simple

will cease or,

if

h^

becomes

less

distance h must not be greater

Fig. 88

— Two

types of siphons.

siphon.

than the height of the barometric column

This

— about

34

feet for water.

portional to the size of the siphon.

when the The rate of flow is inversely proWith long siphons, the diameter of

the short pipe should preferably be

much

is

a theoretical distance; practical siphons operate only

distance h,

is

not greater than 28

feet.

larger than the long pipe to

secure a satisfactory rate of flow.

Two

simple types of siphons are shown in Figure 88.

by compressing the rubber bulb

just previous to

Type A works

immersion in the vessel

The bend of the tube at the by adding some of the liquid to it. When the bulb is released, the suction created draws the liquid in the vessel through the column and starts the siphon. Type B starts itself by simply immersing the tube S in the liquid chamber R. The liquid fills the narrow tube T which must be im-

containing the liquid to be siphoned over. discharge end

mersed almost ing this

Y

X

is

sealed off

to the bend.

into the larger

chamber gradually

and the bubbles

The

chamber fills

of air rise

S,

liquid also flows through the open-

which surrounds the tube T, and as

the air

is

forced out through the opening

through the column of liquid

in the

tube T.


STORAGE AND TRANSPORTATION Since the weight of the liquid and air in the narrow tube

weight of the liquid height

immersed, pressure

is

in the large vessel in

siphon

If the

pushed out of the chamber

liquid emptied out,

is less

it

is

is

forced

before

all

the

must be removed,

all

the

fails to start

the siphon

S,

than the

which the siphon

exerted on the liquid in the tube and

over the bend of the siphon. air is

20Q

and the tube reimmersed.

FEED TANK

CONTINUOUS r\_ow

SYSTEM OeVELOPtNG.

MACHINE

Fig.

â&#x20AC;&#x201D; The

continuous flow method of solution circulation.

In

many

types of continuous machines,

it

is

desirable to install an

automatic means for adding replenisher and maintaining the solution level in various tanks.

Hickman

*

has described several such devices

which incorporate modifications of the siphon principle. Circulating Systems. For most types of photographic work

â&#x20AC;&#x201D;

which are carried out manually,

it is

unnecessary to circulate the solu-

done intermittently and replenisher needs to

work is when required. Automatic processing machines, however, run continuously when in use and the films are carrying a fairly definite tions because the

be added only

volume of solution out of each tank as well as exhausting the solution by virtue of the developing (fixing, hardening) process. With such 4 " Siphons and Measuring Devices for Photographic Solutions " by K. Hickman. Trans. Soc. Mot. Pict. Eng., No. 26, 37 (Nov. 1926).


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

210

equipment

it is

customary practice

to arrange to feed solutions into the

processing tanks at such a rate that the volume level will remain nearly-

constant and the strength of the bath will

as little as possible

fall off

on developer exhaustion, Chapter VTI, page 132). general systems are in vogue for the addition of solutions

(see section

Two

matic processing machines, namely:

a.

to auto-

the continuous flow system and

the recirculating system.

b.

A. The continuous flow system represents the simplest instaflation problem since the scheme does not require the use of the solution more than once. As shown in the diagram (Fig. 89), the solution is fed, either by gravity or by means of a pump from the mixing tank through the feed tank and cooling coil into the machine. The point at which it enters the machine varies according to the nature of the developer and the type of film being processed. With negative film, it is advantageous to flow fresh developer into the machine at the point where the film enters, and allow the solution to flow out where the film leaves the machine. This scheme assures that development starts in a fresh developer and shadow details begin to appear before the film enters parts of the machine where the developer is partially exhausted.^

When

handling positive

film, this

as the absolute speed value

is

system

is

not quite so advantageous,

of less importance than the securing of

uniform prints by virtue of the maintenance of constant development conditions.*^

ample,

it

When

using a developer containing no bromide, for ex-

might be advantageous to feed the developer

where the solution leaves the tank so the solution

in at the point

will

be uniformly

conditioned at the point where the film enters the machine. will dictate

which system

]\Iost of the

is

photofinishing plants in this country and abroad, which

are using automatic machines, and tories,

some

of the

motion picture labora-

use an alternative procedure which consists in reviving the bath

at intervals with a replenishing solution

and composition from the

tion

Practice

best to follow.

which

original formula.

should normally be introduced at a rate which

differs

in concentra-

Replenishing solution is

proportional to the

quantity of film processed.

B.

]^Iost of the large

motion picture laboratories

abroad use a recirculation system shown 5

M.

"

L.

in this

in its simplest

country and

form

in Fig-

A Quick Test for Determining tlie Degree of Exhaustion of Developers " by Dundon, G. H. Brown, and J. G. Capstafif. /. Soc. Mot. Pict. Eng. 14, 389

(April 1930). 6 " Replenishing Solution for a Motion Picture Positive Film Developer " by

A

J. I.

Crabtree and C. E. Ives.

/.

Soc. Mot. Pict. Eng. is, (127 (Nov. 1930)-


STORAGE AXD TRANSPORTATION lire

The

90.

211

solution flows from the mixing tank into the feed or cir-

culating tank, and then

pumped

is

The

into the machines.

A pump

directed back into the circulating tank again.

is

overflow

is

necessary to

maintain the circulation and the solutions are usually piped through a cooling device located near or sometimes in the feed tank.

customary it

is

to

add replenisher

It is

usually

at intervals to the circulating tank

thoroughly mixed with the used developer before

it

where

enters the

OVCR-F-L-OW

Fig. 90

â&#x20AC;&#x201D; The

recirculation

method

of solution

circulation.

machine.

Alternately the replenisher

machine.

The

may

be added directly to the

point at which the solution enters the machine

pendent on several factors as explained above.

system

is

is

de-

The advantage

of this

fall off at

a rela-

that the developing properties of the solution

tively slow rate

depending on the capacity of the recirculating tank.

A

above, the rate of addition of replenisher must be ad-

With method

justed carefully

by

and

trial

error, so as to secure a constant rate of

development, otherwise the developer

in the relatively small

tank will

rapidly become exhausted.

The

cooling coils

culating tank as

may

shown

be arranged either around the sides of the

in

Figure 90 or the overflow

may

cir-

be cooled by

surrounding the pipe with a cooling chamber as shown at B in the Figure. The best location of an exterior chilling box obviously depends on the arrangement and size of an individual installation.

In some laboratories

it

is

not customary to circulate fixing baths or

rinse baths although a replenisher

the

life

of these solutions.

The

is

often added several times during

level of these baths

is

normally main-

by the solution carried over by the film from the previous bath. In the case of laboratories where silver recovery units have been in-

tained


— PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

212

stalled, the fixing

bath

is

recirculated

and

filtered

"

and

this insures

more

and Temperature control when using automatic machines is of utmost importance and all modern processing laboratories have means installed cleaner film.

efficient fixation

For a discussion of

for maintaining the temperature constant. ject, reference

should be

Fig. 91

Flow Meters."

made

— Types

It is

to

this sub-

Chapter V, page 98.

of flow meters

and controllers

frequently necessary to measure and control

the flow of solution in a pipe line, for example, during replenishment of

a developer or in a circulating system.

^Meters

may

be classified into

four types as follows: 1.

Rotameter

— Constant

Head and Calibrated

Orifice.

This type consists of a calibrated tapered glass tube containing a

float,

the position of which indicates the rate of flow through the tube.

constant head must be maintained and throttling

A

accomplished with

is

The capacity ranges from i cc (approximately 4 drams) to hundreds of gallons per minute (Fig. 91, upper right). A constant head on a calibrated 2. Float and Orifice Type. a valve.

~

and

"

The

W.

Electrolytic Regeneration of Fixing Baths " by K.

Weyerts.

/.

Soc. Mot. Pict. Eng. 17, 568 (Oct. 1931)

Hickman, ;

C. Sanford, also " Electrolysis of

Solutions" by K. Hickman, W. Weyerts, and O. E. Eng. Chcm. 25, 202 (Feb. 1933). * The authors wish to acknowledge the helpful assistance of R. B. Ellsworth of the Engineering and Maintenance Dept., Kodak Park, for much of the data in this Silver-Bearing Thiosulfate

Goehler.

section.

Ind.

&


STORAGE AND TRANSPORTATION maintained by a

orifice is

float

which controls a supply

213

inlet valve.

The

solution flows in at the top and the range varies from approximately

10 cc to an unlimited 3.

in a

per minute (Fig. 91, upper left).

—A

bafl float

tank controls the supply flow through an ordinary regulator valve type

(this

maximum

Ball Float Valve to Maintain Constant Head.

is

not shown in Fig. 91).

Mercury Manometer with Air Operated Diaphragm Valve. An orifice is inserted in the line of flow and differential pressures are

4.

measured by a mercury manometer with a float connected to a pointer. This meter is used preferably to measure large volumes of solutions although

it

is

factorily.

capable of handling fractions of gallons per minute satis-

It is

used extensively as a pneumatic controller with an air

operated valve in the line of flow, as shown at the bottom of Figure 91.

The above meters should

preferably be constructed of corrosion-re-

sistant materials such as glass or stainless steel.

Apparatus for Commercial Development of Motion Picture Film. for the

A

comprehensive discussion of apparatus

development of motion picture film

in

for

handling solutions

commercial laboratories has

been published by the Committee on Laboratory Practice of the Society of

Motion Picture Engineers.* 8

Report of the Committee on Laboratory Practice,

345 (April 1936).

7.

Soc. Mot. Pict. Etig. 26.


CHAPTER X

SUBSTITUTION OF CHEMICALS It is

poor economy to buy cheap chemicals for mixing photographic

Many

solutions.

hours of preparation for photographing a particular

scene in a motion picture studio, for example,

may

be wasted

laboratory uses a developer containing impure chemicals. loss of valuable time,

it

may

the

also be very difficult to duplicate a particu-

Such wasted time

lar exposure.

if

Besides this

may

be avoided by using only pure

chemicals supplied by a reputable manufacturer.

There

usually no

is

need, on the other hand, to purchase chemicals of the highest purity such as are used for the preparation of reagents in an analytical laboratory.

The

precision of

workmanship

possible in practical photography

sufficiently great to require the use of

Whenever

possible, solutions should be

cal

however, when the photographer

and

would be convenient

it

he had ample stock.

to

not

mixed with the particular

chemicals which are called for in the published formula. arise,

is

such chemicals.

is

Occasions

out of stock of a certain chemi-

be able to substitute another, of which

This chapter

stitution with reference to developers

will discuss the limits of

and

such sub-

The remarks

fixing baths.

will

usually apply also to solutions in general.

SUBSTITUTION IN DEVELOPING FORMULAS A.

The Developing Agent.

to replace

â&#x20AC;&#x201D; As a general

rule

it is

own

identical properties, because each developing agent has its teristics as

etc.

not possible

one developing agent by another and obtain a developer with charac-

regards rate of development, fog, color of image produced,

In some cases, however, a close approximation can be made, for

example, by substituting Elon by several times

phenol provided the developer

aminophenol

to

be dissolved.

is

its

weight of para-amino-

sufficiently dilute to allow

This applies either to an

enough paraElon or an

all

Elon-hydroquinone formula. If

para-aminophenol

is

substituted part for part for the Elon in an

Elon-hydroquinone formula and the activity of the developer creased by the addition of alkali, the effect of the alkali

is

is

in-

proportion-

ately greater on the hydroquinone than on the para-aminophenol, so

that a rapid hard working developer culty, proportionally is

used.

The

is

obtained.

more para-aminophenol

usual ratio

of Elon in the formula.

is

is

To

avoid this

required than

if

diffi-

Elon

four parts of para-aminophenol to one part


:

SUBSTITUTION OF CHEMICALS Characteristic

properties

agents are given in Table

7,

of

the most

215

commonly used developing

An

pages 216 and 217.

excellent discussion

of the properties of various developing agents will be found in the "

Photography

The

B.

â&#x20AC;&#x201D; Theory and Practice

Preservative.

â&#x20AC;&#x201D;

-

It is

"

by L.

P.

now customary

bisulphite for potassium metabisulphite weight

veloper or fixing bath formulas. the stability of commercial talline structure

and also

to substitute

by weight

a function of

is

in

is

very

little

may

actual

commercial sodium bisulphite; the

major portion of the sample consisting of sodium metabisulphite. able and

^

crys-

its

P\irthermore,

of its lack of moisture content.

these authors have proved by analysis that there

mercially dry sodium

sodium

in either de-

According to Harrison and Carrol

sodium bisulphite

sodium hydrogen sulphite present

book

Clerc*

bisulphite of satisfactory quality is

now

Comobtain-

be used in mixing formulas calling for either the meta-

bisulphite or the bisulphite.

A

very interesting discussion of the comparative properties of the

sulphites, metabisulphites,

and acid sulphites has been published by

Wall.^'

The

question

often asked as to the difference in action between

is

sodium sulphite and sodium bisulphite. Sodium bisulphite may be considered as a compound of sodium sulphite and sulphurous acid, and therefore reacts acid, while sodium sulphite

is

alkaline so that in the

case of a two-solution pyro formula where the pyro

A

solution

is

pre-

served with oxalic acid or sodium bisulphite, an equal weight of sodium sulphite

would not preserve so well since pyro oxidizes much more read-

ily in alkaline

than

in acid solution.

In the case of a one-solution developer containing, say, sodium sulphite, sodium bisulphite, and sodium carbonate, the bisulphite is converted to sulphite of

by

the sodium carbonate and an equivalent quantity

sodium bicarbonate

is

formed

Sodium

Sodium

Bisulphite

Carbonate

Sodium

~

Sodium

Sodium

Sulphite

Bicarbonate

bisulphite, therefore, neutralizes or destroys

an equivalent

quantity of sodium carbonate, thus reducing the proportion of alkali and, therefore, exerts

H. Greenwood & Co., Ltd., London, 2nd edition 1937. The Composition and Evaluation of Commercial Sodium Bisulphite " by J. B. Harrison and M. F. Carrol. J. Soc. Chcm. hid. 44, 127 T (1925). Amcr. Phot. 2 " Sulphites, Metabisulphites, and Acid Sulphite " by E. J. Wall. * 1

P.

an apparent restraining action, while the developer

"

16, 137 (19-22).


(

216

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS i-^^^.a

s

ou^gg

'g'Sbci'o

<23-:2-

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•^^^•c°

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^;< c

-2

>*-

se

o

C^O-^S

c

-^

^S

_g

c o

^S^3="

-^.S.SSiiO

iiiii f¥|ii

^i^i

o

I—

b

•ri-^^'S,

^j^o^l

J-

3

oj

X3 -5

" s

^

c c

-S

o .2^-2^

m

"5

<!

^iu>ic;'So>. .^o«cP^>. r^.SoDe^.S'-

c!>

oi

Q

*

« .^

o o

O tc t—

H » O P^ Pa

ri-

>

o<

<


SUBSTITUTION OF CHEMICALS A-

t:>

M

-^ °o

§

S

-^

£

1 Oh

It-5°o

/r-'i

v

-=

^"Sa

^

5

5

^'^

>

ii -3

tS iJ

S

S

:r=

-2 I K

S

S

i_Vi

i^'l^

-S

2

.>

6I

-2

C/3

^S

217

lt/)I-.fcf)

S-E=^-

V,

S E 2 P^

^ ° ^

.-H

=.

^ ^ JJ

u


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

218

keeps longer because some of the carbonate has been destroyed.

Now,

supposing we have a developer containing lo grams of sodium bisulphite, 10

grams

of

we should expect

sodium to get

sulphite,

and 20 grams of sodium carbonate,

approximately the same results by using 20

grams

of sodium sulphite and 10 grams of sodium carbonate. Experiment shows, however, that the developer containing the bisulphite keeps longer and gives slightly less fog than a corresponding developer containing only sodium sulphite which is apparently due to the fact that

the bicarbonate formed acts as an anti-fogging agent

prevent rapid oxidation of the developer. phite in a single solution developer

Sodium bisulphite

is

is

and a buffer to of sodium bisul-

The presence

therefore beneficial.

supplied abroad and to a limited extent in the

t^nited States in the form of a concentrated solution

about 300 grams (10 ounces) of bisulphite to tests

35°

Baume

(Sp. Gr. 1.32 at 6o°F.).

i

The

liter

which contains

(32 ounces) and

solution

is

fairly con-

stant in strength but deteriorates slowly on keeping, forming sulphurous

acid and a crystalline deposit of sodium sulphite

when

stock solution keeps better

The

and sulphate. The volume of water.

diluted with an equal

following table published by L. P. Clerc

^

gives the quantities of

the usual pure alkalis required to neutralize potassium metabisulphite:

TABLE For Neutralizing

100 Parts by Weight of

Sodium

Sodium

Carbonate (Anhyd.)

Carbonate {Cryst.)

Potassium Carbonate

Hydroxide

Potassium Hvdroxide

95 Parts

258 Parts

124 Parts

36 Parts

50^ Parts

Sodium

Potassium Meta-

bisulphite

The

C.

Alkali.

— The common

droxides of sodium, potassium, or

and hyBorax or sodium borate

alkalis are the carbonates

ammonium.

have also been used considerably, particularly tively

low contrast developers.

its

properties

When sodium it

is

carbonate

3

Ltd.,

is

rela-

less alkaline

than carbonate.

A

given on page 119. is

dissolved in water a small proportion of

reacts with the water forming

sodium, bicarbonate: this

compounding

new alkali known as Eastman Kodak Company. It is much

Kodalk was announced by the more alkaline than borax but slightly discussion of

in

In ]\Iarch 1934, a

sodium hydroxide (caustic soda), and though only a small por-

called hydrolysis

"Photography Theory and Practice" by London, 2nd edition, 193".

L. P. Clerc, H.

Greenwood &

Co.,


SUBSTITUTION OF CHEMICALS tion of the carbonate

hydroxide formed

hydrolyzed at any moment.

is

used up

is

so that

we can consider

alkali.

If in the first place

the

same

in

219

As the sodium

development, more carbonate hydrolyzes

that carbonate acts as a reservoir of caustic

a solution of sodium hydroxide was used of

alkalinity as the carbonate, this

The

would soon be used up.

use of carbonate, therefore, enables us to use a small concentration of alkali

and yet keep

it

constant during development.

It is rarely possible, therefore, to substitute caustic alkalis for

ated alkalis such as sodium or potassium carbonate. " sal soda " or

washing soda sold

for

household use

is

carbon-

The commercial usually unsatisfac-

tory as a substitute for sodium carbonate in photographic formulas bs-

cause

it

often contains a large proportion of inactive sodium sulphate and

an excess of water. Regarding the substitution of potassium pard and Anderson

^

have shown

for

sodium carbonate, Shep-

in the case of

an Elon-hydroquinone

contrast developer that no detectable difference could be found

when

the potassium salt was substituted in molecularly equivalent quantities for the

sodium

salt.

A

similar conclusion

graphic work. to

It is

was reached, according

when using process

these authors, by Trivelli

pointed out, however, that these results apply only

one developer and are not necessarily applicable

For practical purposes, the two

salts

may

to other formulas.

be substituted weight for

weight because the difference in their molecular weights

is

quite small.

The addition of about 3^^ by weight of caustic soda to the amount of sodium carbonate is sometimes recommended. Potassium carbonate the disadvantages that

very readily. carbonate

is

On

to

plates for photomicro-

is it

equivalent

more soluble than the sodium salt but it has usually more expensive and absorbs water

is

account of

its

greater solubility, however, potassium

useful in preparing concentrated developers.

For developing motion picture film on a splash on the floor, potassium carbonate

reel is

when

the developer

to be preferred to

may

sodium

carbonate, since by virtue of the deliquescent nature of potassium car-

bonate the splashes of solution remain moist, thus preventing the formation of carbonate dust in the air.

Lumiere and Seyewetz

''

have determined the relative quantities of

various alkalis which give equal photographic effects with different de-

veloping agents as given in the following table: 4 " The Developing Equivalence of Sodium and Potassium Carbonates " by S. E. Sheppard and P. A. Anderson. Brit. J. Phot. 72, 232 (1925). 5 " Contribution to the Study of the Role of Alkalis in Organic Developers " by A. & L. Lumiere and A. Seyewetz. Bull. soc. franc. Phot. 22, 32 (1906).


,

,

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

220

TABLE ^

^

.

,

^

,.

9

,

Potassium

Sodium

.

Sodium ,, Hydroxide

Hydroxide

Hydroquinone

lo

14

96

75

Pyro

10

14

34.2

32.4

Metol

10

14

34-2

28.3

Glycin

10

14

10

14

Developins ,

^

*

,

Agent

Potassium ^^

.

,

.

^

Carbonate

^ l ^ Carbonate

^^^^^^^

^^^^^^^

,

,

122

74.5

Chemically equivalent quantities

26.5

34.5

In arriving at the above results, the developing agents were not com-

pounded

in a developer

formula having a fixed composition.

Since the results of Sheppard and Anderson, and Trivelli did not con-

form with the above, further

tests

were made by the authors and H. D.

Russell as follows: various developing agents were

compounded

in the

following formula: Developing agent Sodium Sulphite (anhydrous)

5.0

37.5

X

Alkali

Potassium Bromide Water to make

Sensitometric tests were ties of the alkali

taken as

made

1.5 1-0 liter

in

each case, using increasing quanti-

compared with 25 grams

standard (pH

= about 9.5).

tain characteristic curves

grams grams grams grams

It

of sodium carbonate (anhyd.) was not always possible to ob-

which were identical

ging tendency with the different alkalis varied.

in

shape because the fog-

For equal fog values, the

relative average quantities of the various alkalis required to

produce

equal densities on the straight line portion of the characteristic curves are given in the following table:


:

SUBSTITUTION OF CHEMICALS Data were developer

(pH

also obtained

with two other alkaHs

221

in

the following

= 9.0)

Elon

2.0 jirams 5.0 ftranis

Hydroquinone

Sodium

Sulphite, 'anhydrous'^

Alkali

Water

to

make

For equal fog values, the

100.0 ftrams

X

i^rams

1.0 liter

relative average quantities of alkalis re-

quired to produce equal densities are given in the following table:


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

222

It

is

therefore possible to give only approximate figures for the equiva-

lence of alkalies unless a particular developer formula

Kodalk

in Developers.

â&#x20AC;&#x201D; Kodalk

is

specified.

more alkaline than borax but slightly less alkaline than carbonate. In relation to sodium carbonate, approximately 2 parts by weight of Kodalk are equivalent to i part by weight of carbonate in all ordinary formulas (except pyro) which do not is

Reference to Figure 64, page 120, will not possible to give one ratio of Kodalk to car-

contain bisulphite or other acids.

show, however, that

it is

bonate which will give developers of equal activities for

all

emulsions and

for all concentrations of these alkalis.

Figure 64 also shows that the activity of Kodalk varies almost

di-

rectly as the concentration of Kodalk, whereas with carbonate the activity increases

very rapidly at low concentrations and In other words,

higher concentrations.

it

is

falls off

rapidly at

dangerous to modify the

activity of low alkaline developers containing carbonate because very

small changes in carbonate content produce large changes in developer

with Kodalk developers to vary the by varying the Kodalk content (see also dis-

It is perfectly feasible

activity.

activity of the developer

cussion on page 119).

Borax, Tribasic Phosphate, Organic Amines and Other AlkaDevelopers. Concurrent with the wide adoption of high speed

â&#x20AC;&#x201D;

lis in

panchromatic emulsions

in recent years, extensive use

has been

made

This chemical

borax as an alkali in developers for these materials.

is

of

a

very mild alkali which gives a developer of low alkalinity and produces negatives of a relatively low degree of contrast.

Furthermore, by adding

suitable quantities of boric acid to a developer containing borax, sible to control the

development rate between rather wide

Tribasic sodium phosphate

graphic developers.

as

This

hydrolyzed

an objectionable scum and

The

hardening fixing bath

in the fixing

alkali therefore is

employed

is

(see

312), although in low concentration

it

in

with alum

salt reacts

bath to form aluminum phosphate which

swell unevenly.

pos-

used sometimes as an alkali in photo-

It is partially

reserve of caustic soda. fixing

is

it is

limits."

water and supplies a in

may

an acid hardening

deposit on the film

bath the gelatin film tends to

most useful only when a non-

Formula F-24, Appendix, page be used with some success

may

with hardening fixing baths.

The amines, which

common 7

"

constituent,

Some

Carlton and

are organic compounds containing nitrogen as a and are related to ammonia, have been suggested

Properties of Fine Grain Developers for Motion Picture Film " by H. C. Trans. Soc. Mot. Pict. Eng. No. 38, 406 (May 1929). I. Crabtree.

J.


SUBSTITUTION OF CHEMICALS for use as alkalis in developers, but these substances

223

have a tendency

to

They have

not, there-

Acetone and formaldehyde are recommended occasionally

for use in

produce dichroic fog and

to dissolve silver halides.

found any general commercial application.

fore,

These substances react with sulphite to liberate caustic soda (see discussion in Chapter VII, page 120). Acetone is a solvent for cel-

developers.

when mixed with water

lulose nitrate, but

out dissolving

it,

should not be used

Formaldehyde der the

name

it

swells the film support with-

and the gelatin emulsion tends

is

in

to

become detached.

It

high concentration in developers for films.

a gas and

" formalin."

is

normally supplied as a

It is also available in solid

37%

solution un-

form as paraform

(paraformaldehyde) prepared by slow evaporation of solutions contain-

When

ing over 30^0 of formaldehyde.

water, a solution for formaldehyde

Ammonia and ammonium

is

this

white solid

is

dissolved in

produced.

carbonate are seldom used in developers on

account of the odor and the fact that they tend to cause dichroic fog.

For a more expanded discussion of the alkalis in development refermade to the articles by Wall and by Seyewetz on this

ence should be subject.*

Desiccated and Crystal Sodas.

â&#x20AC;&#x201D; Sodium carbonate

is

usually sup-

known as the hydrate (NasCOg. loHoO) containing 37% carbonate by weight; plied in three forms: crystals with ten parts of water

tals

decacrys-

with one part of water, called monohydrated carbonate (Na.jCO,.

HoO)

containing

carbonate

85%

(NaXO.)

carbonate; and the dry powder called desiccated containing

98%

carbonate.

The

last

two named

varieties are used chiefly for photographic purposes in the United States

and the first named is used extensively in Europe. Monohydrated carbonate is sometimes stated to have

less

tendency

than desiccated carbonate to cake on mixing with water and to be affected

by atmospheric conditions on

however, that

if

desiccated carbonate

storage. is

stored with only moderate care,

in a closed bin, barrel, bottle, or can, the quantity of

water absorbed

rarely enough to have an appreciable photographic effect, while ing tendency

is

its

no greater than that of monohydrated carbonate.

cause of the water of crystallization present it is

necessary to use

17% more

less

Experiments have shown,

in the

monohydrated

than when the desiccated variety

is

cak-

Be-

variety, is

used.

8 "The Alkalis in Development" by E. J. \\'a.\\. Amcr. Phot. i6, 481 (1922). See also " Practical Equivalence of .\lkalis and Their Substitution in a Given Photographic Developer" by A. Seyewetz. Bull. soc. franc. Phot, ct Cinciuat. 24. 190-93 (Nov. 1937).


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

224

Sodium sulphite is supplied for photographic work in two forms: crys(Na.SOa.yHoO) containing about 50% of sulphite, and desiccated sulphite (Na.SO,) containing about 96 to gyC^ pure sulphite. The desiccated sodium sulphite is much less liable to oxidation by the air than the tals

crystalline variety.

When

substituting the sodas, use the following ratios:

(NaXO^.ioH.O)

3 parts decahydrated carbonate

one of desiccated

to

carbonate. i^ parts monohydrated carbonate (NaoCO;..H^O) to one of desiccated

carbonate. parts of crystalline sulphite (Na.SO.,.7H.O) to one of desiccated

2

sulphite.

Desiccated sulphite

is

now

supplied in the United States in a granular

form which pours easily from a can with

less

dust formation and dissolves

equally as readily in water as the finely powdered salt previously used.

The

Restrainer.

â&#x20AC;&#x201D; Potassium bromide may be replaced by an equal The sodium

weight of sodium bromide. ever,

salt is

and therefore of variable composition.

very deliquescent, how-

Ammonium

not be used in a developer because the alkali liberates this tends to

The

produce dichroic

fog.

addition of an alkali iodide to a developer containing bromide

sometimes recommended (0.01% fog.

Low

to

0.1%)

is

to control the formation of

concentrations of iodide are effective in controlling fog but

higher concentrations (above is

bromide should

ammonia gas and

not practical to replace

all

0.1%)

retard the rate of development.

the bromide with iodide.

This

is

It

because

iodide tends to convert the silver bromide in the emulsion to silver iodide

and materially slows up the less soluble in a fixing

that

it

rate of fixation since silver iodide

bath than

silver

bromide.

Iodide

is

is

much

beneficial in

prevents the formation of abrasion marks and lessens the tendency

for dichroic fog.

Tests on the suitability of a number of organic compounds as antifogging agents in place of potassium bromide have been

made by

Trivelli

and Jensen.^ Of the substances examined, 6-nitrobenziminazole " appeared most promising and undoubtedly further research will reveal other valuable antifogging agents.

Substituting for

/.

Sodium

for Potassium Salts.

photographic purposes, a potassium

salt

â&#x20AC;&#x201D;^As a general

rule,

can be replaced by a sodium

9 " Anti-fogging Agents in Developers " by A. P. H. Trivelli and E. C. Jensen. Frank. Inst. 2io, 287 (1930) ibid. 212, 155 (1931). 10 P. Wulff, U. S. Pat. 1,696,830. ;


SUBSTITUTION OF CHEMICALS

225

weight for weight, the error caused by the difference in molecular

salt

There are many excep-

weight of the two salts being usually negligible.

however, where there

tions,

is

a difference in the physical properties of

the two salts; for example, potassium carbonate and sodium bichromate

absorb moisture rapidly on exposure to a

damp

atmosphere, while so-

dium carbonate and potassium bichromate absorb moisture only very slowly.

important, therefore, that deliquescent salts be stored in

It is

tight containers

and that they be dry when used

for substitution.

SUBSTITUTION IN THE FIXING BATH

— This chemical has been used

Sodium Thiosulphate (Hypo). most exclusively as a

fixing agent for

A

with dry plate and film emulsions, for more than half a century. clear crystalline

al-

photographic purposes, especially fine

form known as prismatic crystal hypo represents a more

rapidly soluble form than the larger pea crystal

hypo which has been

common

fixes sufficiently rapidly

many

use for

years.

It is

cheap and

in

for most types of photographic work. more rapidly and is a satisfactory substitute for sodium salt but it is more expensive. Sulphites and Bisulphites. As stated under the section on "Fixing Solutions," page 151 of Chapter VII, sodium sulphite is usu-

at concentrations of 20 to 40^c

Ammonium

thiosulphate fixes

added

ally

an acid hardening

to

The sodium

of sulphur.

salt is

fixing

bath to prevent the precipitation

used almost exclusively because other

alkaline sulphites are not readily available. tive are the alkali salts of organic acids, of

good example.

Other types of preserva-

which sodium acetate

These substances are known as

" buffer salts "

is

a

because

they reduce the hydrogen ion concentration of the acid employed, be-

low the limits at which sulphur

is

precipitated from

hypo by means

of

acids.

The

acid salts, sodium bisulphite and potassium metabisulphite, are

not suitable for substituting in the usual potassium alum-acetic acid

hardening fixing bath without the addition of acid because the available acidity of these salts

aluminum sulphate

may

chrome alum

Alums. double 11

"

is

insufficient to prevent the precipitation of

sulphite on adding developer to the fixing bath.

Sodium

be used, however, as a substitute for sulphuric acid

bi-

in a

fixing bath.^^

— An

salt of

Some

Soc. Mot. Pict.

alum (as used in photography) is a compound or aluminum sulphate or chromium sulphate with sodium,

Properties of Fixing Baths " by

Eng.No.

3S, 364

(May

1929)-

J. I.

Crabtree and H. A. Hartt.

Trans.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

226

potassium, or

ammonium

sulphate.

The hardening

action

only pro-

is

duced by the aluminum or chromium ion so that equivalent weights of

any sodium, potassium, or ammonium alum or aluminum, or chromium salts, such as aluminum sulphate, etc., should exert the same hardening action.

As a

result of a series of practical tests the following conclusions

have

been drawn: 1. Equal molecular quantities of potassium alum, aluminum sulphate and aluminum chloride exert the same hardening action, two parts by weight of crystalline aluminum sulphate being equivalent to three parts by weight of potassium alum. Commercially pure aluminum sulphate is

satisfactory

if

this

does not contain an excess of iron.

the usual liquid hardener formula with commercial

a slight milky suspension

and then 2.

is

When

aluminum

formed which should be allowed

mixing

sulphate, to settle

filtered off.

There

is

no appreciable difference between sodium, potassium and

ammonium alums

in their

hardening action when substituted weight for

weight in the usual formulas. action occurs, this

is

In practice,

if

any difference

in

hardening

a result of the use of impure alums, in which case,

providing the impurities are harmless, an increased quantity of the alum its content of aluminum sulphate is the same as alum called for by the particular formula. 3. Ammonium chrome alum may also be substituted weight for weight for potassium chrome alum. It has previously been stated that a fixing bath containing ammonium alum has a greater tendency to give dichroic fog than a bath containing potassium or chromium alum, because of the liberation of ammonia when the bath becomes alkaline, but recent tests have shown that this effect is not as serious as had been supposed. Commercial samples of ammonium chrome alum, however, vary considerably in their degree of purity, compared with potassium chrome alum, so that the latter salts are to be preferred. Potassium chrome alum should therefore be used whenever possible, but if ammonium alum has to be used, the fixing bath should be kept in an acid condition to prevent any

should be used so that that in the potassium

possible trouble from dichroic fog. It

is

entirely possible to prepare

chrome alum

fixing baths

which have

alum

fixing baths

properties equally as satisfactory as those of potassium

and which have superior hardening properties. It is usually not possible to substitute potassium alum by chrome alum in a potassium alum formula nor chrome alum by potassium alum in a chrome alum formula unless the

pH

values of the baths are modified.

The

pH

range for sat-


SUBSTITUTION OF CHEMICALS

227

isfactory hardening with a potassium

alum bath is usually from 4.8 to and with chrome alum baths, from 3.0 to 4.0.'Chrome alum in a fixing bath gives the most satisfactory hardening when combined with sulphuric acid whereas potassium alum works best 5.0

with organic acids such as acetic.

be

made

For further

to the discussion of fixing baths

and to the Acids.

literature

in

page 153,

\'1I,

on the subject referred to under Chapter VII.

â&#x20AC;&#x201D; The most commonly used acids are

and sometimes

should

details, reference

under Chapter

lactic acid.

acetic, citric, tartaric,

Strong acids like sulphuric are seldom used

baths containing potassium alum because of the great tendency to

liberate sulphur.

As noted above, however, sulphuric acid

most exclusively when compounding chrome alum acids like the above bear the

bonated alkali

same

any one

Acetic acid

is

strengths, glacial

acid

is

al-

Weaker

they act as a reservoir of acid,

is,

is

available for reaction in

time.

photographic purposes

usually supplied

for

(98%) and 28^ r

acid, so that

equivalent to three and a half volumes of

rule can be given

used

relation to a strong acid as a car-

to a caustic alkali, that

so that only a small proportion of the acid solution at

is

fixing baths.

when

substituting acetic acid

malic and other organic acids.

in

two

one volume of glacial

28% by

The question here

acid.

No

definite

citric acid, tartaric, is

not merely one of

relative acidities, because the degree of hardening of the gelatin pro-

duced by a given quantity of alum

in

combination with equivalent

The

quantities of different acids depends on the particular acid used.

addition of increasing quantities of an acid to an alum solution lowers its

hardening properties and the hardening

falls off at a

greater rate with

increasing additions of citric and tartaric than with acetic.

do not harden gelatin.

As a

rule, therefore,

acetic with citric or other organic acids.

The

and

it is

not advisable to replace

^^

addition of boric acid to a potassium alum fixing bath containing

acetic acid has been

shown

to be beneficial because the

the two acids tends to extend both the sludge life of

Citric

form complex ions with the aluminum ion which

tartaric acids tend to

the bath.^^

life

combination of

and the hardening

In general, 5 grams of boric acid should be added to

12 " Some Properties of Chrome Alum Stop Baths and Fixing Baths " by J. I. Crabtree and H. D. Russell. J. Soc. Mot. Pict. Rug. 14, 483 and 667 (May and June

1930). 13

"

Some

Properties of Fixing Baths " by

14 "

J. I.

Crabtree and H. A. Hartt.

(May 1929). An Improved Potassium Alum Fixing Bath Containing

Soc. Mot. Pict. Russell and

Eng.No.

J. I.

Trans.

3S, 364

Crabtree.

/.

Boric Acid " by H. D.

Soc. Mot. Pict. Eng. 21, 137 (Aug. 1933).


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

228 a

a fixing bath containing hypo, potassium alum, sodium sul-

liter of

and

phite,

acetic acid to produce satisfactory results.

The minimum

concentration of acetic acid in such a fixing bath should be lo cc of glacial acetic acid (37 cc of

28%

acetic) per liter.

Nitre cake or sodium bisulphate acid in a

chrome alum

fixing bath

may

be substituted for the sulphuric

by using

5

grams (73 grains)

of the

bisulphate for each cc (| dram) of sulphuric acid.

â&#x20AC;&#x201D;

Impurities in Developing and Fixing Chemicals. It is beyond the scope of the present chapter to indicate all the possible impurities which may be present in photographic chemicals. For a more detailed account the reader is referred to a paper by H. T. Clarke.^" In this chapter

we

are only concerned with the impurities usually

present in chemicals which are not intentionally added as adulterants.

Impurities

may have

access to photographic chemicals in three ways:

A. During manufacture, B. during storage, C. during mixing and storage of the solution.

A. If chemicals of repute are purchased, the photographer need not

worry about impurities. If the

Elon, hydroquinone or pyro

is

colored, the presence of fogging

agents should be suspected, although some colored samples do not give

any more fog than colorless ones. Many metallic compounds such

as salts of copper

sulphides, etc., exert a powerful fogging action even in

minute quantities, and should be avoided.

A

and

tin,

metallic

when present only

more complete

discus-

sion of the fogging action of metallic salts has been presented in other

papers (see references under Chapter VII, page 121).

Table 8 indicates the nature and

effect of the

more common impurities

present in the chemicals used for developing and fixing baths.

B. For impurities introduced during storage see " Storage of Chemicals,"

fog is

page 192.

The developing agent

C. if

become oxidized and may cause

added after the developing agent (see Chapters VII and

ing of Developers,"

on

will

the water used for mixing contains dissolved air, and

"

Chemical Fog

15

Chcm.

"

if

IX on

and

" Storage of Solutions," respectively,

" in

Amer. Ann. Phot. 33, 20 (1919).

Examination of Organic Developing Agents " by H. T. Clarke.

10, 891 (1918).

stain

and

the sulphite

and

"

Mix-

article

/. Ind.

Eng.


SUBSTITUTIOX OF CHEMICALS

TABLE Nature and Effect of Impurities Chemical Pyro, hydroquinone,

229

12 in Photographic

Chief Impurity Oxidation products and

Chemicals

Effect of Impurities

Chemical fog

adulterants

Adulterants weaken the effect of the developer

Sodium sulphate

Keeping properties of the developer are impaired Iron gives a dirty bluish-red solution with pyro (harmless) Decreases the accelerating power

Potassium bromide

Iron and sodium sulphate Sodium carbonate Potassium chloride

Harmless

Hypo Alum

Sodium sulphite Sodium sulphate and

Diminishes the fixing power Diminishes the hardening action

etc.

Sodium *

sulphite

Sodium

bisulphite

Caustic soda

ammonium

sulphate

Chrome alum

Ammonium

Acetic acid

and sulphuric acid Water

sulphate

Excess of acid tends to cause sulphurization of the fixing bath Deficiency of acid causes milkiness of the acid fixing bath due to the precipitation of alumi-

num *

See discussion, " The Preservative," page ii6.

sulphite


CHAPTER XI STAINS ON NEGATIVES AND PRINTS* A

stain

may

be defined broadly as any deposit, foreign to the photo-

graphic image, which will absorb light and " stain "

word

therefore, capable of pro-

is,

ducing an image during printing, although,

everyday language, the

in

usually associated with something colored.

is

A

photo-

graphic stain can therefore be considered as a deposit on a photographic positive or negative

whose color

is

foreign to that of the photographic im-

This definition would therefore include colored spots, irregular

age.

The purpose of this chapter is to how such stains are produced, how to prevent them, and, whenever possible, how to remove them. Most types of stains result from carelessness, such as overworking a

colored markings, and general stain. explain

developer, using solutions at too high a temperature, lack of agitation,

Almost invariably the cause of and not the manufacturer although the

insufficient fixation or washing, etc.

stains can be traced to the user latter is often

it

blamed unjustly by the former

The diagnosis of the nature of is known at which point in the

the trouble

first

appeared.

appearance of the

stain,

A

a stain

be simplified greatly

if

processing or history of the material

second clue

namely,

for the trouble.

may

its

in the diagnosis is the visual

color, character,

and position on the

material.

Before accepting a job of restoration of a stained negative or print, the photographer should have an understanding in writing that the cus-

tomer assumes the restoration

risk.^

Also, the photographer should not

subject the original to any chemical treatment until he has

tographic copy of first

it.

In some cases, as noted

be made with the aid of suitable

later,

made

to eliminate the

filters

a pho-

an attempt should defect

photographically.

Chemical treatment of photographic materials should never be resorted to until the fundamentals underlying such treatment are thoroughly understood.

Conversely the restoration of a valuable negative or

print should never be entrusted to a novice or less

1

may

be ruined by care-

handling.

* Revised from an article originally written by Amcr. Ann. Photo. 35, 204 (1921).

Co.,

it

"

Laws Which

J.

I.

Crabtree and published

Affect the Photographer " by L. T. Parker.

Qeveland, Ohio, 1930.

in

Abel Publishing


ON NEGATIVES AND PRINTS

STAINS

The Importance

â&#x20AC;&#x201D; The object

Stains.

the gelatin

Thorough Washing

of

any soluble chemicals which might

Preventing

for

washing negatives or prints

in

231

is

remove from

to

later cause fading of the

image or interfere with a subsequent chemical treatment. Since the rate of fading size decreases,

it is

-

of

an image usually increases as the grain

obvious that negatives on fine grained emulsions

re-

more thorough washing than those on coarse grained ones. The average negative can be considered to be washed adequately if it is

quire

treated for 30 minutes, in a tray or tank into which water

a rate sufficient to replace the water in the vessel hour.

5 or 6

is

running at

times each half

Fine grained negatives should preferably be washed at least one

hour under the above conditions. Prints need to be washed longer than negatives, because the paper

Usually, a print should be wached

base tends to retain the chemicals. for at least

one hour

in a vessel in

which the water

the rate of 10 to 12 times per hour.

water

The time

which a stream of water

in the vessel into

found easily by adding to the vessel a

sufficient

is

being replaced at

required to replace the is

flowing

quantity of

may

1%

sium permanganate solution (10 grains potassium permanganate ounces water)

(i

gram

in

The

in

2^

100 cc of water) or red ink to color the water

appreciably, and noting the time required for the water to less.

be

potas-

become

color-

flow of water should then be adjusted so that the vessel

empties at least 10 to 12 times each hour.

For greatest permanence, after in

fixing, place the prints for 5

a fresh fixing bath and then wash for

2

minutes

hours under the foregoing

conditions.

Classification of Stains.

â&#x20AC;&#x201D; For purposes

of reference, stains

have

and the remarks apply

to all

photographic sensitive materials including films, plates, lantern

slides,

been

classified according to their color

paper prints and motion picture gelatin emulsion

All of these are coated with a

which after developing and

fixing consists of a layer

embedded an image of silver, or one of its comIn what follows the word " film " is used synonymously with

of gelatin in

pounds.

film.

which

is

such a gelatin silver image.

General gray stain or fog has been treated in a previous chapter (see

page 139).

In this chapter

we

will consider

a stain as a fairly large

deposit whose color differs from that of the image and which 2 "

A

Method of Testing

ture Films " by

1930).

J. I.

for the Presence of

Crabtree and

J.

F. Ross.

/.

Sodium Thiosulfate

in

may

be

Motion Pic-

Soc. Mot. Pict. Eng. 14, 419 (Apr.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

232

" local "

(when

it is

not uniform) or " general," in which case

form and of even density over the entire

it is

uni-

film.

Several specific classes of markings or stains as

may

be caused by

moisture,^ airbells,^ static/' the presence of developer fog from sulphide/

and

oils/ are discussed in detail elsewhere.

WHITE STAINS A

White Powdery Scum,

removed by washing, it washing of the film. hypo crystals and is due If it is insoluble in water, and therefore not removed by washing but is dissolved by sodium carbonate or acetic acid, it consists of aluminum I.

consists of

sulphite.

a

is

is

to insufficient

The

10% sodium

ing

If this

by dipping

solubility test can easily be

carbonate solution on in water.

If

made by

placing a drop of

the edge of the film

on drying the

film

is

clear,

most probably aluminum sulphite providing an alum

and then wash-

then the deposit fixing bath

was

used.

The

acid fixing bath most

commonly used

consists of a mixture of

alum, acetic acid, sodium sulphite, and hypo, or

in other

words, a mix-

hypo and aluminum sulphite dissolved in acetic acid. If sodium carbonate is added to this, the acid is neutralized forming sodium acetate, and as soon as the quantity of acid in the bath falls below a certain critical value the aluminum sulphite comes out of the solution, turning the bath milky and deposits as a white sludge which settles on the surface of the film, and is not removed in the wash water.* Since developer is carried over to the fixing bath by the film, only a ture of

definite is

number

of films or prints can be fixed before the critical point

reached and the precipitation of the sludge commences.

tures

At tempera-

around 65°F. (i8°C.) usually a further quantity of acid

added

to the fixing

bath to compensate

may

be

for this developer carried over,

3 " Moisture Markings on Motion Picture Film " by J. I. Crabtree and G. E. Matthews. Trans. Soc. Mot. Pict. Eng. No. 17, 29 (1923). Revised 192S. 4 " Rack Marks and Airbell Markings on Motion Picture Film " by J. I. Crabtree and C. E. Ives. Trans. Soc. Mot. Pict. Eng. No. 24, 95 (19-25). 5 " Static Markings on Motion Picture Film " by J. I. Crabtree and C. E. Ives.

Trans. Soc. Mot. Pict. Eng. No.. 21, 67 (1925). 6 " Sulphide Fog by Bacteria in Motion Picture Developers " by and J. I. Crabtree. Trans. Soc. Mot. Pict. Eng. No. 19, 28 (1924)7

" Oil Spots

on Motion Picture Film

Trans. Soc. Mot. Pict. Eng. No. 32, 728 * The addition of boric acid (about

"

J.

L.

I.

Dundon Crabtree.

1927)1%) greatly minimizes the sludging tendency (

of a potassium alum-acetic acid fixing bath alkalinity.

by G. E. Matthews and

M.

when used with developers

of average


STAINS though

in

ON NEGATIVES AND PRINTS

warm weather

there

233

danger of sulphurization (see page

is

185).

In order to prolong the tion of a.

as

aluminum

of the fixing bath

life

sulphite

it

and prevent the forma-

advisable to:

is

Rinse the film between the developing and fixing so as to remove developer as possible.

much b.

Avoid the use of a developer containing an excessive quantity of

alkali. c.

Use an acid

rinse bath

between the developer and

Stop

fixing bath.

baths should always be used with discretion, however, otherwise an excess of acid

is

carried over to the fixing bath which in turn causes sul-

phurization.

A

suitable rinse bath for negative materials consists of a

tion of

For

sodium bisulphite or a

3%

solution of potassium

2.5%

solu-

chrome alum.

1.25% solution of glacial acetic acid is satisfactory. aluminum sulphite sludge still appears after observing the above precautions, then either the acid hardener was not mixed correctly (probably too little acid was added) or the acid used was not up to strength, or too much sulphite was used. Precipitation or " scumming " may take place on the print or negative with a very alkaline developer even when the fixing bath is clear, prints, a

If the

if

no stop bath

is

used.

This

is

due

to the fact that precipitation occurs

before the developer has time to diffuse of the film

when

it is first

moving the excess

immersed

away from

in the fixing

the film.

bath

Agitation

will assist in re-

of developer from the surface of the film

and

will

reduce the tendency for a precipitate of aluminum sulphite to form.

The

following fixing bath formula was devised in 1934 and has the

valuable property that

normal useful

it

has a very low sludging tendency during

its

The hardening properties are also maintained durThe formula is satisfactory for use with amateur and

life.

ing this period.

professional negative materials.

Acid Hardening Fixing Bath Avoirdupois

Water (about

Hypo Sodium

125째 F.) (52째 C.)

.

.

.

ounces ounces "jounce ounce I

16 11

Sulphite, desiccated

Kodalk Acetic .\cid,

28%

Potassium Alum Cold water to make

ounces ounce ounces

214 fluid ?i

32

[F-10] Metric 500.0 cc 330.0 (>ranis 7.5 30.0 70.0 22.5

ftratns

$>rams cc

j^rams

1.0 liter

Dissolve the hypo in one-half the total volume of water and then add the remaining chemicals in the order given after dissolving in a small volume of water (about I25째F.) (52째C.). Dilute with water to the required volume.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

234

Removal of Aluminum Sulphite aluminum

bility of

dium carbonate, the scum few minutes oughly.

in a

wash the

5%

5

removed by bathing the film for a sodium carbonate and washing thor-

is

above 65°F. (i8°C.),

minutes

for 2 or 3

about

film

view of the solu-

easily

is

solution of

temperature

If the

harden the film

— In

Stain.

sulphite in sodium hydroxide (caustic soda) or so-

it

is

advisable to

and then

in the following solution,

minutes before any subsequent chemical treat-

ment:

Formalin Hardener

[SH-1]

Formalin (37% Formaldehyde solution;

Sodium Carbonate, desiccated Water 2.

to

make

Yellowish-White Opalescence.

ally visible only

made on

moved by bleaching and redeveloping sists of finely

more a. is

— This

1 .0

liter

particular stain

is

usu-

The

opal glass or celluloid.

(see

page 241).

divided or colloidal sulphur and

may

The

is

de-

not re-

stain con-

be due to one or

of the following causes:

Too much

added

tate,

10.0 cc 5.0 grams

and sodium carbonate, and

insoluble in water, acids,

is

Metric

2}2 drams 73 grains 32 ounces

on negatives or transparencies, and gives the negative

the appearance of having been posit

Avoirdupois

acid or too

to hypo, sulphur

but this

may

little is

sulphite in the fixing bath.

If,

and

therefore, the proportions of acid

phite are not correct in the fixing bath, or is

acid

be prevented by the presence of sodium sulphite

which dissolves sulphur. an excess of acid

When

thrown down as a yellowish white precipi-

if

impure sulphite

added when preparing the

sul-

used or

is

fixing bath, sulphur

is

gradually precipitated, and this precipitation takes place likewise in the

The time which elapses before sulphur is precipitated is known as the " sulphurization " life. b. The fixing bath is too warm. The sulphurization life of a correctly compounded fixing bath is relatively short at temperatures above 85 °F. The only remedy is to renew the bath as soon as sulphuriza29.5°C.) gelatin film.

.

(

tion begins. c.

The

will often

use of a plain potassium alum bath either before or after fixing

cause sulphurization, because alum behaves like an acid to-

wards hypo. free

If the

alum bath must be used, the

film should be

washed

from hypo before treatment.

Removal ing for

2

of Sulphur Stain.

First super-harden the film

by bath-

or 3 minutes in the alkaline solution of formalin given above

and washing thoroughly before treatment.

Then immerse

the film


ON NEGATIVES AND PRINTS

STAINS in a

warm io%

mately ioo° 3.

to

235

solution of sodium sulphite at a temperature of approxi-

i20°F. (38° to 49°C.) and wash thoroughly.

Silvery-White Opalescence.

— This

peculiar stain

is

formed

when drying negatives

or transparencies by means of denatured or wood

alcohol and especially

if

phenomenon

the drying

is

This

hastened by means of heat.

has been attributed to various causes, including the use of

impure alcohol, or alcohol containing

resins, insufficient fixing, or

wash-

ing of the film, the presence of calcium salts in the wash water, etc.

may

Although these factors

influence the

amount

duced, they are not the determining factors, since

of opalescence pro-

it is

possible to obtain

severe opalescence by immersing a film of plain gelatin in pure grain

The amount more rapid the drying and the

alcohol and drying at a temperature of 95°F. (35°C.). of opalescence produced

greater, the

is

higher the temperature of drying, but is

insufficiently

and washed

fixed

it

if

rarely occurs even

drying

if

the film

conducted at 70° F.

is

(2I°C.).

The opalescence

is

apparently due to precipitation of the gelatin by

the alcohol to a dehydrated modification which

more readily precipitated than

The

precipitation

is

warm

ing alcohol to a solution of gelatin in

also

produced by add-

water.

Hard

gelatin

is

soft gelatin.

the film is immersed in concenhypo or sodium sulphite. When a strong solution of hypo containing an excess of

is

produced

also

if

trated solutions of certain salts such as fixing a negative in

acid hardener, the fixed film often appears milky, especially in

weather, though the milkiness disappears in the wash water precipitated gelatin returns to the hydrated modification.

escence will often appear solution of

when removing sulphur

sodium sulphite

Removal of Opalescence.

— Immersion

in

fixed,

washed, immersed

in

volumes of water, wiped

if

warm

on washing.

water and drying at

normal temperatures removes the opalescence completely. ing with alcohol, opalescence rarely occurs

the

This opal-

stains with a

(see above) but disappears

warm

when

the film

is

When

dry-

thoroughly

a mixture of 90 volumes of alcohol and 10

off carefully,

and then dried by a fan

at a

temperature not exceeding 7o°F. (21'^C.).

To Summarize.

It

is,

of course, possible for

of white stains to be present on the stain, therefore, the film

should

first

same

film.

two or more

varieties

To remove an unknown

of all be fixed in plain hypo, washed,

and bathed in a 10% solution of sodium carbonate and washed to remove any aluminum sulphite. If a stain still persists this is due to sulphur, and is removed by first hardening the film for two or three minutes,


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

236

formalin hardener (page 234), immersing in a 10% solution of at 100° to i20°F. (38° to 49°C.) and washing.

in the

sodium sulphite 4.

Yellowish-White Stain.

— This

particular stain occurs princi-

pally on old D. O. P. prints, the effect being a faded appearance chiefly

where there

in the highlights is

is

least silver,

and the

to the conversion of the silver

image

image

color of the

This stain which develops with age

usually yellowish white.

is

due

to a yellowish-white modification

That such a modification does exist can be shown by immersing a piece of well washed and unexposed printing-out paper, the

of silver sulphide.

emulsion of which consists essentially of silver chloride, in a

sodium sulphide.

tion of

2%

solu-

Prolonged action of the bath produces a yel-

lowish-white image whose color resembles that of the stain in question.

The formation

of the silver sulphide

may

be due either to internal or

Internal agents are usually thiosulphates left in the

external causes.

and washing as explained above. Owing atmosphere and moisture these thiosulphates are

print from insufficient fixing to the action of the

oxidized,

and

at the

same time the

silver

image of the print

is

converted

to silver sulphide. If the print is fixed in a

sulphur, caused by too

sulphurized bath which

much

is

slowly depositing

acid in the fixing bath, or

by the use

of a

too strongly acid rinse bath (see sulphur stains, page 234), the sulphur is left

in the print

image

to

form

even after washing, and

silver sulphide.

image of a print

is

The

this

combines with the

relative ease with

which the

sulphurized as compared with a negative image

silver

silver is

due

to the fineness of grain of the print image.

Some of the factors which determine the degree of fading are: 1. The quantity of hypo or of silver thiosulphate left in the image. The coarser the grain, the less readily 2. The grain size of the image. is it

attacked and, therefore, the image has

less

tendency to fade.

At room temperature 3. The temperature and humidity of storage. iio°F. while at 6 months, (43 °C.) the same an image may fade within image

may

fade overnight.

External agents are sulphurous gases in the air such as hydrogen sulphide, while the hypo, which

may

be decomposed and

may

act in a

be present in the mount of a print

manner

similar to that of the thiosul-

phates left in the print as outlined above.

Fading

may

be minimized by the following procedures:

images are fixed thoroughly with agitation in a fresh acid fixing bath which is perfectly clear and not depositing sulphur, and are then washed thoroughly, fading and therefore yellowish white stains may I.

If


STAINS

ON NEGATIVES AND PRINTS

largely be prevented. i-i

minimum 2.

Developing-out papers require washing from

an adequate stream of pure water

to 2 hours in

propensity to

in

order to insure a

fade.**

Bleach the fixed and washed image

in the

chloride-sulphuric acid bath and redevelop and

page 241.

237

This treatment destroys any traces of

permanganate-sodium wash as explained on harmful sulphur com-

pounds, probably converting them to inert sulphates. 3.

Convert the

silver

image

to silver sulphide

by sulphide toning

in

the usual manner. 4.

Treat the washed print

in a s'y(

solution of sodium carbonate at

This converts any

a temperature of iio°F. (43°C.) and then wash.

compound

residual sulphur

sodium sulphide which washes out more

to

readily.

Most pastes are hygroscopic 5. Avoid the use of paste adhesives. and the presence of moisture tends to accelerate fading. Ordinary starch paste or photo paste have a

minimum tendency

extreme permanency, use only dry mounting

to cause fading but, for

tissue.

Also,

when

storing

negatives in paper envelopes, the pasted seam should be along the edge

and not

in contact

of Yellowish-White Stain.

or rather the restoration of the image to

simple matter but

The image

apt to occur shellac adhe-

â&#x20AC;&#x201D; The removal

of the stains,

with the image.

sive should preferably be used.

Removal

is

A

middle of the envelopes because fading

in the

where the pasted part comes

may

its

original color,

is

often a very

also prove to be a complicated procedure.

of the stained print

may

consist of several substances in-

cluding unchanged silver, silver sulphide, possibly oxidation and silver

and possibly

stain (see page 238), undissolved thiosulphate, tohalides.

moval print,

Usually bleaching and redeveloping as

of oxidation stain

though

silver

pho-

in the case of the re-

(see page 241) will thoroughly restore the

in a severe case

proceed as follows:

from the print by rubbing with artgum or by dabbing with a piece of stiff dough made from wheat flour. Grease marks can be removed with benzol, or gasoline, and the print finally rubbed over

Remove

all dirt

with alcohol.

If the print

is

mounted, detach

it

from the mount by

first

thoroughly soaking in water, then place face downward on a sheet of smooth paper and tear the mount away from the print. This is important, otherwise

8

"

A

Method

if

is

made

to pull the print

of Testing for the Presence of Ross. J. I. Crabtree and J. F.

Picture Films" by

(Apr. 1930).

an attempt

away from

Sodium Thiosulphate /.

in

the

Motion

Soc. Mot. Pict. Eng. 14, 419


238

PHOTOGRAPHIC CHE:MICALS AND SOLUTIONS

mount

it

be torn.

will inevitably

dry mounted, heat

If the print is

in a

press and strip.

Now

the print thoroughly in plain

fix

hypo

to

remove any undis-

solved silver halide, wash thoroughly, and then harden

two or three minutes wash.

If

by bathing

should be removed in a

2%

solution of potassium cyanide, removing the

print as soon as the image begins to be attacked (cyanide

poison and should be used with great care).

The

for

an alkaline formalin solution (page 234) and the highlights are stained this is due to silver stain which in

print should

now be bleached

in the

is

a deadly

Then wash thoroughly.

permanganate bath and

re-

developed as recommended for the removal of developer stain (see page

The permanganate bath converts

241).

the image consisting of silver

sulphide to silver chloride and this develops to a black silver image in the redevelopment.

The above treatment out papers.

is

satisfactory only for images on developing-

Gold toned images on printing-out papers are ruined by

the treatment since the gold image

is

converted to soluble gold chloride

by the bleaching bath. Faded images on printing-out paper can usually be improved by bleaching in a saturated solution of mercuric chloride, washing very thoroughly, and then redeveloping

in the

developer given on page 242.

YELLOW STAINS Yellow stains II. silver stain, I.

may

and

be of three kinds:

I.

developer or oxidation stain,

III. silver sulphide stain.

Developer or Oxidation Stain.

â&#x20AC;&#x201D; This

stain

is

caused by oxi-

dation products of the developer which are transparent like a yellow dye.

The

stain

may

be either

" local

"'

or " general."

Owing

to the fact

that printing papers are usually sensitive chiefly to blue light which

is

strongly absorbed by a yellow color, the stain acts as though a yellow filter

were placed over the negative.

Local yellow stain, therefore,

causes the image on the print to be weaker in those spots where the stain

is

present.

General yellow stain which covers the entire film just as though the film

had been uniformly dyed yellow has no harmful

effect other

than

to increase the printing exposure.

A. Local Developer Stain. pyro, hydroquinone,

oxygen especially

etc.,

â&#x20AC;&#x201D;

All developing agents, such as Elon,

have the property of readily combining with

in alkaline solution to

form oxidation products which

are often colored yellow or dark brown, and which have the property


ON NEGATIVES AND PRINTS

STAINS

of staining gelatin just like

a developer

is

exposed

and the developer turns yellow more or

to the air oxidation takes place less

When

an acid dye.

239

rapidly according to the temperature, the nature of the developer

and the amount of surface of developer exposed.

The

oxidation products, however, can in turn be reduced back again

by substances

to a colorless condition

so that

if

sodium sulphite or bisulphite

like

the developer contains an excess of sulphite, the rate of for-

mation of the oxidation stain

slow and usually proportional to the

is

quantity of sulphite or preservative present.

Apart from is

development the developing agent

aerial oxidation, during

being used up by virtue of

silver salt to metallic silver

reducing action in changing the exposed

its

and

in

so doing

is

it

oxidized

itself,

the

product formed probably being identical with that produced by aerial oxidation.

The amount

of oxidation product

formed

in this

way

is,

of

course, proportional to the quantity of silver developed, so that the pho-

tographic image

on a

silver

is

of a duplex nature consisting of a stain superimposed

That such an image

image.

immersing a pyro developed negative

moves the black

exists

in

image, leaving a yellow image which

silver

of the oxidation product of development.

image

is

The

is

utility of this stained

a stain image, though with developers like

glycin whose oxidation product the developer, the stain image

is

is

readily decolorized

by the sulphite

tanning gelatin, so

very feeble.*

much

that

so,

if

a negative developed with, say,

placed in hot water, the gelatin in the clear and

is

unhardened portions dissolves away leaving a relief image. Local irregular shaped stains are caused by local oxidation developer which

may

of the

be due to:

Careless handling of the film by incomplete immersion in the de-

veloper or fixing bath. films or prints in

responding

A

slight curl of the film or print, or too

many

some part of the surface exposed take place and a yellow patch will appear cor-

one tray,

to the air, oxidation will

air.

in

oxidation product, apart from being colored, has the property of

caustic hydroquinone

I.

re-

composed

explained below.

Most developers form such

The

can readily be seen by

Farmer's reducer which

will leave

in size to that of the

In motion picture work,

if

submerged a yellow oxidation film at regular intervals.

To

portion of the emulsion exposed to the

the top of the film rack stain

is

is

not thoroughly

produced which appears on the

prevent such stains

it is

obviously neces-

* In the presence of sodium sulphite, the oxidation products of hydro<|uinone probably consist of colorless hydroquinone mono- and di-sulphonates (see discussion

under Chapter VII, page 133).


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

240

sary to immerse the films or prints completely in the developer or fixing bath. 2.

An

Since a developer oxidizes more rapidly

alkaline fixing bath.

in alkaline

than in neutral or acid solution, as the acid

in the fixing

bath

becomes neutralized by the developer carried over by the film, this developer oxidizes more and more rapidly and stains the fixing or rinse bath. When the fixing bath froths readily, it is probably alkaline and should be thrown away, though in some cases, acidity

by adding further quantities always important

It is

to

move

it is

prints or films around in the fixing

bath so that the alkaline developer in the print the acid in the fixing bath.

possible to renew the

of acid at intervals.

is

neutralized at once

by

simply thrown into

If the prints or films are

the bath and allowed to remain at rest, the developer clings to the film and the acid in the bath is not strong enough to neutralize it completely, so that the developer oxidizes and stains the film locally wherever there is an excess of developer, and especially if the film is locally exposed to the

air.

An

acid rinse bath between developing and fixing

in the developer in the film before

it

an almost certain

is

This neutralizes the alkali

cure for local developer stain (see page 233).

reaches the fixing bath, thus re-

ducing the tendency for further oxidation.

B. General Developer Stain. entire surface of the film 1.

and

is

â&#x20AC;&#x201D; This

exists

uniformly over the

caused by:

Old or discolored developer or a developer containing an insuffiimpure sulphite. General pyro stain is the

cient quantity of sulphite or

most common on negatives. In the case of prints, general yellow stain is

forced in a

warm

rinsed too long after developing

not agitated 2.

The

when

a.

in

produced

first

immersed

and before

fixing, or

of Developer or Oxidation Stain.

two ways:

a.

photographically, and

Local yellow stains

imposing a deep yellow

may filter

if

development

if

the prints are

if

the prints are

in the fixing bath.

use of a plain alkaline fixing bath.

Removal moved

is

developer, or in a dirty tray, or

b.

â&#x20AC;&#x201D; This

can be

re-

chemically.

be removed photographically by superover the negative and making a master

positive from this in a printing frame on a panchromatic film or plate just as w'hen

making

a paper print

from a negative.

Wratten G, and a suitable emulsion chromatic film or the Wratten Panchromatic plate. filter is

the

Panchromatic

film

is

is

sensitive to light transmitted

A

suitable yellow

Commercial Pan-

by the

G

filter

and


ON NEGATIVES AND PRINTS

STAINS in

turn the

G

filter is

a deeper yellow than most yellow stains, which are,

therefore, eliminated provided the stain

the stain contains any gray deposit the

nate

241

completely transparent.

is

filter

If

will obviously not elimi-

it.

An

method is to illuminate the negative by transmitted when copying or making an enlarged, reduced, or full sized and use a sheet of the filter film or a filter mounted between

alternative

light as

positive,

In this case a piece of

glass over the lens.

the diameter of the lens

Caution:

mount

filter

only slightly larger than

required.

Filter film consists of sheets of

mounted between

dyed gelatin and when not

be kept dry and free from finger marks. made it is a simple matter to make a dupli-

glass should

After the master positive cate negative on, say, in the usual

is

is

Eastman Commercial

film or

an Eastman 33 plate

way.

When making

master positives or duplicate negatives, care should be

taken to give sufficient exposure so as to produce clearest parts of the image.

A

full detail in

even the

good duplicate negative has no clear

shadows.

remove almost any colored

It is possible to

manner by a

print in a similar stain in question It is

muddy

as

if it

simply necessary to choose a

through the

be used

which blue

not

is

filter,

is

filter will

filter

provided the

such that on viewing the stain

and so on, taking care

sensitive to all colors.

from a negative or

filters,

were mixed with a black medium.

the stain becomes invisible.

for a red stain

stain

suitable choice of

Thus, a red to use

filter

should

panchromatic

film,

In the case of a blue black ink stain a

cut out only the blue.

It

better to

is

remove such

stains

by chemical means. b.

the oxidation product of the developer

If

(oxidation stain)

treated with an acid solution of potassium permanganate, further to a colorless substance which

is

it

is

is

oxidized

soluble in water. Such an acid

solution would dissolve the silver image also, but

if

sodium chloride

is

added, the bath converts the silver image to one of silver chloride while the stain is being oxidized. If the silver chloride image is now exposed to light

image

is

and developed in a non-staining developer, the restored free from stain.

To remove First

developer stain, therefore, proceed as follows:

harden the film by bathing

wise the gelatin

Then

is

apt to

for

2

or 3 minutes in an alka-

page 234) and wash for 5 minutes, othersoften and frill during the subsequent treat-

line solution of formalin (see

ment.

original silver

bleach in the following:


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

242

Stain Remover

[S-6]

Metric

Avoirdupois

Stock Solution A Potassium Permanganate

Water

to

make

Stock Solution B Sodium Chloride (table salt) Sulphuric Acid, C. P. (concentrated)

A 5% but as

>^

32

A

parts of

75.0 grams 16.0 cc

ounce ounces

1.0 liter

and B.

solution of hydrochloric acid can be used instead of Solution B;

it is

often of uncertain strength,

A

use

its

is

not recommended.

if

kept separately, but not when mixed,

for this reason the bleaching

bath should be prepared as required.

Solutions

and

ounces

Hi ounces

Water to make

Use equal

5.3 grams 1.0 liter

grains

75 32

When

and B keep well

preparing Solution A,

make

sure that no particles of undiswill cause spots

solved potassium permanganate remain because they

and blemishes

in the negative.

The bleaching should be complete there

usually

is

manganese

oxide,

the image.

It is

then placing in a

left

a general brown

and especially best to remove

1%

about

in

or 4 minutes

3

in those parts previously this stain

solution of

when

stain all over the film due to

sodium

by

first

occupied by

rinsing in water

Wash

bisulphite.

and

for 3 or 4

minutes, and expose to a strong light {sunlight or arc light) until the

white image turns purple.

such as Nepera solution

Then develop

(dil.

in a non-staining developer,

1:2) or the following developer:

Diaminophenol Developer

[D-51]

Metric

Avoirdupois

Water (about

Sodium

ounces

24 350

125° F.) (52° C.)

Sulphite, desiccated

grains

H

Diaminophenol Hydrochloride (Amidol) Cold

When

vv'ater

to

make

removing stains by

32

this

750.0 cc 24.0 grams 7.5 grams 1.0 liter

ounce ounces

method, markings caused by drying a

negative without removing the drops of water (water markings), are usually removed also unless the markings are of long standing.^

— Although

most photographic stains are objectionable, a developer stain image, which is formed in position along with the silver image during development as explained

Usefulness o£ Developer Stain.

on page 239

is

often of great value because

it is

capable of producing a

same way that a print is produced by a silver image. Photographic papers are usually sensitive to blue light only, which is strongly absorbed by a yellow stain. The stain, therefore, behaves photoprint just in the

graphically like a black image.

Figures 93 A and 93 B illustrate this

9 " Moisture Markings on Motion Picture Film " by J. Matthews. Trans. Soc. Mot. Pict. Eng. No. 17, 29 (1923)-

Crabtree and G. E. Revised 1928.

I.


STAINS Figure

point.

93A

ON NEGATIVES AND PRINTS

a reproduction of a print

is

This negative was then phiced

tive.

silver

was removed, leaving

in

a yellow stain

243

from a pyro-stained nega-

Farmer's reducer until

all

the

image (see Figure 93B).

A. Print from negative having both

silver

and

stain images.

B. Print Fig. 93

from

ne^'ative

â&#x20AC;&#x201D; Effect

having only a stain image.

of pyro stain image on effective

printing contrast.

Of course, pyro

is

not the only developer which will give a stain image.

Developers such as hydroquinone give tion products,

and these can be

warm brown and reddish oxidawarm tones by

utilized in obtaining

direct development.

The

printing value of a stain image explains

why an

apparently weak

looking pyro negative will give good prints on a soft printing paper.

This is

is

because the stain which appears transparent and weak to the eye

really

opaque photographically.

So far as

it

has been possible to determine, a pyro stain image merely

intensifies the black silver

image and does not otherwise

alter the photo-

graphic quality, so that usually the same result in printing can be obtained

by prolonging development

be attained by intensification.

of the negative.

This result can also


:

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

244

The question

is

often asked, therefore,

if it is

better to develop for a

longer time in a non-staining developer like Elon-hydroquinone or for

a shorter time in a staining pyro developer.

If it

necessary always to

is

duplicate results as in the case of developing motion picture film in a

deep tank, a non-staining developer conditions

it is

is

desirable because under these

impossible to duplicate results with a staining developer

as explained below.

Control of Developer Stain. It is practically impossible to obimage which is free from general stain and vice versa. The proportion of general stain to image stain depends on the following tain a stain

factors a.

The quantity

of sulphite or preservative in the developer.

greater the quantity of sulphite present, the less

and vice

is

The

the stain produced

versa.

If the

developer

is

old, it rapidly

produces general stain with

little

becomes highly colored and then

or no silver or stain image, because the

developer has been converted largely to oxidation products which will not develop an image. b.

The time

of rinsing between developing

and

fixing.

A

long rinse

permits further oxidation of the developer by the oxygen dissolved in the

wash water and

c.

The nature

this

produces general stain. Since sulphite or bisulphite bleaches

of the fixing bath.

out stain and prevents oxidation of the developer, an acid fixing bath, therefore, destroys both general stain

order to produce the

maximum

and the stain image.

Hence,

in

quantity of stain image, use a fresh

developer containing low sulphite, rinse quickly between developing and fixing,

and

The

fix in

a large volume of fresh hypo.

following pyro formula

when used

image with a minimum of general

good stain

Pyro-Stain Developer

[SD-1] Water (about

Sodium

Avoirdupois 16 ounces

125° F.) (52° C.)

Sulphite, desiccated

20 40 75 32

Pyro

Sodium Carbonate,

desiccated

Water to make

Develop fix in

fresh will give a

stain.

for 6

minutes at 65 °F. (i8°C.)

Metric 500.0 cc

grams grams grams

grains grains grains

1.4 2.8 5.3

ounces

1.0 liter

in a shallow tray, rinse

and

a plain hypo bath.

The above

reasons explain

on a practical scale such as

why

it is

in small

impossible to produce pyro stain

amateur tanks or

in

deep tanks.

As

the developer becomes older the proportion of oxidation stain to stain

image changes, which

in turn

changes the quality of the negative.


STAINS

ON NEGATIVES AND PRINTS

If a negative is stained too strongly, the stain

removing

it

entirely

by bleaching

in a

may

245

be reduced by

first

permanganate-chloride bath (page

242) and then redeveloping in a mildly staining pyro developer (Formula D-i, page 281). This procedure usually gives more general stain,

however,

in

proportion to the stain image than

had been developed with the staining developer

Yellow Silver Stain.

II.

compounds

â&#x20AC;&#x201D; Another form

observation, though

it is

one or more of the following causes:

is

it

is

more

of a dirty

use of an old and exhausted fixing bath containing an excess

of silver in solution so that

if

the film

not sufficiently washed, some

is

This compound

colorless,

but

gradually changed to yellow silver sulphide on exposure to the

air.

of the silver salt remains after drying. is

to

It

can be either local or general and

may be due

to

due

usually less transparent and

Like oxidation stain

The

is

and washing.

from oxidation stain by ordinary

yellow color.

a.

the original emulsion

of yellow stain

of silver left in the film after fixing

to distinguish silver stain

difficult

if

in the first place.

To prevent such

stains, therefore,

acid fixing solution b.

and

to

Insufficient agitation

it

is

is

important to use only a fresh

wash thoroughly. on

first

immersing the films

In the absence of agitation, the developer

in the fixing bath.

in contact

with the film

re-

duces the silver halide dissolved out by the hypo back again to yellow metallic silver. The propensity for this stain to form is greatest with

very alkaline developers and with old fixing baths which have become neutral or alkaline. c.

A common

cause of silver stain when handling

development and fixation

of

two lengths of

roll

film placed

film

back

is

the

to back.

this may save space, it is false economy, because it is impossiwash the backs of the films which stick together. The result is that hypo containing silver is left in the gelatin backing which turns to silver sulphide on exposure to the air, so that while the emulsion side

Although ble to

of the film

is

clear the gelatin backing

is

stained.

In the case of films with anti-halation backings this procedure will obviously cause irregular stains.

When

the emulsion side of one film adheres to either the emulsion side

or back of another, the trapped developer reduces the dissolved silver

compounds

as explained in paragraph b, above,

silver stain.

Removal moved

of Yellow Silver Stain.

â&#x20AC;&#x201D;

and produces a

local

Silver stain cannot be re-

by bleaching and redeveloping as in the case of oxidation stain,


5

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

246

because this has simply the effect of converting the yellow silver sulphide

and then

to silver chloride

to silver so that the yellow stain is

changed

to a black stain of metallic silver.

There

no

is

way

of

always completely removing

silver stain,

though

the following methods are frequently successful:

After thoroughly washing to remove any hypo, bathe the film in a

a.

1%

solution of potassium cyanide {cyanide

and a

a deadly poison

is

solution in water emits fumes of poisonous hydrocyanic acid so that

The cyanide

should be used only in a well ventilated room).

it

will dis-

and some silver sulphide, though in image so that the film should be removed from the bath and thoroughly washed as soon as any signs of reduction

solve

any

time

it

silver thiosulphate present

dissolves the silver

of the image appear.

weak

In the case of an old negative, treatment with a

solution of

acid permanganate, washing, and then immersing in the cyanide will

often remove obstinate stains. b.

G

Copying the negative or print through a

paragraph

a.

page 240

will reduce,

filter

as described under

but not always completely remove,

silver stain. c.

The

stained gelatin backing

may

be removed from a non-curling

down onto

negative film as follows: squeegee the negative emulsion side

a sheet of Kodaloid previously coated with rubber cement diluted with

benzene, containing

5%

amyl

acetate,

and allow

it

Then

to dry.

place

the film and backing in a tray containing 5% sulphuric acid maintained o ° F. 8° The backing will dissolve in about 1 00 ° to 1 1 to 43 ° C ) ( 3 minutes and, after washing and drying, the Kodaloid

at

1

.

.

may

be stripped

may

also be re-

off.

d. The silver stain on moved by swabbing with

[SS-1]

the gelatin backing of films the following solution:

Iodine-Cyanide Stain Remover Avoirdupois 18 grains 36 grains 4 ounces

Iodine crystals

Potassium Cyanide (Poison!) Water to make

This solution rapidly dissolves the advisable to protect the emulsion side

under

c.

III. tains

silver first

Metric 1.3 2.5

grams grams

125.0 cc

image so that

it

is

usually

with Kodaloid as described

before treatment.

Yellow Silver Sulphide Stain.

an excess of

silver, this is

If

a hypo alum bath con-

converted to colloidal silver sulphide by

the free sulphur in the bath and this deposits in the highlights of a


STAINS

under certain conditions, as a yellow

print,

tions

ON NEGATIVES AND PRINTS

where a nucleus

247

In the shadow por-

stain.

for a deposition exists, the sulphide apparently

deposited in a coarser condition, and the resulting tone

is

is

not materially

affected.

stain may be prevented by maintaining the temperature hypo alum bath not higher than 125° F. (52° C.) and by adding further quantities of hypo solution free from silver, as the toning bath

The yellow

of the

ages.

When

negatives or prints are treated with Farmer's reducer (ferri-

cyanide-hypo) a yellow stain invariably remains

if

reduce a dense portion of the image completely. of silver sulphide;

it

may

iodide in excess of this is

apt to result.

in

a second

Removal

35%

hypo.

0.5%

— Since the

particles

finer than the image proper, a

such as a

1%

If the permanganate treatment

followed by immersion in a

weak

weak

is

may

used,

be used for it

should be

bisulphite solution to clear

up the

stain formed.

To Summarize.

— A yellow

following substances:

silver,

stain

may

consist of one or

more

cided to attempt

its

in case the stained

treatment.

This

Then is

removal,

first

photograph

find out

of the

silver sulphide, silver halide or photo-

halide together with oxidation products of the developer.

stain.

compos-

solvent of

solution of potassium cyanide (a deadly

solution of potassium permanganate,

treating the print.

brown

slowed up greatly, immerse the negative

bath containing

much

If a quantity of

usually being sufficient.

of Silver Sulphide Stain.

ing the stain are

attempted to

added, trouble from slow or incomplete fixation

If fixation is

fixing

silver sulphide,

poison) or a

is

is

be prevented by the addition of potassium

1%

iodide to the fixing bath,

it

This stain consists

is

make

If

it

is

a copy through a suitable

de-

filter

ruined completely in the subsequent

by a preliminary

done by cutting a narrow

test the exact

strip

nature of the

from the edge of the

washing and bleaching and redeveloping as above.

film,

If the stain is en-

removed and is not replaced by a black deposit, the stain is pure oxidation stain and the entire negative may be treated in this way. If the stain is only partially removed, treat the narrow strip with cyanide as for the removal of silver stain, wash well, and if a transparent yellow tirely

stain remains, treat this as for oxidation stain. in

removing the stains from the narrow

The degree

procedure necessary for the rest of the negative. The stained gelatin backing of films may be removed by ing the emulsion surface

by squeegeeing

of success

strip will serve as a guide to the

it

first

protect-

onto a sheet of Kodaloid, and


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

248

subsequently soaking the film (so protected) in warm, dilute sulphuric acid solution (page 246).

MISCELLANEOUS STAINS Yellowish-Brown with iron or iron rust.

If these reels are rusty, the rust

reels.

winding and

The

settle

may

stain

ammonium

A

roll film or

re-

stain.

50%

solution of

5%

solution of

removed by bleaching and redeveloping

stain.

â&#x20AC;&#x201D; This occurs

Brown Scum.

during

off

deep red coloration indicates the presence

stains are usually

when removing developer

oping

be scraped

be identified by placing a drop of a

thiocyanate.

The

of iron.

may

between the convolutions of the film causing the

on the stain and then adding a drop of a

nitric acid

as

â&#x20AC;&#x201D;

Stains. These are usually caused by contact Motion picture film is usually wound on iron film

motion picture

in

deep tank development when devel-

film.

If the developer does not contain

enough preservative, a layer of insoluble oxidation product of the developer forms as a scum on the surface and this is picked up by the film.

The scum forms most is

readily on the surface of the fixing bath

if

it

allowed to stand for any length of time, for instance, over the week

end.

When

the bath

is

any hydrogen sulphide

exhausted and contains an excess of silver in the air reacts

salts,

with the silver thiosulphate at

the surface of the liquid, forming silver sulphide which floats as a scum.

This

picked up when the film

is

is

immersed

in or

withdrawn from the

solution.

A

brown scum has

a peculiar appearance under the microscope

and

characterized by a series of cracks or fissures which are formed the

scum

broken up on immersion of the film

is

in the tank.

page 41 shows an enlargement of such a scum fissures are

is

to

morning

made by Fig. 20,

Figure 21,

which the cracks or

very pronounced.

The most film

in

is

when

effective

means

of preventing

brown scum markings on the

skim the surface of both the developer and

fixing

bath each

either with the edge of a sheet of blotting paper, or a

skimmer

stretching several layers of cheesecloth over a wire frame (see

page 40).

The width

of the

skimmer should be adjusted

to

fit

the width of the tank for most efficient results.

Scum markings can

occasionally be removed

by the bleach and

re-

development method given on page 241, or by bathing the film in a 1% solution of potassium cyanide {this chemical is very poisonous and


ON NEGATIVES AND PRINTS

STAINS

Weak

should be always handled with eare).

249

cyanide also attacks the

image and the film should therefore be removed and washed thoroughly as soon as any reduction occurs. silver

Green Stain or Dichroic Fog,

— Dichroic fog appears

lowish or reddish green metallic sheen flected light, or a pinkish tint

ing

by transmitted

it

light.

when a

film

when looking through

is

as a yel-

examined by

re-

the film or examin-

In view of this dual character

called

is

it

dichroic or two-colored fog.

When examined

under the ultra-microscope the fog

of extremely fine particles

to consist of metallic silver.

The

size of the particles

by transmitted light, those that are red those which are green or blue. color

Dichroic fog

is

is

seen to consist

which by chemical analysis have been shown

always formed either

fixing bath.

determines their

in color being smaller

than

in i. the developer or 2. the

Dichroic Fog in the Developer. In order that the deposition may take place in the developer some solvent of silver bromide, such as hypo, ammonia, or an excess of sulphite or carbonate, must be present, when under certain conditions the dissolved silver salt is reduced I.

of fog

to metallic silver in a

very

fine

state of division, particularly in the

shadows or unexposed portions of the emulsion where no bromide is liberated during development. A pyro-ammonia developer is apt to give dichroic fog especially with fine grained emulsions for this reason.

Some in a

of the factors

which contribute

to the formation of dichroic fog

developer are as follows:

a.

Presence of Sulphide and

a Silver Solvent.

—A

trace of so-

dium sulphide in a developer in the presence of a silver solvent such as hypo favors the formation of dichroic fog, due probably to the fact that the sodium sulphide first precipitates miriute particles of silver sulphide on the surface of the emulsion and these in turn act as nuclei for physical development."

Hypo

is

apt to be transferred to the developer

by wooden motion picture film developing racks which have been incompletely washed, or by film hangers which tend to retain hypo. Sodium sulphide can form in a developer as a result of the presence of bacteria,

which reduce the sodium sulphite

quent sterilization of the tanks

and

sodium sulphide.^ ^

L.

The Staining

Dundon.

J. I.

Crabtree.

Fre-

a satisfactory preventive.

Properties of Motion Picture Developers " by J. 25, 108 (1926). Traxs. Soc. Mot. Fict. lliiy. 11 " Sulphide Fog by Bacteria in Motion Picture Developers " by

10 "

M.

is

to

N

I.

Crabtree and

.

Trans. Soc. Mot. Pict. Eug. No. 19, 28 (1924).

M.

L.

Dundon


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

250

Fine grained emulsions

which the grains of

in

silver halide are

very

small and. therefore, more readily soluble are most susceptible to this

form of

fog. especially

if

the development

Prolonged Immersion

b.

is left

forced.

is

Used Developer.

in a

— In case

accidentally in a well-used developer over night, a

form of dichroic fog largely

is

Ordinary dichroic fog

produced.

on the surface of the emulsion, but

The

ates the entire gelatin layer.

more

is

filled

usually

by

trans-

light.

The

usually brown

mitted light and possesses a coppery luster by reflected

shadows are often

is

type thoroughly perme-

this

deposit

a film

insidious

with a deposit so dense that

it

is

impossible to

In some portions the negative image

obtain satisfactory prints.

may

also be reversed completely. c.

Presence of Sulphide

in a

Preliminary Desensitizer Bath.

— A desensitizer bath may become contaminated

with sodium sulphide

as a result of bacterial growth acting on the sulphite carried into the

bath from the developer or the fixing bath by film sulphide

carried into the developer

is

produced as described under 2.

erally

or

a.

by

above.

— Dichroic fog

Dichroic Fog in the Fixing Bath. formed

if it is

old

in the fixing

bath, especially

and exhausted, when

and partially spent developer.

it

if

the fixing bath

is is

most gennot acid,

contains an excess of dissolved silver

In such a case, as the silver halide

slowly dissolved out of the emulsion, metallic silver

When this may be

clips.

the film, dichroic fog

it

by the developer present.

is

is

reduced to finely divided

It is

possible also to get di-

chroic fog with a fresh fixing bath of plain hypo, because the silver salt is

redeveloped back to dichroic silver by the developer carried over by

the film to the fixing bath. of the film

are

is

This

is

abnormally thick, and

especially true if

if

the gelatin coating

the developing and fixing solutions

warm. The developer does not have time to diffuse out of the gelatin hypo begins to dissolve away the silver halide. which is

film before the

reduced in situ to dichroic

silver.

A

slow fixing emulsion

is

apt to give

dichroic fog for the above reasons.

Dichroic fog can also occur

in

a fresh fixing bath

if

two films or

prints stick together face to face, thus forming local pockets containing

developer.

Such a condition

is

namely, an insufficiency of h\-po Stencil effects are

negative or print film in the fixing

ideal for the formation of dichroic fog, in the

presence of an excess of developer.

sometimes produced

in the

when another film with dense bath. The result is that the

chroic fog except in those places where

it

was

in

shadow portions

of a

lettering adheres to the film

is

covered with di-

contact with the lettering.


ON NEGATIVES AND PRINTS

STAINS This

251

because the developer in contact with the clear portions of the

is

negative

lettered

comparatively fresh, but wherever the lettering

is

occurs, the developer

formed

comparatively exhausted, so that no fog

is

in the region of the lettering,

The potassium bromide which

is

thus producing the stencil

formed locally

is

effect.

in excess in the region

of the lettering (as a product of development), also tends to retard the

formation of the fog, thus accentuating the stencil

Prevention of Dichroic Fog.

effect.

â&#x20AC;&#x201D; Dichroic fog can be prevented as

follows:

By

a.

and

keeping the fixing bath acid by renewing at frequent intervals,

possible rinsing the film well before fixing, or using an acid

if

bath

rinse

between

developing

and

fixing.

In

this

quantity of developer transferred to the fixing bath

manner the reduced to a

is

minimum.

By

b.

agitating the film at regular

development and

By

c.

liter

silver halide dissolved is

intervals during both

adding potassium iodide to the developer, about

or 22 grains per 32 ounces.

which

and frequent

fixation.

This has the

by solvents

reduced to silver only with

dichroic fog to be formed d. If there is a

sodium sulphide

is

in

1.5

grams per

effect of converting

the developer to

silver

difficulty, so that the

any

iodide,

tendency for

restrained.

slimy deposit on the walls of the developing tanks,

may

be formed as a result of the action of bacteria or

fungi on the sulphite present in the developer. The sodium sulphide is removed from the developer by contact with a silver halide emulsion,

which

is

converted to silver sulphide so that the fogging effect usually

disappears after developing a certain quantity of film. for a

After standing

few days, the bacteria form a further quantity of sodium sulphide

which again produces

stain.

The immediate remedy is to add lead acetate to the developer in the proportion of i gram per liter (60 grains per gallon) of solution. The acetate should be dissolved in a small quantity of water and added slowly with stirring.

harm

if

Usually a milky precipitate forms but this does no

allowed to settle out.

In order to prevent the growth of bacteria,

the tank should be cleaned out at frequent intervals by scrubbing the walls with hot water

A pound

and chloride

of lime obtainable at

any drug or paint

two of the chloride of lime should be added to a bucket of water, and the walls of the tank scrubbed thoroughly with the

store.

milky solution. water.

or

Then

flush the walls thoroughly several times with plain


:

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

252

Removal of Dichroic Fog. ticles of silver in

— Since

dichroic fog consists of par-

a finer state of division than the particles composing

the image, they are more readily attacked and therefore dissolved by solvents of silver such as potassium cyanide, acid permanganate, etc.

may be

Advantage

Bathe the

a.

taken of this fact in removing the fog as follows

film in a

%

i

solution of potassium cyanide

As soon

film gently with a tuft of cotton.

image occur, wash well

tion of the

in

as

any

and rub the

visible signs of reduc-

running water (note remarks about

poisonous nature of potassium cyanide on page 271). b. In place of cyanide the less toxic thiocarbamide, or thiourea,

Harden the film first Then bathe the film page 234) be used.

.

in

may

an alkaline solution of formalin (see

in the following solution:

Acid Thiourea Stain Remover

[SS-2]

Metric

Avoirdupois

Thiourea

20 grains 20 grains 4 ounces

Citric Acid Water to make

1 .4

1.4

grams grams

125.0 cc

Treat the film with a weak solution of Farmer's reducer made by little potassium ferricyanide to a 5% solution of hypo, or with

c.

adding a

a weak acid permanganate solution (about 0.5%). d.

The

insidious form of dichroic fog resulting from leaving film over

night in a developer first,

may

harden the negative for

page 234), wash, and

(see

be removed fairly satisfactorily as follows: 5

minutes

treat for 5

neutral potassium permanganate.

h3^o for and dry.

An

e.

5

a

an alkaline formalin solution

Then wash, and

minutes, and finally clear in a

10%

in plain

30%

bisulphite solution,

wash

warm

warm solution.^- This can readily be

solution of acid

removing dichroic if

fog.

seen

hypo when the image A hypo bath is,

preciably in a very few minutes.

hours

fix

ordinary fresh acid fixing bath will slowly dissolve silver

especially in in

in

minutes with a 0.5% solution of

by placing a print

will

be reduced ap-

therefore, useful for

in the hypo bath for 24 removed, though the action

Allow the film to stand

necessary or longer, until the fog

is

can be hastened by gently warming, not above 90°F. (32 °C.).

Blue-Green Stain and Scum.

—A

general bluish-green stain

often caused, especially with certain grades of matte paper,

is

by using an

exhausted chrome alum stop bath or a fixing bath at high temperatures. 12

and

"

The Reducing Action

J. I.

Crabtree.

/.

of Fixing Baths on the Silver Image," by H. D. Russell

Soc. Mot. Pict. Eng. 18, 371-97

(March 1932).


STAINS

ON NEGATIVES AND PRINTS

253

The remedy is to use a fresh bath at normal temperatures, because there It is preferable is no known way of subsequently removing this stain. to use a

alum

potassium alum fixing bath for papers, rather than a chrome tendency of the latter.

fixing bath, because of the slight staining

Fig. 94

When

a

â&#x20AC;&#x201D; Print

chrome alum

from film stained with chrome alum scum.

fixing

bath

is

used in conjunction with a de-

veloper having a high carbonate concentration, the gelatin of a film or plate

is

often stained green, particularly

temperatures.

with

5%

The

potassium

if

the fixing bath

is

used at high

removed by treating the film should be hardened first in the

stain can usually be citrate.

The

film

alkaline formalin solution (page 234) because the citrate softens the gelatin greatly. it is

A

Provided the green stain

is

uniform over the entire

film,

usually not objectionable from a photographic standpoint. bluish-green

scum

is

likewise apt to form on films or plates

using a chrome alum hardening rinse bath or fixing bath consists of

chromium hydroxide and may be a

(

Fig. 94)

.

when This

result of a. insufficient

agitation on placing the film in the rinse bath or fixing bath, b. the use of

an exhausted or insufficiently acid rinse or fixing bath, or c. the use of a much alkali. If such a scum forms on the film

developer containing too this it is

should be removed by swabbing with cotton before drying, otherwise almost impossible to remove it after the film has dried.

Yellow Stains on Glossy Prints. often caused by

â&#x20AC;&#x201D; Deep lemon yellow

insufficient fixation of glossy prints

stains are

which have been


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

254

developed with a developer containing potassium iodide (sometimes

added

The potassium

to prevent abrasion).

iodide converts the surface

layer of the silver bromide emulsion to silver iodide, which

much more

yellow and which fixes

is

deep lemon

slowly than silver bromide and does

not darken on exposure to light.

The

removed completely by bathing

stain can usually be

in a fresh

fixing bath.

Brown tives

Stains.

â&#x20AC;&#x201D; Local brown stains are sometimes formed on nega-

which have been stored

in those parts

The

velope.

which were

stain

is

in

paper envelopes, the stains being present

in contact with the pasted

seam

of the en-

a result of decomposition of acid products which

attack the silver image.

Such stains can often be partially removed by bleaching and redeveloping as described on page 241, but usually the negative cannot be restored completely

The

stains

at the edge

may

by

and not

or shellac adhesive,

placing the seam of the envelope

a.

in the center, b. using

and

that the emulsion side tive in

this treatment.

be prevented by

only a pure starch, dextrine,

by inserting the negative in away from the seam. Dipping

c.

is

a nitrocellulose varnish

will also

the envelope so the entire nega-

minimize the danger of formation

of such stains.

Dye

Stains,

â&#x20AC;&#x201D;-During

recent years, dyes have

come

into

more and

tensive use for sensitizing emulsions, for anti-halation backings, " internal " filters such as in duplicate negative emulsions. stains are encountered as a result of

some

The dyes used

in the film after processing.

exfor

Occasionally

dye remaining locally such purposes are mostly

of the for

water soluble or are discharged from the film in an alkaline solution such as a developer.

If traces of the

A

color sometimes returns.

dye are retained by the

served in a processed panchromatic film or plate

is

the sensitizing dye remaining in the gelatin layer. tionable and harmless,

it

caused by traces of

Although unobjec-

can be removed by bleaching and redeveloping

as outlined on page 241 or

gram (15

film, the

residual pink or blue color sometimes ob-

by treatment with a solution containing i and 12 cc (3 drams) of concentrated

grains) of sodium nitrite

hydrochloric acid per

liter

(32 ounces).

Traces of the pink or blue anti-halation dye sometimes remain in amateur roll films after processing and give rise to a peculiar mottled appearance.

Such stains are entirely harmless photographically as


STAIXS

ON NEGATIVES AND PRINTS

they do not absorb the printing

by bathing

in

255

They may be removed,

light.

if

desired,

an 0.5% sokition of sodium sulphite and then washing

thoroughly. Desensitizing dyes occasionally cause stains on films or plates treated

with a solution of the dye.

For the most part, such stains

nored as they do not absorb light when printing.

According

may

to

be

ig-

Wright

'â&#x20AC;˘'

by safranine dyes may be removed from a fixed and if desired, by treating with an acid solusodium nitrite as given above. Faint green stains produced

stains caused

thoroughly washed negative, tion of

when using Pinakryptol green

are harmless.

Stains due to dyes, indelible pencils, or red and black writing inks

are removed

photographically or by bleaching and redeveloping as In the case of some samples of red ink a slight

described on page 241.

trace of stain remains after the chemical treatment, but this can be re-

moved photographically.

may

Figures

95A and 95B

illustrate

how

ink stains

be removed completely, by chemical treatment.

Figure 95A is a copy on an ordinary film of a photograph stained with " waterproof "' red ink. Figure 95 B is a copy of the same photograph after the red stain was removed by bleaching in the permanganate-chloride bath and redevelop-

No

ing.

sign of the stain

is

visible.

Stains from Vegetable Matter.

â&#x20AC;&#x201D; Yellowish brown

highlights of prints are sometimes caused

stains in the

by the presence

in the

wash

water of dissolved extracts from decayed vegetable matter and the bark of trees.

It is a difficult

matter to remove economically the coloring

matter from such waters, but filtration through activated charcoal

The

usually effective.

print stains

may

is

be removed by bleaching and

redeveloping as described on page 241.

The

use of a bisulphite fixing bath (Formula F-24) in

gives less stain since the

alum present

in the regular acid

many

cases

fixing

bath

tends to mordant the coloring matter onto the print.

Blue Stains.

â&#x20AC;&#x201D; These occur usually on paper

prints after treatment

with solutions containing ferro- or ferricyanides and consist of Prussian blue formed by reaction of the ferro- or ferricyanide with an iron salt

which

may

be present

iron or iron oxide I'i

5,

may

in

some

of the reacting chemicals.

also be present in the

"Treating Stained Negatives" by

1931).

F. V.

Wright.

Particles of

wash water or processing Bril. J. Phot. 78, 334

(June


256

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

trays.

The

removed by treatment and then washing thoroughly.

stains can usually be

tion of potassium oxalate

A.

B.

Copy

Copy

of print

showing

in a

io%

solu-

stain.

of print after treatment of print in bleach

and redeveloper

solutions.

â&#x20AC;&#x201D;

Illustrating the use of permanganate 95 bleach for removal of a dye stain on a print.

Fig.

Stains During After Treatment. ing of negative or positive materials

â&#x20AC;&#x201D; Thorough is

fi.xation

and wash-

absolutely necessary in order

to avoid stains during subsequent reduction, intensification, or toning

processes.

With mercury

cient fixing or

intensification, stains will result

from

insuffi-

washing or too short washing after bleaching and before


STAINS ON NEGATIVES According to Wright

darkening.

^*

such stains

of the following treatments: a. lengthy

bath;

b.

AND PRINTS may

immersion

be removed by one

in a fresh acid fixing

bleaching and redevelopment, according to the method de-

scribed on page 241 but this will not remove silver stains. ,

ing and before clearing, to

desirable to

wash

Brown

in several

stains left

2%

Summary

changes of acidified water (30 cc of 28% ( i ounce of 28% acetic acid per 32 ounces)

by potassium permanganate may be eliminated by

metabisulphite or bisulphite solution.

of All

Types of

Stains.

â&#x20AC;&#x201D; Table 13 on page 258 gives a

of the majority of the classes of stains, their cause,

prevention, and removal as discussed in this chapter.

erence should be 14

'â&#x20AC;˘

Wright

it is

rinse briefly in plain water before clearing with bisulphite.

bathing in a

summary

After bleach-

remove the soluble mercury compounds,

acetic acid per liter of water)

and then

257

Stains on

made

to

of

ref-

to the text as noted.

by F. P. Wright. Brit. J. Phot. 78, 321 (May 29, 1931). removing other miscellaneous stains but the authors confirm these results which probably apply to specific cases.

Prints "

also gives instructions for

have been unable

method

For details


258

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

^p.•s

^ .S

"

-^

*J

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STAINS

ON NEGATIVES AND PRINTS

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259


PHOTOGRAPHIC CHEMIC\LS AND SOLUTIONS

260

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STAINS ON NEGATIVES

rt

M

E

AND PRINTS

261


CHAPTER

XII

CLEANING PHOTOGRAPHIC PROCESSING APPARATUS AND REMOVAL OF STAINS FROM THE HANDS AND CLOTHING Apparatus used for mixing and containing photographic chemicals and solutions becomes discolored and sometimes coated with decomposiIn certain cases this does no harm

tion products of the solutions.

especially

but

if

the container

much

it is

emptied.

is

always used for the same kind of solution

better technique to clean all containers each time they are

Small bottles and old trays are sometimes very

clean satisfactorily and

new ones. The simplest method is

difficult to

and use

better to discard such receptacles

of cleaning a tray or small tank

several times with water

This procedure

is

it

wash

to

is

and then wipe the surfaces with a clean

it

out

cloth.

preferable in the case of trays, at least, to the constant

use of a strong oxidizing solution such as the usual acid bichromate tray cleaner which tends to etch the enamel slightly each time

Such cleaning agents should be resorted

to only

when

is

used.

stains

cling

it

tenaciously to the surface.

Most cleaning

solutions are either strong alkalis or acids

and should be

used with the same discretion given these chemicals when mixing photographic solutions.

The

principle of a cleaning solution

the stain or deposit and changes in the cleaning

agent or

may

it

is

that

it

acts on

over to a soluble form which dissolves

Sometimes the

be washed out with water.

cleaning agent merely softens up the deposit sufficiently so that

it

may

be removed by the use of an abrading substance like sand or glass beads.

CLASSIFICATION OF STAINS Oxidized Developer Stains. brown or yellowish-brown

color.

â&#x20AC;&#x201D; Developer

Fresh stains

stains are usually of a

may

often be removed

washing the vessel with soap and water and wiping with a stains require the use of

cloth.

an oxidizing solution such as acid bichromate of

the following composition:

[TC-1] Water Potassium Bichromate Sulpliuric Acid, C. P. (concentrated).

Add

by

Severe

Avoirdupois

Metric

32 ounces

1.0 liter

^ .

.

ounces

3 ounces

90.0 grams 96.0 cc

the acid slowly with stirring to the bichromate solution.


CLEANING PROCESSING APPARATUS

263

For use: Pour a small volume of the solution into the vessel Rinse around so that it has access to all parts, then pour

to

cleaned.

and wash the container

until all traces of the solution

it

be out

have disappeared.

Warning: This solution should not be used with chromium plated metal trays because it tends to destroy the copper undercoating. Such surfaces and stainless steel are best cleaned

and a

be permitted to stand

in

metal containers for any length of time because

A

of danger of their corrosive action.

known to corrode stainless tanks made of this material.

been or

Other solutions which (followed

by treatment

manganese

stain)

40%

;

by scrubbing with a brush

Strongly oxidizing solutions should never

powder.

fine scouring

will

5%

in

steel

ferricyanide-bromide bleach has

and

it

should not be used in trays

be found useful are bisulphite to

i%

permanganate

remove the residual brown

sodium hydroxide (caustic soda)

;

and any of

the strong mineral acids, sulphuric, hydrochloric, and nitric.

removal of the

stain, the vessel should

After

be washed thoroughly to insure

complete removal of the cleaning agent.

Sulphur and Silver Sulphide Deposits.

â&#x20AC;&#x201D; When

a fixing bath

sulphurizes, the colloidal sulphur formed adheres tenaciously to the

walls of the vessel. silver sulphide is

If the fixing

formed and

the walls of the vessel.

bath has been

this deposits as a

in use for

some time,

brownish-black layer on

Bottles used for storing

hypo alum toning baths

often exhibit this type of deposit.

A

hot concentrated solution of sodium sulphite (about

usually dissolve sulphur.

A warm 10%

(sometimes called Oakite) If the deposit

will also dissolve a

adheres to the surface,

it

20%)

will

solution of tri-sodium phosphate

may

sulphur deposit easily.

be loosened by adding glass

beads or sand to the vessel and shaking vigorously.

A 1%

solution of permanganate

sulphide deposit. to

is

often effective in removing a silver

This treatment should be followed with

5%

bisulphite

remove the manganese dioxide formed. Another useful cleaning agent

(about 2%).

This substance

is

is

a dilute solution of potassium cyanide

a deadly poison

and a solution

emits fumes of poisonous hydrocyanic acid so that in a well ventilated room.

such a solution.

It

it

water

Care should also be taken when discarding

should never be added to a sink where any acid

standing or poisonous hydrogen cyanide gas will be formed.

stream of water should be run into the sink when the solution

down

in

should be used only

the drain.

Silver Deposits.

â&#x20AC;&#x201D; Most

A is

is

strong

poured

so-called fine grain developers are essen-


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

264

tially physical

solution

The

developers and deposit a sludge of silver in the developing

and on the

sides of the developer container.

(Formula In-5) deposits a very heavy layer of Such stains may be removed by a silver solvent

silver intensifier

on the container.

silver

such as

acid-bichromate,

I.

cyanide-hypo), or IVIost

Farmer's reducer (Formula R-4)

2.

(ferri-

iodine-cyanide (see page 246).

3.

metals or alloys tend to accumulate a plating of silver when

immersed

in a

With metal

used fixing bath which contains dissolved silver

and

film hangers

spongy nature and

their

clips,

salts.

such deposits occasionally are of a

rough surface scratches the gelatin emulsion of

films or plates, particularly

if

the solution temperature rises above 70°F.

(2I°C.).

There are four methods of removing such deposits, as follows: Acetic Acid Treatment. Soak the hangers or clips

a.

hour

in a tray or

tank

filled

The

luted with 9 parts of water).

wash with

10%

with

acetic acid

(

i

for

an

part glacial acid di-

acid tends to loosen the deposit.

Then

and scrub the deposit with a stiff brush. Most deposits can be loosened and removed by this treatment. b. Acid Bichromate Treatment. If a silver deposit clings tenaclear water

ciously to the metal hanger,

it is

necessary to treat

such as acid bichromate, which will dissolve the

on page 262 part of

The

is

TC-i

satisfactory for use provided

it is

with a solution

Formula TC-i

diluted as follows:

i

to 2 parts of water.

length of time the hangers or clips should remain in this solution

depends on the quantity of minutes

is

may

silver to

usually sufficient.

solution, rinse

which

it

silver.

When

be removed.

them thoroughly and brush

adhere to the hanger or

An immersion

of 10

the articles are removed from the

clip.

off

any reddish colored

scale

It is advisable to use a glass or

hard-rubber tray as a container for the cleaning solution rather than an

Note chromium plated

enamelled tray which becomes etched slowly by the solution.

warning

against the use of acid bichromate for cleaning

apparatus, given on page c.

2

63

Tri-Sodium Phosphate Treatment.

cially useful for cleaning silver

— This

method

is

espe-

deposits which have formed as a spongy

layer in gelatin on film hangers or clips.

The equipment should be

allowed to soak for several minutes in a boiling solution of trisodium

phosphate

(about

thoroughly with a d.

10 to stiff

Sandblasting.

15%).

The

surface

should

be scrubbed

brush after the phosphate treatment.

— Heavy

deposits on partially corroded clips or

hangers are best removed by sandblasting.


CLEANING PROCESSING APPARATUS Dye

Stains.

265

â&#x20AC;&#x201D; Enameled trays or tanks which have been used with

strongly alkaline developers or caustic solutions gradually lose their glossy surface and

become roughened, when they

discolor easily.

such containers are used with dye solutions, the dye pores of the enamel, and

it

is

is

If

taken up in the

a very difficult matter to remove

it

com-

^lany dye stains may be oxidized by treatment with a 0.5% solution of potassium permanganate acidified with about 0.5% sulphuric If a manganese dioxide stain remains afterwards, this may be acid. pletely,

removed by treating with a 5% bisulphite solution. Basic dye stains often be removed by adding a little glacial acetic acid to the tray and rinsing it around several times. If the stain is not removed, a more

may

25%)

dilute solution of the acid (about

should be allowed to stand in

the vessel overnight.

Trays stained with acid dyes can often be cleaned up merely by wash-

and scrubbing with a brush. Badly discolored trays which are not cleaned up by treatment with acid permanganate should be discarded as it is not worth the time to ing with water

attempt to clean them.

If

a badly colored tray

intended to be used

is

again for the same dye solution, the stain obviously

is

harmless and the

tray need not be discarded.

Slime, Fungus, Mold, Etc.

â&#x20AC;&#x201D; Large

tanks of wood, Alberene, or

stoneware, after several weeks of use as containers for developers, be-

come coated with a

layer of slime.

The

slime

gelatin, organic matter, fungus growths, molds,

is

composed

and

chiefly of

dust.

Certain fungi or molds have the property of reacting with the sulphite in the developer

and converting

fogging agent. ^

Trouble from

it

to

sodium sulphide which

this source

may

is

a strong

be avoided entirely by

tank at regular intervals, especially during warm weather. Stone tanks can be sterilized by scrubbing the sides and bottom thor-

sterilizing the

oughly with solid calcium hypochlorite or chloride of lime, also called bleaching powder, to which enough water has been added to form a paste.

The tank should then be

rinsed thoroughly (five or six times)

with clear water.

For wooden tanks, the walls should be scrubbed thoroughly with a wire brush, and then the tank filled with sodium hypochlorite solution (i part hypochlorite solution to 6 parts of water)

overnight. 1

" Sulphide

Dundon and

and allowed

to stand

The tank should be emptied the next morning, given anFog Produced by Bacteria

J. I.

Crabtree.

in

Motion Picture Developers

" by

Trans. Soc. Mot. Pict. Eng. No. 19, 28 (1924)-

M.

L.


A

FHOTOGRAPHIC CHEMICALS AXD SOLUTIONS

266

other thorough scrubbing and five or six washings, before being used again.

Method

of Preparing

Sodium Hypochlorite

stock solution of fajpochlorite

is

Solution.

prepared by making up a

4'

V

solution

and adding 10^ sodium carbonate solution The solution is then allowed to stand The all the precipitate settles to the bottom of the container. liquid then should be drawn oflf for use as a stock solution.

of calcium hypochlorite until

until

clear

no more precipitate forms.

REMOVAL OF STAINS FROM THE HANDS 1.

Developer and Ink Stains.

hands

— The removal of stains from ^

The

a comparatively simple matter.

is

the

following stain remo\er

works equall}- well with most ink stains as with developer stains. For such stams. immerse the hands in a small volume of the following solution:

i;

Potassium Permanganate Sulphuric

Add

Metric

Avoirdupois ounces 32

Water .\civl.

C. P.

concentrated

1.0 liter

ounce

minims

75

15.0 arams 5.0 cc

the sulphuric acid slowly to the permanganate solution while

Xotc: See suggestions on dissolving

stirring the latter solution rapidly.

permanganate

in

water on page 171.

After bathing in the permanganate bath, rinse in water and apply a

5fc solution of sodium bisulphite or immerse the hands in a fresh acid fixing bath. If the one application is not sufficient, rinse the hands thor-

oughly and repeat the operation.

Warming

the permanganate solution

will assbt in remo\-ing obstinate stains.

This treatment

will

remove the stains caused by any of the ordinary

writing or stamping inks, as well as practically stains. 2.

Silver Stains.

— Treatment of

all

silver stains

forms of develop)er

with the permanga-

nate solution given above wiU remove slight stains but severe stains,

such as are produced by

silver nitrate, should

following methods. a.

Bleach Bath Treatment.

be treated by any of the

— This method

consists in

immersing

or washing the silver stain with an ordinar>- bleach bath used for sepia toning, or with the following solution:

Water Potassiam Ferricyanide Potassium Bromide

.\voirdupois

Metric

32 ounces

1.0 liter ?0.0 arams

1 1

ounce ounce

,?O.0

grams


CLEAXIXG PROCESSING APPAR.ATUS

267

Rinse and then immerse the hands in an acid hyjx) bath; then wash thoroughly.

Iodine-Cyanide Treatment.

b.

ferred, since this

— The

one uses cyanide which

is

method

first

a. is to

a deadly poison.

be pre-

If care is

used to avoid the presence of acid on the hands before the treatment and to

wash thoroughly

The

method.

after«-ards, there

solution to be used

is

is

no great danger from using

Metric

Avoirdupois

Water

Sodium

32 ouncres 145 grains 100 grains

or Potassium Cyanide

Iodine

quickly

down

the drain.

If CN'anide is

1 .0

10.0 6.7

Do

After use. wash the hands very thoroughly. tion in a sink unless a strong stream of water it

this

as follows:

is

liter

grams grams

not discard the solu-

running so as

to

wash

brought in contact with an acid,

the deadly poisonous hydrogen cyanide gas

formed.

is

REMOVAL OF STAINS FROM CLOTHING Developer and Ink Stains. White Fabrics. The acid permanganate

I.

a.

solution

recommended

previously for the hands (page 266) will likewise remove stains from

cotton fabrics, although the fabric

A

less

harmful method

is

is

apt to be weakened in the process.

the following: soak the stained portion of the

wash powder

fabric in a 5^c solution of oxalic acid or acetic acid for 2 minutes, for

I

or

2 minutes, then apply a saturated solution of bleaching

(calcium hj-pochlorite

) .

If after 10

minutes the stain does not disap-

wash and reapply the acid solution and. if necessary, the hj^pochlorite solution, and finally wash thoroughly. Both the acid permanganate and the oxalic acid and bleaching powder

pear,

A

treatment should be restricted to cotton fabrics.

ment and one which sists of

is fairly

Care must be used with

of treatment, however, to avoid the possibility of

of the fabric. b.

safe for use with all types of fabrics con-

bathing in hydrogen peroxide solution.

any tvpe

less severe treat-

Colored Fabrics.

break-down

— The permanganate bath given on page 266

should never be used with colored fabrics unless a

trial

on a small area

shows that the solution does not bleach out the color. A should next be made with the oxalic acid and bleaching powder

of the fabric trial

treatment which will usually remove color in the fabric.

If the

all stains

without

afi'ecting the

preliminary test shows any sign of affecting

the color in the fabric, a trial should be

made

of the p)eroxide treatment.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

268

2.

Silver Stains. a.

rics

White Fabrics.

Silver stains

by the same methods

A

from the hands.

plain

i%

for

removal of such stains

also satisfactory for use with cotton fabrics but

the addition of iodide

is

silk or wool.

is

be removed from white fab-

solution of potassium cyanide without

should not be used on

cyanide

may

recommended

as

Warning: As mentioned previously,

Adequate

a deadly poison and should be handled with care.

ventilation in the

workroom, freedom from contact with any

when discarding

a strong flow of water

acid,

in a sink are the usual

it

and

precau-

tions to be observed.

A

removal

less severe solution for silver stain

is

the regular ferri-

cyanide-bromide bleach bath followed by hypo, given below under b.

Colored Fabrics.

10 minutes, wash for

io%

or plain

2

— Treat

minutes, and then apply an acid fixing solution

Then wash

hypo.

thoroughly.

Water Potassium Ferricyanide Potassium Bromide If the stain is not

b.

with the following bleach bath for

Avoirdupois

Metric

ounces ounce ounce

1.0 liter

32 1

}4

30.0 7.5

grams grams

removed with one application, the treatment should

be repeated.

Iodine Stains.

— Iodine

moved by applying

stains

on the hands or clothing

may

be

re-

weak solution of hypo (io%) or a few drops of The hypo or fixing bath should, of course, be a fresh fixing bath. removed from the fabric by washing. The dye in some fabrics may be affected by the acid fixing bath. A preliminary test should be made and if any action on the color is observed, the bath should be diluted a

before application.

Dye

Stains.

classified into

— Dyes used

for

photographic work

two groups, acid dyes and basic dyes.

may

be roughly

Other classes of

dyes are used in connection with color processes but these are not em-

ployed very extensively.

Most

acid dyes will dye gelatin or fabrics di-

rectly or in the presence of a trace of acetic acid.

Basic dyes are usu-

employed following treatment with a mordanting solution. The mordant attaches itself to the gelatin or fabric and the dye becomes

ally

attached to the mordant.

When wash the

attempting to remove a dye stain from the hands or clothing, stain thoroughly with water, as

If the stain

is

many

dyes are water soluble.

not removed, wash next with denatured or

wood

alcohol.


CLEANING PROCESSING APPARATUS If it is still

unaffected and

//

the fabric

is

269

white, treat with a

0.5%

solu-

permanganate containing about 0.25% sulphuric acid. Then rinse and moisten with 5% sodium bisulphite to remove any manganese dioxide stain and finally wash thoroughly with water. This tion of potassium

treatment will usually remove most dyes. If the fabric is colored, the acid

permanganate treatment should not

be used or the color will be bleached out of the fabric. stain should be moistened with dilute

the stain

is

Instead, the

ammonia (3%) and washed.

unaffected, the dye probably cannot be

removed without

If

also

destroying the color in the fabric.

Use of an Ink Eradicator.

â&#x20AC;&#x201D; The ordinary ink

eradicator which

usually consists of solutions of oxalic acid and hypochlorite, respectively, is

often effective in removing stains.

preliminary test should

first

As with

all

other treatments, a

be made on a small area of the fabric be-

fore applying the chemicals to the entire stained area. If

a stain

is

ods outlined,

especially difficult to it

is

remove from a fabric by the meth-

better to send the garment to a reliable dyer and

cleaner than to attempt further treatment. ]\Iany valuable hints on stain removal from fabrics will be found in

Farmer's Bulletin No. 14 issued by the U.

S.

Dept. of Agriculture (ob-

tainable from the Superintendent of Documents, Office,

Washington, D.

C,

at 5 cents per copy).

Government Printing


CHAPTER

XIII

GENERAL SUGGESTIONS AND PRECAUTIONS ON HANDLING PHOTOGRAPHIC CHEMICALS Only

a comparatively small

number

of photographic chemicals are

capable of producing harmful effects and no trouble need be anticipated

when handling them provided ordinary

care

is

exercised.

Skin irritation or dermatitis occasionally encountered by photographic

workers

often due to the careless use of a strong alkali or oxidizing

is

agent when attempting the elimination of a stain on the hands or arms rather than the direct action of

According

to

Dr.

S.

some common photographic chemical.

Overton, alkalis hold

of causative agents for dermatitis.^

the

body

is

covered with a

stated to be " far

more

cell

The

known

formation

tolerant to acids

first

place

among

the groups

surface layer or epidermis of

and

which are

as horn-cells

in stronger solutions

than

Alkalis have a macerating action on the keratin of the skin;

to alkalis.

and the horn

is to protect the more delicate become disorganized, separate, and thus allow

the function of which

cells,

structures beneath them,

the irritant to penetrate the

first line

of defense."

In the handling and mixing of photographic chemicals, unpleasant reactions

may become

manifest in one or more of the following ways: A. as

surface or skin effects from continued contact with specific chemicals,

B. as internal effects caused

by inhalation

of vapors or dust,

and absorp-

tion through the pores of the skin, C. a combination of effects

In the

first

place

it

A

and B.

should be clearly understood that the susceptibil-

chemical irritation depends to a large extent on the individual,

ity to

and that practically every chemical substance varying severity on the skin of

effects of

many

will

produce

irritating

persons, providing the

tion.

is handled repeatedly and under conditions favoring its reacWith some chemicals, only the smallest trace is required for cer-

tain

susceptible " individuals to produce a severe reaction as

substance

by ivy poisoning, which is caused by by the ivy in minute quantities.

for example,

given

off

The

following

list

is

shown,

compound

of substances represents a compilation of those

chemicals

commonly used

caution.

It

substance.

a chemical

in

photography which should be handled with

does not imply that everyone

Xo attempt has been made

1 "Discussion on Industrial Dermatoses." (June 1929).

is

likely to be affected

by each and

to give details of diagnosis Proc. Roy. Soc. Med. 22,

1

151-66


-

GENERAL SUGGESTIONS AND PRECAUTIONS

271

treatment for each material as such information can be obtained from a

known

physician and from the

texts

on industrial poisons and toxicol-

ogy, several of which are listed at the end of the chapter.

Gases and Liquids. rapher

is

â&#x20AC;&#x201D; The

most toxic gases

likely to be subjected are

to

which a photog-

hydrogen cyanide, sulphur dioxide,

hydrogen sulphide, ammonia, and fumes from formaldehyde, strong

and organic solvents. The importance oj adequate

acids,

ventilation

and good

circulation of air in

rooms where chemicals arc handled cannot be overestimated. For example, bad cases of headache have been known to occur in rooms where motion picture film was being cleaned with carbon tetrachloride

all

because of insufficient air circulation and change.

In such rooms, fresh

and withdrawn, but precautions near and around the cleaning machine

cool air should not only be admitted

should be taken to see that the air

The

does not remain stagnant during the ventilation process. tice,

obviously,

is

to provide

space or part of a machine where toxic gases are being given

scheme insures quick removal room. to the

known

best prac-

a hood and air exhaust fan adjacent to the

of the gas before

it

off.

This

can dissipate into the

In addition to causing headache, prolonged or frequent exposure

fumes of carbon tetrachloride

in a

poorly ventilated room has been

to bring on severe disorders of the liver and kidneys especially in

the case of an individual

who

has used alcohol freely.

Potassium cyanide is used only to a limited extent by modern photographers for special work such as reduction of negatives, rapid fixation, or for stain

removal (see Chapters

XI and XII).

poisonous when taken internally; 0.2 to 0.3 gram cause death and,

measure

to

when handling

wear rubber gloves

if

this chemical,

it

It is

deadly

(3 to 5 grains) will is

a good preventive

Cyanide

there are cuts on the hands.

should be stored in a locked cabinet when not in use and the user should

always wash his hands thoroughly after using

it.

potassium cyanide or a solution of the salt is brought in contact with any common acid, the very poisonous hydrogen cyanide gas is formed. It is important, therefore, to avoid using cyanide in a

When

solid

sink where any acid tion in the

is

room where

standing, and to see that there it is

to be used.

When

is

ample

the solution

is

ventila-

discarded,

a vigorous stream of water should be used to insure rapid and complete

removal of the solution from the sink. .Solvents " published by Medical Re2 " The Toxicity of Industrial Organic " Carbon search Council, Industrial Health Research Board, London, 1937. See also Tetrachloride as an Industrial Hazard " by P. A. Davis. /. Amer. Med. Asso. 103,

961 (1934)-


PHOTOGRAPHIC CHE^VHCALS AND SOLUTIONS

272

Vapors of sulphur dioxide are sometimes given hardener solution for a fixing bath.

The

off

when mixing a

gas on contact with moist

or the respiratory tract, forms sulphurous acid which

is

an

irritant.

air,

The

concentration rarely becomes great enough to be harmful and the use of a fan to

blow the gas away from the top of the tank toward an air open window will usually avoid any trouble, although

outlet duct or an its

vapors are always unpleasant even in small concentrations.

Hydrogen sulphide tion of

when

sodium sulphide

gas

given

is

when making up

off

for sepia toning.

It

There

inhaled in excess produces nausea.

a stock solu-

has an offensive odor, and is

very

little

danger,

however, of getting an excessive dose when working with sulphide, par-

This gas

will fog sensi-

and a toning bath should therefore not be used where unexposed films are handled.

in the vicinity

ticularly

if it is

used

in a well ventilated

room.

tive films,

Ammonia

is

used only occasionally

in

photography and,

centrations, the vapors are quite harmless but,

centrated solution

{

28%

)

low conthe con-

of the gas, care should be exercised, preferably

working near an open window or tion, the gas

in

when handling

air outlet because, in

high concentra-

produces severe smarting of the eyes, nose, and throat.

Formalin consists of a 37 to 37.5% solution of the gas formaldehyde The odor of formalin is very unpleasant to most persons and,

in water.

in contact with the tissues,

which

is

apt to irritate the

Compressed cylinders

formaldehyde

membrane

changed into formic acid

and

throat.^

of gases, such as oxygen, nitrogen, sulphur di-

oxide, etc., are occasionally used

moved

ders should always be

is

of the nose

by photographic concerns.

Such cylin-

or handled in the cradles provided for

them by the companies manufacturing the gas, because if a cylinder is dropped and a valve broken off there is great danger of an explosion or asphyxiation.

In addition to the above mentioned liquids, the following should be

handled with care:

The vapors nitric,

and

of the

common

concentrated acids, such as hydrochloric,

and very

acetic acids are distinctly unpleasant

corrosive.

]Men handling large carboys of acid should wear high rubber boots, rubber aprons, and gloves as a protection against burns in case of accidental breakage.

Suitable goggles should always be

worn

to protect the

eyes against acid burns.

Large carboys of acid should always be 3

H.

Bull.

Phot. 28, 357

W. Haggard,

page 129.

left in

the

wooden

crates in

(1926); also "Noxious Gases" by Y. Henderson and Chemical Catalog Co., N. Y. 1927.


GENERAL SUGGESTIONS AND PRECAUTIONS

273

which they are shipped and the acid emptied out with the aid of a cartilter. These are supplied to fit around the crate and their use

boy

greatly minimizes the possibility of an accident.

The

glass carboys for

such acids should be examined at regular intervals and rejected

show any

Many and

of these acids exert a very corrosive action

clothing.

spilled

Concentrated

on them.

they

all

on wood, metals,

nitric acid, for instance, will ignite rags if

The vapors

boys are commonly handled able at

if

signs of cracking.

of nitric acid are very harmful.

in a particular

times to flush the acid

down

If car-

room, a hose should be avail-

a drain in the event of breakage.

Also, a shower fitted with a quick opening valve should be available for

an employee acid.

Water

to is

run under the best

in the

first

event of accidental splashing of the

aid treatment for acid or alkali burns,

which should be followed by immediate medical treatment.

When

di-

luting sulphuric acid the acid should always be poured slowly into the

water and never the water into the concentrated acid. Bottles of acid should always be stored near the floor.

high shelves, there always

is

If stored

on

the great danger that the acid will be spilled

on the face or body when attempting to remove the bottle from the shelf. Several organic solvents are used by photographers including methyl alcohol, turpentine, acetone, carbon tetrachloride, benzene, ether, chloro-

form, amyl and ethyl acetate, and a few others.

Most

of these solvents

more or less irritating vapors and the vapors from methyl alcohol and benzene are very objectionable and may have harmful effects when breathed for long periods in low concentration. Liquids such as benzene and ether are quite inflammable, and therefore should never be used near open flames or where smoking is allowed. Some organic solvents are particularly unpleasant to work with in confined spaces, and

give off

even though not violently poisonous tend to produce severe headaches

and sometimes nausea.

Carbon tetrachloride has an

effect that

should be mentioned in addi-

tion to the toxicity of its vapors noted previously.

Liquid tetrachloride

hydrolyzes in contact with moisture and liberates hydrochloric acid

which tends to

to attack tender skin tissue.

Constant exposure of the skin

carbon tetrachloride causes drying and cracking of the tissues

which condition the skin Standard practices

in

is

in

very susceptible to irritation.

the handling of acids and alkalis have been

outlined and discussed by the National Safety Council.* 4

Acids and Caustics.

Safety Council, Chicago,

III.

Safe Practices Pamphlet No. 25, published by National


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

274

— The average photographer does not usually have occasion

Solids.

to handle sufficient bulk of

that

is

and dust from them

dry chemicals to introduce a dust problem

Where

at all serious.

large quantities of chemicals are handled

be drawn into the respiratory passages

likely to

is

of the worker, the simple precaution of wearing a dust respirator should

The dust from

be taken.

come dium

offensive

if

may

be-

sodium bisulphite,

so-

the following powdered chemicals

liberated in large quantities:

bisulphate, sodium carbonate, sodium

and potassium hydroxides.

Strong alkalis such as sodium or potassium hydroxide will produce

burns

any

of

if

allowed to enter cracks or open sores on the body.

alkali should not

Solutions

be allowed to dry on the hands repeatedly or

the surface layer of skin will be attacked (see discussion on page

Flash

2

70)

of Photo-

has largely replaced flash powders for flashlight purposes.

flash bulbs

The former

An

— The extensive use

Lamps and Flash Powders. are

much

and smokeless.

safer to use as they are noiseless

occasional bulb shatters, however, so they should not be placed too

close to the face of the subject, a safe distance being 5 or 6 feet.

Flash powders may be divided into two groups: a. pure magnesium powder which is usually blown through a flame, and b. magnesium mixed with some substance rich in oxygen which can be fired either with a cap, electrically, or with a pyrophoric spark.

The second group should

never be used in a blow lamp because of the danger of explosion.

The mixing

or

compounding

of flash

should never be undertaken by a novice. cussion and should be handled or of

powders

moved with

powders are those which are kept

in

is

a skilled art and

IMany powders

two parts

until

ignite

The

great care.

on per-

best types

ready for

firing.

Flash powders should be stored in a dry place, preferably away from the

workroom.

A

small metal cabinet out of doors or on the roof,

equipped with sprinkler heads, represents the best storage condition.

The door

of the cabinet should be kept closed

by means

of a spring so

that in the event of accidental ignition, the products of combustion can

escape freely.

Only enough

for

immediate use should be stored.

Skin Irritations Caused by Developers. pecially during 19 16-18,

the United States

occasionally

and

many impure

— Several years ago,

es-

developing agents were sold

at that time skin irritations

in

were encountered

by photographers which could be traced directly to the use and substitutes. has investigated a number of the derivatives of the phenyl-

of the so-called metol equivalents

Hanzlik

'"

5 The Pharmacology of Some Phcnylcncdiamincs by Hygiene 4, 386 and 448 (1923).

P.

J.

Hanzlik.

/.

Ind.


GENER.\L SUGGESTIONS

AND PRECAUTIONS

enediamines and reported on their toxicity.

one of the

toxic

series

He

275

considered the most

examined was symmetrical dimethyl paraphenyl-

enediamine. The compound paraphenylenediamine as used in many " fine grain " developer formulas is very toxic to many individuals.

Ermen

In 1923

"

isolated symmetrical dimethyl

paraphenylenediamine

samples of metol and proved that the majority of cases of

in certain

dermatitis were a result of the presence of this substance as an impurity.

Since that date, practically

all

aminophenol have improved

the manufacturers of mono-methyl para-

methods

their

of

manufacture

in order to

eliminate the possibility of the formation of any of this constituent.

Cases of skin irritation by metol, therefore, are comparatively un-

known

at the present time but are occasionally encountered.

â&#x20AC;&#x201D;

Diagnosis and Treatment for Skin Irritation from Metol. Usually the trouble commences with a tingling sensation followed by itching and local reddening of the skin. Swelling and the formation of water

occur next, especially in the region of the nails and be-

blisters

tween the

fingers,

and

in severe cases these blisters

large one, encircling the entire hand. tion, the blisters subside,

the patient

with

is

well,

difficulty,

In

all

cases

and there

-it

is

and

though is

if

in

At

combine

to

form one

with careful atten-

this stage,

two weeks the skin begins to

peel,

danger of bacterial infection.

advisable to consult a physician as the condition of

No

the health has an important bearing on disorders of this nature. specific eliminant

in

and

the blisters burst sores are left which heal

appears to have

" been discovered, the usual " cures

the form of ointments serving merely to allay the inflammation.

After the skin has peeled, the parts affected are usually more sensitive to the poison so that special precautions

must be taken

in the future

when

handling this chemical.

Precautions Against Skin Trouble with Metol and Amidol.

â&#x20AC;&#x201D; The simplest precaution

is

to rinse the

hands

in a dilute

acid solution

after using a developer containing these reducing agents or their equivalents.

The

usual acid short stop containing about i\^/c acetic acid rep-

resents a satisfactory acid bath.

Weak

centrated acid to 80 parts of water)

is

hydrochloric acid (i part conalso satisfactory.

several times with plain water, following which soap

Then

rinse

and water may be

used.

Immediate application or dilute acid f

is

of soap

The Preparation of Metol by W.

(1923).

and water before rinsing

in

hot water

not advisable because this tends to precipitate the F. A.

Ermen.

Phot.

J.

63.

in-

(X. S. 47) 223


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

276

soluble base of the developing agent which

and remains

is

sparingly soluble in water

in the skin pores.

Also, developing solutions should never be allowed to dry on the hands

because crystallization of the chemical constituents of the developer (so-

dium

suphite, carbonate, etc.) causes cracking of the skin, thereby per-

mitting easy access of the developing agent to the under layers, therefore facilitating irritation.

A

bath of weak acetic acid (2 to

3%)

should always be within access

darkroom sink (the usual acid short stop is satisfactory) and, before drying the hands which have been wetted with developer, they of the

should be treated as follows:

and then

and water

bathe in the acid bath for 3 to

a.

5

seconds,

wash with warm water. They may then be washed with soap

b.

if

necessary but never before giving treatment

Stains on the hands

may

or b. or both.

a.

be removed by the use of a weak solution of

potassium permanganate (0.5%) acidified with sulphuric acid (about 0.25%). After treatment with this solution, rinse in water and remove

any manganese

stain with

an immersion

5%

in

Then wash

bisulphite.

thoroughly in plain water, dry carefully, and apply a

little

lanoline

cream.

Amidol

may

stains are

be produced

if

more severe than metol, however, and skin troubles strong alkalis, acids, oxidizing agents,

indiscriminately to remove the stains.

with weak acid permanganate

The preceding remarks on summarized as 1.

Most

is

usually effective.

may

be

follows:

cases of skin trouble from metol occur only as a result of the

Many

made

previous to 1925.

cases of skin irritation are the result of using strong alkalis,

acids, or oxidizing agents to clean developer stains off the

not caused by the developer 3.

are used

skin reactions from developers

use of old samples of this developing agent 2.

etc.,

Treatment as described above

Skin irritation from metol

trouble appear

hands and are

itself.

may

be prevented largely

by taking the precaution

to bathe the

if

signs of the

hands

in dilute

acetic acid or hydrochloric acid after handling the developer solution.

This converts any free base of the developing agent into a water soluble salt.

4.

Then wash in warm water and finally in soap and water. Never use soap on the hands directly after handling a developing

solution, without first rinsing thoroughly with hot water. 5.

If irritation persists in spite of the

developer formula

DK-93

p-aminophenol (Kodelon)

above precautions, a

trial of

(Appendix, page 304) containing a is

recommended.

the

salt of


GENERAL SUGGESTIONS AND PRECAUTIONS General Suggestions on

Ways

of

Avoiding Accidents

277

When

Handling Chemicals Keep the chemical storage and mixing rooms Never lift heavy boxes of chemicals. Use a

clean.

truck, traveling skid, or

hoist.

Never take large acid carboys from their crates. Use a carboy tiller when emptying a carboy. Store acids on low shelves near the floor. If acids or alkalis are spilled on the floor, wash them down the drain rapidly with a strong stream of water.

wash them

or body,

off

with water and

If acids are spilled if

on the hands

signs of a burn appear, go at

once to a doctor for treatment.

Sweep

wash up any

or

may

or the dust

solid chemical accidentally

dumped on

the floor

be carried into the air circulation system and spoil sen-

which it comes into contact. Never work with solvents such as carbon tetrachloride, benzene, turpentine, etc., in a closed room. Work near an open window or arrange sitized films with

to

is

have the vapors carried out by means of an exhaust fan. Inflammable liquids should never be opened in rooms where smoking permitted. If any liquids of this type are spilled on the floor while

they are being transported from one room to another, they should be

wiped up at once.

If ignited, the fire will travel

and may cause a

ter-

rible explosion.

Tanks of liquid should always be covered to prevent any contaminaby foreign matter and, in the case of large tanks, to prevent any-

tion

one falling into the tank. Sensitized photographic materials should preferably be stored in a

room

some distance from the chemical

at

storage, mixing, developing, or

toning rooms to avoid possible contamination by gases or chemical dust

suspended

in the air.

All poisonous chemicals should be kept under lock

and key when not

in use.

IMost

all

cases of poisoning, acid burns, asphyxiations,

and explosions and

result from carelessness or the worker's failure to heed warnings

instructions

regarding the approved ways of handling photographic

chemicals. useful hints regarding approved industrial practice are contained in the booklet " Fire Prevention and Safe Practices " distributed

Many

by Eastman Kodak

Stores, Inc.

following bibliography.

Additional references are given in the


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

278

Bibliography on Industrial Poisoning and Hazards "

Health Hazards of the Chemical Industry

" Special Bull.

No. 96,

Dept. of Labor, Albany, N. Y., Nov. 1919. " Industrial Poisons in the

millan Co.,

New

United States

"

by

Alice Hamilton.

Mac-

York, 1925.

" Noxious Gases and the Principles of Respiration Influencing Their Action " by Y. Henderson and H. W. Haggard. The Chemical Catalog

Co., Inc., "

New

York, 1927.

Memoranda

iston's

"

Son

&

of Toxicology "

by M. Trumper.

2nd Edit.

of Labor Statistics " U. S. Dept. of Labor, Government Printing Office, Washington, 1929.

Handbook

491, U.

S.

P. Blak-

Co., Philadelphia, Pa., 1929.

" Industrial Toxicology "

by Alice Hamilton,

New

Bull.

No.

York, Harper

&

Bros., 1934. " Toxicity of Industrial

Organic Solvents

"

Summaries

of published

work, compiled under the direction of the British Medical Research Council

and Industrial Health Research Board.

Office,

London, 1937.

His Majesty's Stationery


CHAPTER XIV APPENDIX

PART The

A.

FORMULARY

following formulas, although those of one manufacturer, repre-

sent typical formulas as used in each branch of the photographic industry in the United States. The numbers given are those used by the Eastman Kodak Company to designate their formulas in their publications. The formulas are arranged in order of their number and are also indexed according to their use. Developer numbers are prefixed by the letter " D "; fixing baths by the letter " F," etc.

From

this

group of formulas,

will give a satisfactory result

Why many

it

is

possible to select a formula which

with any given photographic material.

the Multiplicity of Developing Formulas?

â&#x20AC;&#x201D; Although

developing formulas will give equally good results with different

sensitive materials, certain emulsions require specific formulas in order

optimum

to insure

results, while

different results are

often required

with the same emulsion and these cannot always be obtained by changing the dilution of a particular formula.

There because

is it

duced with

a tendency for pyro to

fall

into disuse as a developing agent

tends to give pyro-stained images which cannot be repro-

Pyro as a de-

sufficiently precise printing characteristics.

veloping agent

is

rapidly being replaced by Elon and hydroquinone.

Pyro, however,

is

very satisfactory for tray development when condi-

tions are favorable for the production of aerial oxidation fog because

pyro It

is

an anti-aerial fogging agent.

has been considered desirable to include both Elon-hydroquinone

and pyro formulas even though, Selection of a Developer,

in

many

cases, they are supplementary.

â&#x20AC;&#x201D; When choosing a developer, the user

should follow the manufacturer's directions whenever possible. realized,

however, that such instructions do not cover

the user must sometimes be confused by the

should not be

difficult

number

formula

is

cases

It is

and that

of formulas.

It

to choose formulas for specific types of work, but

for general applications, the following suggestions

No

all

known

may

prove helpful.

which can be applied with equally satisfactory

and papers. The standard paper developer formula D-72 probably approaches most nearly such an ideal developer, and has been recommended in a limited number of cases for use with negative materials, where rapid development with a fairly high conresults to films, plates,


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

280

trast is desired

On

raphy.

and

such as for some types of copying and for press photog-

the other hand, the contrast negative developers for films

D-19 and D-igb,

plates, formulas

will

papers by diluting the developer 1:1 or 1:2.

with

these formulas

all

when they

work with some grades

of

Best results are secured

are used with the materials for which

See Formula Index, pages 348-357.

they were worked out.

For general tank or tray use, the following formulas

will give satis-

factory results with negative materials:

For low contrast and maximum shadow detail. D-76 DK-50, D-7, and D-6ia For average contrast. D-19 and D-ii For high contrast. For very high contrast. D-8 and D-9 minimum graininess. DK-20 For

Time

— —

of Development.

— The time

gamma

degree of contrast or

of

development determines the

of the negative or positive.

The

actual

density contrast or difference in density between highlight and shadow is

determined both by the brightness contrast of the subject and the

To

degree of development.

obtain a negative having a standard density

contrast, in the case of a subject with a high brightness contrast, a rela-

development

tively short time of

is

necessary, whereas with a flatly

lighted subject, the time of development should be increased.

It is

therefore not possible to give a definite time of development for a given

negative but the range of times indicated represents the average times of

development necessary with average subjects.

Replenishing Solutions for Developers. oper gradually becomes ing agents

less active

due

— During use a

devel-

to the exhaustion of the develop-

and the accumulation of developer reaction products, but the more or less restored by the addition of replenishing so-

activity can be

lutions

which usually contain a high concentration of developing agents

but no bromide.

For tank development, the replenishing formula

is

usually so designed

that the time of development to secure a given degree of contrast

constant when ishing solution.

withdrawn

is

the level of the developer

This

is

is

is

maintained with the replen-

on the assumption that the volume of developer

proportional to the quantity of films developed, and this

condition maintains

if

the films are drained for a constant time.

With a replenished developer, when developing trast, there is some loss of shadow detail but, for loss of detail is negligible.

to a fixed density con-

practical purposes the


FORMULARY

281

DEVELOPERS Three-Solution Pyro Developer Tank

(For General

Stock Solution A

9.8 grams 60.0 ftrams

140

Pyro Potassium Bromide

make Stock Solution B to

Water

Sodium

Metric

Avoirdupois grains

Sodium Bisulphite Water

[D-l]

or Tray Use)

Sulphite, desiccated

2 16

ounces grains

l.I

32

ounces

1.0 liter

32 ounces 3J2 ounces

105.0

ounces ounces

75.0

grams

1.0 liter

grams

C

Stock Solution

Water

32

Sodium Carbonate, desiccated

...

2' 2

.

1.0 liter

grams

Dissolve chemicals in the order given.

For tank, take

part of A,

i

Develop about

water.

For tray, take of water.

12

part of A,

i

Develop about

part of B,

i

C and

part of

i

ii parts

minutes at 65 °F. (i8°C.). part of B,

i

6 minutes at

part of

i

C and

Prepare fresh developer for each batch of

film.

Elon-Pyro Developer Tank

(For General

Stock Solution A Water (about 125° Elon

parts

7

65°F. (i8°C.).

[D-7]

or Tray Use)

Avoirdupois ounces 16

F.) (52° C.)

% M

Sodium Bisulphite Pyro

I

Potassium Bromide Cold water to make

Metric 500.0 cc

ounce ounce ounce

7.5 7.5 30.0 4.2

60 32

grains

32

ounces ounces

150.0

ounces 32 2)^ ounces

75.0

ounces

grams grams grams grams

1.0 liter

Stock Solution B

Water

Sodium

Sulphite, desiccated

Stock Solution

5

1.0 liter

grams

C

Water

Sodium Carbonate, desiccated

....

1.0 liter

grams

Dissolve chemicals in the order given.

For tank, take

i

part of A,

water.

Develop about

be used

2

in the

A

by addition

or 3 weeks

proportion of

i

i

part of B,

part of

i

C and

11 minutes at 65°F. (i8°C.). of fresh developer

part each of A, B, and

C

13 parts of

Developer

may

whenever necessary,

to 4 parts of water.

form of a shallow boat made of Kodaloid or 18-8 or a paraffin paper floated on the solution should be used

floating lid in the

stainless steel

to prevent aerial oxidation.

For water.

tray, take

i

part of A,

i

part of B,

i

part of

Develop about 8 minutes at 65°F. (i8°C.).

C and

8 parts of


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

282

PROCESS FILM AND PLATE DEVELOPERS The

D-g

following Hydroquinone-Caustic Process Developers

will give

very high density and

D-8 and

be found best for line work.

will

Formula D-8 has somewhat better keeping properties in an open tray than D-9 and gives a slightly higher density in a shorter time of development. Both formulas should be used at a temperature of 65°F. (i8°C.), not warmer, and not colder than 55°F. (i3°C.). It is important to wash all negatives very thoroughly before fixing, or stains and dichroic fog will result.

Fix in an acid-hardening fixing bath.

Single Solution Hydroquinone-Caustic Developer

[D-8]

(For High Contrast

on Process Films and

*Water

Sodium Hydroxide

12

(caustic soda) ....

Potassium Bromide Water to make

1

Dissolve chemicals

2

gallon

the order given.

in

parts of stock solution and

2

3.0 liters

360.0 grams 180.0 grams 150.0 grams 120.0 grams 4.0 liters

ounces 6 ounces 5 ounces 4 ounces

Sulphite, desiccated

Hydroquinone

For use, take

Metric

96 ounces

Sodium

about

Plates)

Avoirdupois

Stock Solution

i

part of water.

Develop

minutes at 65 °F. (i8°C.).

This formula

especially

is

recommended

for

making

line

and halftone

screen negatives intended for printing directly on metal.

A

formula which

is

slightly less alkaline

and gives almost as much

density can be obtained by using 3! ounces of sodium hydroxide per gallon of stock solution (112 grams per 4 liters) instead of the quantity

given in the formula.

[D-9]

Two

Solution Hydroquinone-Caustic Process Developer (For Tray Use)

Stock Solution A Water (about 125°

Avoirdupois ounces 16

F.) (52° C.)

% % %

Sodium Bisulphite Hydroquinone Potassium Bromide Water

to

make

32

Metric 500.0 cc 22.5 grams 22.5 grams 22.5 grams

ounce ounce ounce ounces

1.0 liter

Stock Solution B *Cold water 32 ounces Sodium Hydroxide (caustic soda) 1% ounces Dissolve chemicals in the order given. .

*

1.0 liter

52.5

grams

Cold water should always be used when dissolving sodivmi hydro.xide (caustic

soda) because considerable heat boil

.

with violence and

or face.

may

is

evolved.

If hot

cause serious burns

if

water

is

used, the solution will

the alkali spatters on the hands


:

FORMULARY Use equal parts velop about

when mixed and

A

of

A

and B.

Shake bottles well before using.

minutes at 65°F. (i8°C.).

2

therefore

is

283

This developer

will not

not suitable for tank development.

much

developer which gives almost as

be used for tank or tray developing,

is

density, keeps well,

(For

Tank

125° F.) (52° C.)

Sulphite, desiccated

to

make

1.0

ounces

75.0 9.0 25.0 5.0

grains grains grains

130 365 73 32

Sodium Carbonate, desiccated Potassium Bromide

500.0 cc

grains

2} o

Hydroqulnone

Metric

ounces

16 15

Elon

Water

[D-ll]

or Tray Use)

Avoirdupois

Sodium

and can

given below:

Elon-Hydroquinone Developer Water (about

Dekeep

ounces

1 .0

gram grams grams grams grams liter

Dissolve chemicals in the order given.

Use

Develop about

full strength.

minutes

5

in a

tank or 4 minutes

in

a tray at 65°F. (i8°C.).

This formula is useful for general commercial photography and for making halftone screen negatives from which positive transparencies are to be made for dot etching. When great contrast is not desired, dilute the mixed developer with an equal volume of water. Formula D-ii is also recommended for development of lantern slides of line drawings. Use without dilution and develop about 6 minutes in a tank or 5 minutes in a tray at 65°F. (i8°C.).

DEVELOPMENT AT HIGH TEMPERATURES (75° to 90° F.} (24° to 32° C.)

develop films or plates in most developers (except

It is possible to

those which oxidize very rapidly) at temperatures to 75° F.

(24°C.)

by shortening the development time proportionately from that used 65 °F. (i8°C.). solutions

and

if

If

the

it is

at

not possible to control the temperature of the

wash water temperature

is

higher than 75°F. (24°C.)

special developers are required as follows

Tropical Process Developer

[E)-13]

(Para-.\mlnophenol-Hydroqulnone)

Water rabout 125''F.) (52° C.) Para-aminophenol Hydrochloride

Sodium

Sulphite, desiccated

Hydroqulnone

Sodium Carbonate, desiccated

Avoirdupois ounces 24 ..

.

75

grains grains

5.2 52.5 10.5

ounces

52.5

1% ounces 150 IJ^

Metric 750.0 cc

grams grams grams grams grams grams

grains 2.1 30 45.0 1,4 ounces Sulphate, desiccated ounces 1.0 liter 32 Cold water to make Dissolve chemicals in the order given. * If crystalline sodium sulphate is preferred, use i'A ounces per quart (105 grams

Potassium Iodide

Sodium

per liter) of developer.


PHOTOGRAPHIC CHEAHCALS AND SOLUTIONS

284

Use without

Develop 6

dilution.

minutes at 85°F. (29°C.) or

to 7

for proportionately longer times at lower temperatures.

oughly lution

for

30 seconds and immerse

(37% formaldehyde, Then wash

water).

for

diluted

minute,

i

minutes

for 3 i

fix

5%

in

Rinse thorformalin so-

part formaldehyde to 19 parts for 5 to 10

minutes

in

an acid

hardening fixing bath (Formula F-5) and wash for 15 to 20 minutes. It is important to rinse for the time stated after development, otherwise the formalin will soon become discolored with oxidized developer. It is

necessary to remove most of the formalin before fixing, otherwise

the formalin would turn the fixing bath milky and produce dichroic fog.

Kodalk Tropical Developer

[DK-15]

(For General Use with Films

and

Plates)

Avoirdupois

Water (about

125° F.) (52° C.)

Elon

82

Sodium

Cold water to

grains

5.7 90.0 22.5

27 grains 1}^ ounces

45.0

3

make

750.0 cc

ounces ounce

Sulphite, desiccated

Kodalk Potassium Bromide *Sodium Sulphate, desiccated

Metric

ounces

24

%

32

1.9

ounces

grams grams grams grams grams

1.0 liter

Dissolve chemicals in the order given. * If crystalline sodium sulphate is preferred, use 3^ ounces per quart (105 grams per liter) of developer.

Average times of tray development

for roll film, sheet film,

and plates

are as follows:

Time

Temperature 65° 70° 75° 80° 85° 90°

F. F. F. F. F. F.

(18° C.) (21° C.) (24° C.) (26.5° C.) (29.5° C.) (32° C.)

Increase the time given about trast

may

10

8 bVi 5

i% 21^

25%

for

minutes minutes minutes minutes minutes minutes

tank use.

Greater or less con-

be obtained by developing longer or shorter times than those

specified.

A

formula giving

much

may

less contrast

be obtained by

using only 73 grains of Kodalk per 32 ounces of developer (5 grams per liter) instead of the quantities given above. This formula is known as

DK-i5a. Prolonging the development time sive swelling

and softening

at high temperatures, the

is

very undesirable because exces-

of the gelatin will result.

For best results

development time should be as short as pos-

sible.

Formula

DK-15

(18° to 24°C.)

if

will

develop more rapidly when used at 65° to 75 °F.

the sulphate

is

omitted, but

it

should always be used

when working above 75°F. (24°C.). The times should be decreased about 2>:i% when the sulphate is omitted.


FORMULARY An

285

and which gives is Formula

alternative formula which does not contain Elon

results very free

from fog and with a minimum of swelling

D-91, page 304. Warning: It is important to agitate the films or plates when first immersing them in the developer and at intervals during development to avoid streakiness. After development, rinse for i or 2 seconds in water and then immerse for 3 minutes in the tropical hardening bath Formula SB-4, page 308). Omit the water rinse if the film tends to soften but include {

it if

of a

the

possible because

it

helps minimize the tendency for the formation

chromium scum when the alkaline developer on the film reacts with acid chrome alum bath. After hardening, fix for at least 10 minutes

in the

hardening bath (Formula F-5) before transferring to the w^ash

water.

The temperature

of the

wash water should not be over 95 °F.

(35°C.).

Reference should be

made

to

Chapter VIII, page 178,

for a

more com-

plete discussion of handling solutions at high temperatures.

Development of Fine Grain Panchromatic Films at Temperatures Above 75°F. (24°C.) Negatives with low graininess and a maximum of shadow detail on fine grain panchromatic films may be obtained by using D-76 (page 293) which gives lower contrast than either DK-15 or D-91. When working above 75°F. (24°C.) add i^ ounces per quart (45 grams per desiccated sodium sulphate to Formula D-76 and increase the

liter) of

normal development time about 33 7^- An improved ultra-fine grain developer giving a minimum emulsion speed loss and much finer

D-76

grained image than

is

known

as

DK-20.

This formula

is

given

on page 337.

Tank Developer

for

Motion Picture

Positive

Avoirdupois

Water (about

125° F.) (52° C.)

Elon

5

Sodium

ounces

39H pounds pounds 6 18?i pounds

Sulphite, desiccated

Hydroquinone .Sodium Carbonate, desiccated

ounces HH ounces

Potassium Bromide Citric Acid

11

IH pounds

Potassium Metabisulphite Water to make

120

gallons

Film

[D-16]

Metric 500.0 cc 0.31 ftram 39.6 grams 6.0 18.7 0.86

grams grams

0.68

gram gram

1.5 1.0

liter

grams

Dissolve chemicals in the order given.

For large

scale mixing, see suggestions on

Average time of development:

s to

page 126, Chapter VII.

lo minutes at 65°F. (i8°C.).


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

286

This formula

medium

recommended

also

is

or high contrast

is

for negative

development when

required, for development of variable width

sound negatives, and for both variable density and variable width sound prints.

Replenisher for Formula D-16

[D-16R] Water (about

125° F.) (52° C.)

.

.

Sodium

750.0 cc

ounces 350 grains

4 40

Sulphite, desiccated. ...

Hydroquinone

38

.

Citric Acid

11

0.3 ftram

pounds pounds pounds

9

Sodium Carbonate, desiccated ..

Metric

*Avoirdupois

.

Elon

40.0 9.0

38.0

H ounces

0.7

I'a pounds gallons 120

Potassium Metabisulphite Water to make

grams grams grams gram grams

1.5 1.0 liter

Dissolve chemicals in the order given. *

See suggestions on large scale mixing, page 126, Chapter VII.

Add by

tank as needed to

to the

the film.

When added

in this

make up

for the developer carried out

manner, the developer activity

maintained approximately constant with respect to positive

will

be

film.

Contrast Developer

[D-19]

(For Press, Infrared, Metallographic, and Spectrographic Photography)

Stock Solution Water (about 125° Elon

Sodium

Sulphite, desiccated ...

12

.

Hydroquinone

1

Sodium Carbonate, desiccated ... Potassium Bromide

6

2.0 liters 8.8 grams

ounces 360 grains ounce 75 grains ounces 180 grains

300 grains 1 gallon

make

Cold water to

Metric

Avoirdupois 64 ounces 128 grains

F.) (52° C.)

384.0 35.2 192.0 20.0

grams grams grams grams

4.0 liters

Dissolve chemicals in the order given.

Use without

dilution.

Develop

3 to 6 minutes in a tray at

(i8°C.) according to the contrast desired.

65°F.

Increase the time about

25%

for tank development.

I

For infrared landscape photography, dilute as follows: stock solution Develop about 5 minutes in a tray at 65 °F.

part, water 4 parts.

(i8°C.).

This developer

may

where high contrast

[D-19b]

is

also be used for x-ray films

and

in

most cases

desired.

Aero and X-Ray Film Developer (For Tray or

Water (about

125° F.) (52° C.)

Elon

Sodium Sulphite, desiccated Hydroquinone

Sodium Carbonate, desiccated Potassium Bromide Cold water to make

Tank

Use)

Avoirdupois 64 ounces 128 grains 9 ounces 265 grains 1 ounce 75 grains 6 ounces 180 grains 240 grains 1

gallon

Dissolve chemicals in the order given.

Metric 2.0 liters 8.8 grams

288.0 35.2 192.0 16.0

grams grams grams grams

4.0 liters


FORMULARY Develop aero

film about 15 minutes at

287

65°F. (i8^C.)

in a

tank of

fresh developer.

Decrease the development time about (Fahrenheit)

rise in

Develop x-ray This

is

-\

minute

each degree

for

temperature.

film about 5 minutes at 65 °F. (i8°C.) in a tank.

one of the most satisfactory developers available.

Motion Picture Sound Film Negative Developer (For Variable

Avoirdupois

Water (about

750.0 cc

pounds pounds pounds pounds pound

6

Sulphite, desiccated

30

Hydroquinone Kodalk Potassium Bromide Cold water to

Metric

125° F.) (52° C.)

Elon

Sodium

[DK-30]

Width Sound Records)

3

40 1

make

6.0 30.0 3.0

40.0

drams grams grams grams

1.0 gram 1.0 liter

120 gallons

Dissolve chemicals in the order given. *

See suggestions on large scale mixing, page 126, Chapter VII.

Use without

Develop about

dilution.

minutes at 65 °F. (i8°C.)

5

in

a tank of fresh developer.

By

increasing or decreasing the

Kodalk

in the formula,

possible

it is

to a. increase or decrease the contrast obtained in a given time of devel-

opment, or

b.

decrease or increase the time of development required to

obtain a given degree of contrast.

Lantern Slide Developer (For

Stock Solution A Water (about 125°

Sodium

Warm

Avoirdupois F.) (52° C.)

16

Hydroquinone Potassium Bromide Citric Acid

make

Stock Solution B Cold water Sodium Carbonate, desiccated Sodium Hydroxide (caustic soda) Dissolve chemicals

For I

use, take equal parts of

part of

about

5

A and

2

parts of B.

ounces

90 grains 100 grains 50 grains 10 grains 32 ounces

Sulphite, desiccated

Cold water to

32 ounces 1

...

in

A and Stir

minutes at 70'F. (2i''C.).

[D-32]

Black Tones)

ounce

60 grains

Metric 500.0 cc 6.3 7.0 3.5 0.7

grams grams grams gram

1.0 liter

1.0 liter

30.0 4.2

grams grams

the order given.

B.

For

still

warmer

tones, take

thoroughly before use.

Develop


PHOTOGRAPHIC CHEMICALS AXD SOLUTIONS

288

*

Lantern Slide Developer

[D-34]

(For Cold Black Tones)

Stock Solution A Water (about 125° Elon

Sodium

16

ounces

60

grains

H

Sulphite, desiccated

Hydroquinone Cold water to

Metric

Avoirdupois F.) (52° C.)

Ji

make

32

500.0 cc 4.2 15.0 15.0

ounce ounce ounces

grams grams grams

1.0 liter

Stock Solution B \\

ater

32

Sodium Carbonate, desiccated

....

}-i

Potassium Bromide

ounces ounce

1.0 liter

15.0

grains

30

2.1

grams grams

Dissolve chemicals in the order given. *

Formula D--2

For

also

recommended

A

use, take equal parts of

This formula

7o°F. (2i°C.). contrast,

A

is

Formula D-ii

is

for lantern slides, see page 292.

Develop i^

and B.

may

to 3

minutes at

be used for line work; for

maximum

recommended. (Formula R-4, page

brief treatment with dilute Farmer's reducer

319) after fixing and washing will give added brilliance to the For softer tones, take equal parts of A, B, and water.

slide.

Elon-Hydrcquinone-Kodalk Developer

[DK-40]

Motion Picture

(For

Positive Film)

Metric

*Avoirdupois

Water (about

125° F.) (52° C.)

Elon

1

Sodium

Sulphite, desiccated

30 4 20

Hydroquinone Kodalk Potassium Bromide Cold water to

750.0 cc

pound pounds pounds pounds

grams

4.0 grams 20.0 grams 0.5 gram 1.0 liter

8 ounces 120 gallons

make

gram

1.0

30.0

Dissolve chemicals in the order given. *

See suggestions on large scale mixing, page 126, Chapter VII.

Use without

Develop

dilution.

5 to 7

minutes at 65 'F. (i8°C.)

a tank of fresh developer according to the contrast desired.

mula

By a. to

is

This

in

for-

also satisfactory for use with Duplicating Positive film.

increasing or decreasing the

Kodalk

in the

formula,

it is

possible

increase or decrease the contrast obtained in a given time of de-

velopment, or

b. to

decrease or increase the time of development with-

out affecting the contrast.

[DK-50]

Elon-Hydroquinone- Kodalk Developer (For

Roll Films, Film Packs Professional Films and Plates)

Normal Contrast on

Stock Solution Water (about 125° Elon

Sodium

Avoirdupois F.) (52°C.) ...

Sulphite, desiccated

Hydroquinone Kodalk Potassium Bromide Cold water to

make

...

64 ounces 145 grains 4 ounces 145 grains 1 ounce 145 grains 29 grains 1

gallon

Dissolve chemicals in the order given.

and Metric 2.0 liters 10.0 grams

120.0 10.0 40.0

grams grams grams grams

2.0 4.0 liters


.

FORMULARY For tank use I

65"F. (i8°C.)

with professional films and plates, take

for portraiture

part stock solution and

289

i

part water and develop 8 to 12 minutes at

in the fresh

developer according to the contrast desired.

For commercial photography use without dilution and develop in a tank 6 to 10 minutes at 65T. ( i8°C.) according to the contrast desired. For tray, use without dilution

and develop 4

minutes at 65

to 6

These development times are satisfactory

for

"^F.

(18 '€.).

copy negatives and trans-

parencies.

Develop 65°F.

roll films

(i8°C.)

and panchromatic

packs about 10 minutes at This developer

machine development

satisfactory for deep tank or

Develop orthochromatic

plants.

film

the undiluted fresh developer.

in

packs about lo^c

film

is

in photofinishing

longer than

roll films.

Greater or

less contrast

may

be obtained by developing longer or

shorter times than those indicated.

By it is

increasing or decreasing the quantity of

Kodalk

in the formula,

possible a. to increase or decrease the contrast obtained in a given

time of development, or

ment without

b. to

decrease or increase the time of develop-

affecting the contrast.

[DK-50R]

Replenisher Solution (For Use with Formulas

DK-50 and DK-60) Avoirdupois

Water

(125° F.; (52° C.)

Sodium

Sulphite, desiccated

.

Hydroquinone Kodalk Cold water to

grains

ounces ounce 145 grains ounces

1

5K

make

Metric

ounces

96 290 4

Elon

gallon

1

3.0 20.0 120.0 40.0 160.0 4.0

liters

ftrams ftrams

grams grams liters

Dissolve chemicals in the order given.

For sheet films and plates, dilute with an equal part of water and add to the

For

tank as needed to maintain the level of the solution. roll films

and

film packs, use without dilution

and add

to the

tank

as needed to maintain the level of the solution.

When discard to

used with Formula

some

DK-60, page

of the used developer

290,

when adding

it

may

be necessary to

the replenisher in order

maintain an approximately constant developing time.*

Amidol Developer Stock Solution Water fabout 125°

Sodium

for

Bromide Papers Avoirdupois

F.) (52° C.)

Sulphite, desiccated

24 4

ounces ounces

750.0 cc 120.0 grams

Di-aminophenol Ilydrochlorlde (Amidol)

Cold water to

IJi

make

32

ounces ounces

[D-51]

Metric

37.5

grams

1.0 liter

Di.ssolve chemicals in the order given.

See comment on the use of the Special Kodalk Replenisher for use with DK-60, as given on page 290. *


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

290

For use take 6 ounces (i8o cc) stock solution, | dram (3 cc)

10%

potassium bromide solution, and 24 ounces (750 cc) of water. Develop i^ to 3 minutes at 7o°F. (2i°C.). Use at once after dilution with water as the solution oxidizes rapidly on exposure to air.

Portrait Paper Developer

[D-52]

Stock Solution Water (about 125° Elon

Sodium

Avoirdupois F.) (52° C.)

22

Sulphite, desiccated

1.5

ounce ounce

22

grains

1.5

32

ounces

1

Yi

make

grains

grains

90

Sodium Carbonate, desiccated Potassium Bromide

Metric 500.0 cc 22.5 6.3 15.0

J^

Hydroquinone Cold water to

ounces

16

grams grams grams grams grams

.0 liter

Dissolve chemicals in the order given.

For professional contact papers, use stock solution I

i

part, water,

part.

For professional enlarging papers and bromide papers, use

full

strength

solution.

Develop Note

may

:

papers not

all

than \\ minutes at 7o°F. (2i°C.).

less

This developer contains the

be added

warmer tones are

if

minimum

More bromide

quantity of bromide.

desired.

Rapid Machine Developer

[DK-60] (For Rapid

Machine Development

of Roll Films

and Film Packs)

Avoirdupois

Water (about

125° F.) (52°

C).

Elon

Sodium

Sulphite, desiccated

.

.

5

290

make

10

2.5

30.0

3M ounces 1

pound

Metric 500.0 cc

3J^ ounces 2J^ pounds

Hydroquinone Kodalk Potassium Bromide Cold water to

gallons

IOI/2

ounces

grains gallons

grams grams

2.5 grams 20.0 grams 0.5 gram 1.0 liter

Dissolve chemicals in the order given.

Develop

roll films

65°F. (i8°C.)

and panchromatic

in the fresh developer.

film

packs about

7

minutes at

Develop orthochromatic

film

20% longer than roll film. Formula DK-50R, page 289, is recommended as a replenisher for DK-60 developer. Eastman Special Kodalk Replenisher * may also packs for

be used and

will

maintain the developing time approximately constant

provided about 6 gallons of developer are removed per 1000

rolls of

film developed.

Greater or less contrast

may

shorter time than indicated. *

Supplied

in

packages.

be obtained by developing a longer or


FORMULARY By it

increasing or decreasing the quantity of

possible

is

291

time of development, or

ment without

The

Kodalk

in the

formula,

increase or decrease the contrast obtained in a given

a. to

b. to

decrease or increase the time of develop-

affecting the contrast.

following table gives the times of tank development for amateur

roll films at

65°F. (i8-C.)

same quantity Formulas DK-50 and ing the

for equal contrast

with a developer contain-

of developing agents, sulphite,

DK-60

Time

Kodalk Concentration Per GaUon grains

290 1

2

(DK-60)

2

4

(Saturation Limit)

.

5M

.

Tank Develop-

of

ment*

in the Developer

(DK-50)

and bromide as

with varying quantities of Kodalk.

65°F.(18°C.)

Per Liter

ounce 145 grains ounces ounces 290 grains ounces ounces

5.0 10.0 15.0 20.0 30.0 40.0

grams grams grams grams grams grams

15 10

%% 7 b]4,

5

minutes minutes minutes minutes minutes minutes

These times give approximately equal contrast.

*

These concentrations of Kodalk cover the range of development time In the most concentrated formula

considered to be of practical interest.

(5^ ounces of Kodalk per gallon) (40 grams per

liter)

the concentra-

same as that used for the replenisher solution, DK-50R. With the more concentrated solutions, it will be necessary usually to discard some of the used developer in the tank when adding the replention

is

isher

the

(DK-50R)

in order to

maintain an approximately constant de-

veloping time.

When

temperature control

must be varied

to

is

not possible, the time of development

maintain equal contrasts in accordance with the

fol-

lowing table:

Time-Temperature Table

for Fresh Developers

for Roll Films To Maintain Equal Contrasts 55°F. (12°C.) 60° F. (15° C.) 65° F. (18° C.) Standard. 70° F. (21° C.) 75° F. (24° C.)

Note:

DK-60

DK-50

Temperature

.

.

14 12 10 8 7

minutes minutes minutes minutes minutes

If a different standard time

10 9 7 6 5 is

used

minutes minutes minutes minutes minutes tlian

20%

for tray development.

26 20 15 12

D-76 D minutes minutes minutes minutes minutes

76 (Kodalk)* 29 24 20 16 13

minutes minutes minutes minutes minutes

given in the above table, the times

at the other temperatures should be varied proportionately.

about

33

Decrease the times given

Increase the times given about

20%

for ortho-

chromatic film packs. * A developer having the same time of development at 6s°F. (i8°C.) may be obtained by substituting an equal quantity of Kodalk for the borax in D-76. The temperature coefficient of the resulting developer differs slightly from that of regular

D-76

as

shown by the

table under

D-76 (Kodalk).


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

292

Elon-Hydroquinone Developer

[D-61a]

Tank

or Tray Use with Professional Films

Stock Solution

Avoirdupois

(For

Water

and

Metric

64 ounces 45 grains

Elon

Sodium Sulphite, desiccated Sodium Bisulphite Hydroquinone

Sodium Carbonate,

desiccated

Potassium Bromide Cold water to make

3

30 85 165 24 32

Plates)

500.0 cc 3.1

ounces

90.0

grains grains grains grains

2.1

5.9 11.5

grams grams grams grams grams grams

1.7 1.0 liter

ounces

Dissolve chemicals in the order given.

For tank, take

i

part stock solution and 3 parts water. Develop about Add stock solution (diluted 1:3) at in-

14 minutes at 65° F. (i8°C.).

below to main-

tervals to maintain the volume, or the replenisher given tain the strength of the solution.

For tray take 7

i

part stock solution and

i

Develop about

part water.

minutes at 65°F. (i8°C.).

Replenisher for Tank Dilution D-61a

[D-61R]

Stock Solution A Water (about 125° Elon

F.) (52° C.)

Sodium Sulphite, desiccated Sodium Bisulphite Hydroquinone Potassium Bromide Cold water to

make B

to

make

3.0 liters 5.9 grams

grains

6 55 170 45 1}4

ounces

180.0

grains grains grains gallons

3.8 11.9

8

ounces ounces

240.0

Stock Solution Sodium Carbonate, desiccated ....

Water

Metric

Avoirdupois ounces

96 85

64

grams grams grams grams

3.1 6.0 liters

grams

2.0 liters

Dissolve chemicals in the order given.

For use take as needed.

Do

A and A and B

3 parts of

not mix

i

part of

B and add

to the tank developer

until ready to use.

Universal Paper Developer

[D-72] (For

Amateur Contact Prints and Enlargements)

Stock Solution Water (about 125° F.) Elon

Sodium

Avoirdupois (52° C.)

Sulphite, desiccated

Hydroquinone Sodium Carbonate, desiccated Potassium Bromide Water to make

16

ounces

45

grains

1}4 ounces grains 175 2}4 ounces 27 grains

32

ounces

Metric 500.0 cc 3.1

45.0 12.0 67.5

grams grams grams grams grams

1.9 1.0 liter

Dissolve chemicals in the order given.

For chloride papers take stock solution

i

part, water 2 parts.

Develop

i

part, water 4 parts.

Develop

45 seconds at 7o°F. (2i°C.).

For bromide papers take stock solution

not less than i^ minutes at 70°F. (2i°C.).


.

.

FORMULARY For lantern I

slides take stock solution

minutes at 7o°F. (2i°C.).

to 2

For

for less contrast, 1:4.

i

293

part, water 2 parts.

Develop

For greater contrast dilute 1:1 and

line drawings.

Formula D-i

i

is

recommended

(page 283).

This formula velop about

For

is

less

recommended

also

For average

tives.

development of press nega-

for the

use, take stock solution

minutes

part, water

i

i

part.

De-

tank or 4 minutes in a tray at 65°F. (i8°C.). 5 contrast, dilute 1:2. For greater contrast, use full strength.

Greater or

in a

less contrast

may

also be obtained

by developing longer or

shorter times than those indicated.

Paper Developer for Blue-Black Tones

[D-73]

(For use with Chloride Papers)

Stock Solution Water about Elon

Sodium

Metric

Avoirdupois (125° F.) {52°C.)..

16

40

Sulphite, desiccated

.

Hydroquinone

ounces

500.0 cc

grains

1

ounce

155

grains

140 grains

2^ ounces

Sodium Carbonate, desiccated Potassium Bromide Water to make

12

grains

32

ounces

2.8 40.0 10.8 75.0 0.8

grams grams grams grams

gram

1.0 liter

Dissolve chemicals in the order given.

For use take stock solution

Develop

for

i

part, water 2 parts.

45 seconds at 7o°F. (2i°C.).

Elon-Hydroquinone-Borax Developer (For

[D-76]

Amateur, Professional, Aero and Motion Picture Negatives on Panchromatic Materials and for Variable Density Sound Records)

Water (about

125° F.) (52°

C

)..

Elon

— 2

Sodium Sulphite, Hydroquinone

desiccated.

5

Borax, granular

Water to make For small

100 2

Metric

Avoirdupois

pounds pounds pounds pounds

96 116 1314 290 116

120 gallons

1

ounces

750.0 cc

grains

ounces

2.0

100.0

grains grains gallon

grams grams

5.0 grams 2.0 grams 1.0 liter

scale use, dissolve the chemicals in the order given.

Develop amateur

roll films

and aero

films about 20 minutes in a tank

or 16 minutes in a tray of fresh developer at 65°F. (i8°C.).

Develop professional 65°F.

(

the time about fine grain

A

films

and plates 10

to 25

minutes

in a

tank at

For tray use, decrease This developer gives greatest shadow detail on

i8°C.) according to the contrast desired.

20%.

panchromatic

films.

working developer can be obtained by increasing the quantity of borax as shown in the following table. A still more active developer can be obtained by replacing the borax by Kodalk. When the faster


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

294

D-76

regular quantity of borax in

Kodalk [D-76 (Kodalk)J, the

replaced by an equal quantity of

is

resulting formula has similar properties

but the activity increases proportionately more as the quantity of Kodalk is

as

increased compared with an equal increase in the borax concentration

shown below. of Tank Development of Films or Plates for Equal Contrast with Varying Quantities of Granular Borax in D-76 and Kodalk in D-76 (Without Borax) [D-76]

Times

Borax Concentration Per Gallon Avoirdupois 116 grains

(Regular)

(5X)

1

2 2

X)

(10

Development

Per Liter Metric

ounce 145 grains. ounces ounces 290 grains

.

.

.

.

2.0 10.0 15.0 20.0

Time

grams grams grams grams

20 15 12}^ 10

minutes minutes minutes minutes

[D-76 (Kodalk)] (Borax replaced by Kodalk)

Kodalk Concentration Per Gallon Avoirdupois 116 grains 290 grains 1 ounce 145 grains 2 ounces 290 grains

(Regular)

X)

(21^

(5X) (lOX)

10.0 20.0

.

The formula containing tration represents the

The

Per Liter Metric ^Ticm^ 2.0 5.0

lo times

maximum

grams grams grams grams

(loX)

Development

Time 20 10

7H 5

the original alkali concen-

practical concentration for use.

contrast obtained at 65°F. in 20 minutes (tank) in

(Kodalk)

DK-50

will

minutes minutes minutes minutes

D-76

or

D-76

be slightly lower than that obtained in 10 minutes in

or 7 minutes in

DK-60, but

development of miniature negatives

this is considered desirable for the

for

which D-76 and D-76 (Kodalk)

are especially suitable.

When

temperature control

must be varied

is

not possible, the time of development

to maintain equal contrasts in accordance with the table

on page 291. Directions for Large Scale Mixing: First dissolve the Elon in a small

volume

of water (about i25°F.)

Then

tank.

(52°C.) and add the solution to the

dissolve approximately one-quarter of the sulphite sepa-

rately in hot water (about i6o°F.)

(7i°C.) and add the hydroquinone

with stirring until completely dissolved.

Now

Add

this solution to the tank.

dissolve the remainder of the sulphite in hot water, add the borax,

and when dissolved, pour the entire solution into the tank and dilute to the required volume with cold water. Average development time for panchromatic motion picture negative film

is

8 to 12 minutes at 65°F. (i8°C.) in the fresh developer according


to the contrast desired.

FORMULARY

295

The developer tank

usually becomes coated with

The developer

a thin white deposit of silver but this will do no harm.

may become

muddy due

slightly

loidal silver but

it is

to the

formation of a suspension of col-

harmless and can be ignored.

For duplicate negative

average time of development

film,

is

6 to 9

minutes at 65°F. (iS'^C).

Normal

D-76

contrast of negatives developed in

is

low

(gamma

=

0.5 to i.o).

Replenisher Solution (For

Tank Use with Formula

[D-76R]

D-76)

Avoirdupois

Water (about

125° F.) (52°

C).

.

Elon

Sodium

Sulphite, desiccated

Metric

96 ounces 175 grains 13J4 ounces

.

....

3.0 liters 12.0 grams

400.0

Hydroquinone

1

*Borax, granular

2

ounce ounces 290 grains

1

gallon

Water

to

make

.^0.0

80.0

grams grams grams

4.0 liters

Dissolve chemicals in the order given.

Discard some developer before adding replenisher.

*

Use the replenisher without the level of the solution.

times as great

is

required,

mula D-76R

is

of

substituted for borax in Formula

it is

to

maintain

at least five

D-76 and a

replen-

necessary to substitute Kodalk for borax in For-

as follows:

D-76 (Kodalk) ^

'

Borax Replaced by Kodalk) Per Liter Per Gallon 2.0 grams 116 grains 5.0 grams 290 grains 10.0 grams 1 ounce 145 grains 20.0 grams 2 ounces 290 grains *

and add to the tank Formula D-76 will be

dilution life

this replenisher is used.

if

When Kodalk isher

The

^^ ^ ^ ^^J"® Development

D-76R (Kodalk)

(Tank)

(Borax Replaced by Kodalk) Per Liter Per Gallon

20 10 7}/^

5

minutes minutes minutes minutes

^

7.5

20.0 40.0 *40.0

grams grams grams grams

1

2

5 5

'

ounce ounces 290 grains ounces 145 grains ounces 145 grains

Discard some developer before adding replenisher.

FINE GRAIN DEVELOPMENT The

introduction of small cameras taking small negatives has stimu-

lated interest in developers

The

which give images with a minimum graininess.

relative value of developers with regard to their ability to give

fine grain

images can only be measured provided a comparison

is

made

of images which have a. equal densities, and h. which received equal de-

grees of development.*

Most * "

fine grain

developers produce

The Maintenance

warm

of Negative Quality " by J.

800-804, 874-880, (1937).

toned images the effective I.

Crabtree.

Amer. Phot.

31,


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

296

photographic printing density of which so that,

if

compared with black

is

greater than the visual density

or neutral images obtained in regular

developers, fine grained negatives should be slightly underdeveloped in

order to obtain matched prints.

When comparing

developers for

graininess, therefore, the negatives should be developed for times such

that

matched prints are obtained when the prints (on a given paper)

are developed for equal times.

Diminished graininess tive slightly

is

usually obtained by underdeveloping a nega-

because the graininess of a negative having a given density

increases as the development factor or

gamma

increases.

Development

should not be too short, however, because any scratches or abrasions on the negative will then

At the present

show up

to a greater extent in the finished print.

state of our knowledge,

any

duces graininess at the expense of some loss

in

fine grain

developer re-

emulsion speed.

Even

with the most satisfactory fine grain developers, this speed loss varies

from 25

to

50%

but

it

should be remembered that a

25%

speed

loss

is

only just perceptible in the negative.

In most cases,

if

the alkalinity of a given line grain developer

creased so as to speed up development, graininess

no ultra rapid

fine grain

is

is in-

increased so that

developers are available at present.

Of the common developing

agents,

paraphenylenediamine and

its

analogues have the property of giving fine grained images but with

some speed

loss.

phenylenediamine

A

formula containing 10 grams (145 grains) of paratogether with 100 grams (3 ounces, 145

(base)

grains) of sodium sulphite (desiccated) per liter (32 ounces)

factory as any of the properties as

(page 337).

many

is

as satis-

published formulas and has the following

compared with D-76 and the

fine grain

developer

DK-20


.

FORMULARY

297

There is very little difference in the graininess produced by developers other than the recognized " fine grain '" developers when images are compared at

equal densities,

a.

sion speeds.

It is

b.

equal gammas, and

c.

equal effective emul-

generally possible to diminish the graininess attained

with any developer by adding a speed reducing addition agent such as

potassium bromide or other anti-fogging compound, but the graininess reduction

DK-20

usually not so great as that obtained with

is

DK-20. Formula

a fme grain developer having good keeping properties,

is

reasonable short development time.

minimum

The emulsion speed

and a

loss is also a

(see page 337).

Low and Normal Contrast (For Photomicrojiraphy, Metallography,

Developer

Avoirdupois

Water (about

125° F.) (52° C.)

Sodium

Sulphite, desiccated

Potassium

Iodide,

grains

13'4'

Hydroquinone

1%

tPotassium Bromide, Cold water to make

solution solution

2. 5^7

ounces

10

dram drams

1

gallon

1

3.0 liters 8.0 ftrams

400.0

grams

20.0 grams 8.0 grams 4.0 cc 40.0 cc 4.0 liters

grains grains

290 116

Borax, granular

Metric

ounces

96 116

Elon

[D-76c]

and Spectroscopy)

Dissolve chemicals in the order given. *

A 1%

grams)

solution of potassium iodide is prepared by dissolving 44 grains (3 few ounces (cc) of water and adding water to make 10 ounces (300 cc.)

in a

of solution. t

A 2j^%

grams)

in a

solution of potassium bromide is prepared by dissolving ^ ounce (7.5 few ounces (cc) of water and adding water to make 10 ounces (300 cc)

of solution.

Use without dilution. Develop in a tray about 5 minutes for low conand 6^ minutes for normal contrast at 65°F. (i8°C.). For tank development, increase the times given by about 25%. For high and extreme contrast photomicrography, use Formula D-19 trast

given on page 286.

Buffered Borax Negative Developer (For Motion Picture Negatives

Avoirdupois

Water (about

125° F.) (52° C.)

Sulphite, desiccated

2

2.0

100

100.0

Hydroquinone Borax, granular Boric Acid

Water *

to

make

Crystalline boric acid

slowly, and

its

5.0 8.0 8.0

120 gallons

should

be used.

Metric 7.50.0

pounds pounds 5 pounds 8 pounds 8 pounds

Elon

Sodium

[D-76d]

and Variable Density Sound Records)

Powdered

cc

grams grams grams grams grams

1.0 liter

boric

acid

dissolves

very

use should be avoided.

Directions for Use: see mixing directions given for Formula D-76, page 294. Use without dilution. Develop 10 to 25 minutes at 65 °F.

(i8°C.) according to the contrast desired.


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

298

This developer trast.

particularly useful for obtaining images of low con-

is

contrast can be obtained

With non-buffered developers low

dilution but the exhaustion life of the buffered developer above

is

by

greater

D-76 diluted to give the same contrast in the same time. With a ratio of 8 grams borax to 8 grams boric acid, the rate of development is unchanged from that of D-76. By increasing the quanthan that of

tity of

borax with a corresponding decrease

development rate

increased.

is

By

in the boric acid content, the

decreasing the borax and increasing

the boric acid proportionately, the development rate

is

decreased.

mixed sample of the Buffered Borax

Note: The (Formula D-76d) may be controlled by adding 15 grains bromide per gallon (0.25 gram per liter) of the mixed developer. slight initial fog of a freshly

veloper

of

de-

potassium

Glycin Negative Developer

[D-78]

Metric

*Avoirdupois

Water

Sodium

Sulphite, desiccated

Glycin (Athenon) Sodium Carbonate, desiccated

Water

make

to

80 gallons

750.0 cc

3 pounds 3 pounds 6 pounds 120 gallons

3.0 3.0 6.0

grams grams grams

1.0 liter

Dissolve chemicals in the order given.

Average time of development: 15

minutes at65°F. (i8°C.).

to 25

Pyro Tank Developer

[D-79]

(For Negative

Motion Picture Film) Metric

Avoirdupois

Water

Sodium

25

Sulphite, desiccated

Sodium Carbonate, desiccated Potassium Bromide to

2.5 grams 5.0 grams 0.5 gram 1.0 liter

2H pounds

Pyro

Water

pounds

750.0 cc 25.0 grams

make

5

pounds

8 120

ounces gallons

Dissolve chemicals in the order given.

Average time of development: 9 to 12 minutes at 65°F. (i8°C.). This solution oxidizes rapidly and should therefore be used within one hour after mixing.

[D-8O]

Motion Picture Negative Film Developer (For Use with Reel Developing Outfits)

Avoirdupois 125° F.) (52° C.)

Sulphite, desiccated

100

Water (about

5

pounds pounds pounds pounds pounds

120

gallons

Elon

Sodium

2}'2

Hydroquinone

10

tPotassium Carbonate, desiccated .. Potassium Bromide Water to make

50

Metric 750.0 cc 2.5

100.0 10.0 50.0

grams grams grams grams grams

5.0 1.0 liter

Dissolve chemicals in the order given.

Average time of development: 6 * t

to 20

minutes at 65°F. (i8°C.).

See suggestions on large scale mixing, page 126, Chapter VII. See next formula.


FORMULARY

299

Motion Picture Positive Developer

[D-81]

(For Use with Reel Developinft Outfits)

Water (about Elon

Sodium

Sulphite, desiccated

Avoirdupois

125° F.) (52" C.) ..

.

Hydroquinone tPotassium Carbonate Potassium Bromide Water to malce

Metric 750.0 cc

8 ounces 100 pounds 10

100 3

pounds pounds pounds

li

ounces

120 gallons

0.5 t^ram 100.0 grams 10.0 lirams 100.0 grams 3.8 grams 1.0 liter

Dissolve chemicals in the order Kiveii.

Average time of development: 4

minutes at 65' F. (i8°C.).

to 10

*

See suggestions on large scale mixing, page 126, Chapter VII. t An equal weight of sodium carbonate may be used but since potassium carbonate is deliquescent any developer which is splashed on the floor does not dry out and becomes a source of harmful chemical du.st.

Maximum (For Use with

Energy Developer Metric

Avoirdupois

Water (about

Wood

125° F.) (52° C.)

24

Alcohol

l)-2

Elon

ounces ounces

750.0 cc 48.0 cc

grains

200

Sodium

1% ounces

Sulphite, desiccated

Hydroquinone

grains grains grains

200 125 125 32

Sodium Hydroxide (Caustic Soda) .. Potassium Bromide Cold water to make ounces Dissolve chemicals in the order given. .

Use without If

wood

dilution.

Develop 4

alcohol

is

minutes

to 5

The prepared developer does

(i8°C.).

[D-82]

Extreme Underexposures)

14.0 52.5 14.0 8.8 8.8

grams grams grams grams grams

1.0 liter

in a tray at

65°F.

not keep more than a few days.

not added and the developer

is

diluted, the solution

is

not as active as in the concentrated form.

Kodalith Negative Film, Plate, or Paper Developer

[D-85]

(For Line or Halftone Negatives of Extreme Contrast)

Water about

Sodium

2.0 liters

120.0 grams 30.0 grams 10.5 grams 30.0 grams 90.0 grams 6.3 grams 4.0 liters

4 ounces

Sulphite, desiccated

Paraformaldehyde Potassium Metabisulphite

1

ounce

150 grains

Boric Acid, crystals

1

Hydroquinone Potassium Bromide Cold water to

Metric

Avoirdupois 64 ounces

90° F.) (32° C.)

3

ounce ounces

90 grains 1 gallon

make

Dissolve chemicals in the order given.

The mixed pered until

solution should be added to a bottle and kept tightly stop-

it is

used.

Before pouring into a tray, the solution should be

brought to a temperature of 65°F. (i8°C.).

removed from the

is

pouring

into a bottle of smaller size,

tightly.

it

If

only a portion of the

bottle, the balance should

developer

be saved by

which should then be stoppered


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

300

Allow the developer

to

stand about two hours after mixing.

Average time of development: i^

to 2

minutes for

and With a

line negatives

not over 2\ minutes at 65°F. (i8°C.) for halftone negatives.

correctly timed exposure, the image should appear in about 45 seconds.

A

longer time of appearance indicates underexposure

;

a shorter time in-

dicates overexposure.

This formula when used with Kodalith emulsions has the property of giving extreme contrast in the low densities which insures clean dot for-

mation

in

erties for

A

This developer retains

halftone negatives.

about one month

if

much

developer having similar characteristics and

properties as a stock solution

[D-85b]

Two

its

original prop-

stored in a tightly stoppered bottle. better keeping

the following:

is

Solution Kodalith Negative Film, Plate, or Paper Developer

(For Line or Halftone Negatives of

Stock Solution A Water (about 1 25° F.

)

(52° C.

64 ounces 4 ounces

)

Sodium Sulphite, desiccated Boric Acid, crystals

1

Hydroquinone Potassium Bromide Cold water to

Extreme Contrast)

Avoirdupois

3

120.0 30.0 90.0 6.3

ounce ounces

90 grains 96 ounces

make B (Keep

Metric 2.0 liters

grams grams grams grams

3.0 liters

Stock Solution in a well-stoppered brown bottle) Water (about 90° F.) (32° C.) 24 ounces 750.0 cc Potassium Metabisulphite 10.5 grams 150 grains

Sodium

Sulphite, desiccated

15 grains

Paraformaldehyde *Phenosafranine (1 1000 solution) Cold water to make :

Dissolve chemicals * I

in

.

.

1

ounce

5

drams

gram

1.0

30.0 grams 20.0 cc

32 ounces

1.0 liter

each solution in the order given.

To prepare a

liter

i :iooo solution, dissolve i gram (15 grains) of phenosafranine in (32 ounces) of distilled water at i25°F. (52°C.). Allow to cool before use.

For use add inspection for

i

part of Solution

i-}

to 2

B

minutes for

for halftone negatives at

Develop by

to 3 parts of Solution A. line negatives or not over

65°F. (i8°C.).

With

2^ minutes

correct exposures the

flash up in about 45 seconds. A yellow or orange safelight be used after development has progressed for jo seconds. The

image should

may

stock solutions keep satisfactorily for several months.

[D-87]

Pyro Contrast Developer for Aero Films (For General Use at Normal Temperatures) 65° F. to 70° F. (18° C. to 21° C.)

Avoirdupois

Sodium Sulphite, desiccated Sodium Carbonate, desiccated Potassium Bromide Potassium Metabisulphite Pyro Water to make

1 1

ounce 60 grains ounce 125 grains

73 grains 57 grains 165 grains 1

gallon

Metric 34.4 38.4 5.0

grams grams grams grams grams

4.0 11.6 4.0 liters


FORMULARY

301

Directions: This developer oxidizes rapidly, so that the pyro should

be added just before use.

and add

to the tank.

Dissolve the sulphite, carbonate, and bromide

Dissolve the nietabisulphite separately in a small

When

volume of water; then add the pyro.

ready to develop, add the

make up

metabisulphite-pyro solution to the tank and

is

to

volume with

Develop about 30 minutes at 65째F. (i8째C.).

water.

Xotc: Because of the comparatively short keeping properties of this developer, when developing each roll of film.

it

desirable to use a fresh solution

When mended

the use of pyro

staining, 2. keeps well

not preferred, Formula

is

page 286).

(see

D-igb

is

has the following advantages:

It

and may be used several times,

3.

recomnon-

i.

works

satis-

factorily at high temperatures.

DIRECT REVERSAL PROCESS ON PAPER The times

required for each chemical treatment of the exposed paper

in the reversal printing process are as follows: 1.

Development

3.

Clearing

4.

Redevelopment

(45 seconds- 1 minute) 2.

(30 seconds)

Bleach (30 seconds) 5.

(30 seconds)

Fixation

(if

desired, but not necessary)

(30 seconds) necessary to wash the prints well in running water for at least

It is

redeveloper

is

used,

it is

Where

the

recommended

necessary to expose the paper to

artificial light

15 seconds between the different solutions.

If convenient, the white light

or daylight before redevelopment.

can

be turned on as soon as the prints are placed in the clearing bath.

brown tones are will

desired, the sulphide redeveloper

be unnecessary to use white

may

be used when

Avoirdupois

ounces ounces 3J4 ounces H ounce

Water

96

Sulphite, desiccated

6J

Hydroquinone *Boric .\cid, crystals

Potassium Bromide Sodium Hydroxide (caustic soda). Water to make Dissolve chemicals *

Use

crystalline boric

great difficulty and

its

acid

as

it

light.

First Developer for Direct Positive Prints

Sodium

If

2

150 .

.

.

in

grains

iH

ounces

1

gallon

[D-88]

Metric 750.0 cc 48.8 grams 24.4 ftrams 5.b (irams 2.6 grams

24.4 1 .0

grams liter

the order given.

specified

use should be avoided.

;

powdered boric acid dissolves with


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

302

It

volume

desirable to dissolve the caustic soda in a small

is

a separate container and then add

Then

stituents.

tainer

dilute the

employed

is

whole to the required volume.

should

dissolved, to prevent cracking the

is

by the heat evolved.

glass container full

a glass con-

If

in dissolving the caustic soda, the solution

be stirred constantly until the soda

Use

of water in

to the solution of the other con-

it

strength at 7o°F. (2i°C.).

Special Direct Positive Paper Developer

[SD-2]

Avoirdupois

Water (about

ounces ounce 7' 2 ounces 2)4 ounces

125° F.) (52° C.)

96

Elon

1

Sodium

Sulphite, desiccated ....;...

Hydroquinone Potassium Bromide

grains

150

Sodium Hydroxide (caustic soda). Cold water to make

.

.

.

31^2

ounces

1

gallon

Metric 750.0 cc 7.5 56.3 18.8 2.6 26.3

grams grams grams grams grams

1.0 liter

Dissolve chemicals in the order given.

Use

full

65^to 7o°F. (i8° to 2i°C.). recommended particularly as a first developer when desired on redevelopment. It is not suitable for making

strength at

This formula sepia tones are

is

enlargements.

Bleaching Solution

[R-9]

Avoirdupois

Bleaching Bath

Use

Water Potassium Bichromate

1

gallon

1)4

Sulphuric Acid (pure cone.)

1)^ fluid

ounces ounces

full

strength at 65° to 7o°F. (18° to 2i°C.).

Metric 1.0 liter 9.6 grams

12.0 cc

For more rapid

bleaching, however, the quantities of acid and bichromate

may

be

in-

creased. Clearing Bath Sodium Sulphite, desiccated.

Water

to

make

...

12 1

ounces

90.0

gallon

grams

1.0 liter

Redeveloper A. Black and white prints.

Use

first

developer (Formula D-88)

(i8° to 2i°C.).

full

strength at 65°to 70°F.

This operation must be conducted

in the light,

either strong artificial light or sunlight.

B. Sepia Tones. If sepia tones are desired,

white light

is

unnecessary and the

lowing redeveloper should be used after clearing:

fol-


FORMULARY

303

Sulphide Redeveloper

[T-19] Metric 20.0 f^rams

Avoirdupois

Sodium Sulphide Water

Use

to

inot sulphite)

300 i^rains 32 ounces

make

1.0 liter

strength at 65° to 7o°F. (18° to 2i°C.).

full

Fixing Bath Prints of slightly greater brilliancy

(Formula F-5)

regular fixing bath

D-88.

It

is

may

be secured by fixing in the

Formula

after redevelopment in

important to wash for at least 10 niinutcs to insure removal

of the fixing bath from the print.

It is

not necessary to use the fixing

bath after the sulphide redeveloper.

Rack and Tank Developer for Panchromatic Motion Picture Film

[D-89]

(Elon-Borax-Pinakryptol Green) It is

necessary sometimes to develop panchromatic motion picture

For such work

negatives without sampling.

it is

very convenient to be

able to inspect the negatives at intervals and observe the progress of de-

This

velopment. tion light

may

3.8 volt bulb

is

An

possible with the following developer.

inspec-

be prepared by fitting a two-cell hand ilashlight with a

and a

Series 3

filter.

Two

thicknesses of

white paper should be placed between the

filter

medium weight

glasses to reduce the

light intensity further.*

Metric

Avoirdupois

Elon

Sodium Sulphite, desiccated Borax, granular tPinakryptol Green (1 500 solution) :

Water

to

make

3 100 5

pounds pounds pounds

77 fluid ounces 120 gallons

3.0 )irams 100.0 ftrams 5.0 grams 5.0 cc 1 .0 liter

Dissolve chemicals in the order given. t

A

may

stock solution of the dye

be

made up by

dissolving

i

part of dye in

500 parts of water at i6o°F. (7i°C.).

Film should be developed

at least

i

minute

in

complete darkness be-

The properties of the developer are Formula D-76. The desensitizing action decreases

fore inspection with a safelight.

similar to those of

with age whether the solution

is

used or not.

If the

bath has stood for

some time, the desensitizing action should be determined and more dye added if necessary. Average time of development for panchromatic negative motion picture film

is

8 to 12 minutes at 65''F. (i8°C.).

variable density sound negatives * J. I.

"Improvements Crabtree.

J.

in

it is

6 to 8 minutes at

Laboratory Apparatus" by C. E. Ives, A. -iO (193')-

Soc. Mot. Picl. Hug. 17.

For

65°F. (i8°C.). J.

Miller,

and


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

304

Pyro Tray Developer

[D-90]

(For General Use)

Sodium Sulphite, desiccated. Sodium Bisulphite

make

to

ounces 145 grains

2

Stock Solution B Sodium Carbonate, desiccated

ounces

1.0 liter

23^ ounces 15 grains

Potassium Bromide Water to make

grams

73.0

1.0 gram 1.0 liter

ounces

32

grams grams grams

70.0 17.0 20.0

grains grains

245 290 32

Pyro

Water

Metric

Avoirdupois

A

Stock Solution

Dissolve chemicals in the order given.

For normal use take

i

part A,

i

part B, and

2

parts water.

Develop

4 to 6 minutes at 65°F. (i8°C.).

For greater contrast take For

less contrast

take

i

i

part A,

part A,

i

i

part B, and

i

part water.

part B, and 4 parts water.

Note : This developer has been used for many years at the Kodak Research Laboraand represents a satisfactory pyro developer. It was derived originally from the British Journal Almanac. Like all pyro developers, however, it is subject to rapid tories

deterioration because of oxidation.

P-aminophenol (Kodelon) Tropical Developer

[D-91]

Avoirdupois

Water (about 125° F.) (52° C.) Para-aminophenol Hydrochloride (Kodelon

24 ounces 100 grains

)

Sodium Sulphite, desiccated Sodium Carbonate, desiccated. Cold water to

ounce 2S0 grains ounce 290 grains 32 ounces 1

.

1

.

make Dissolve chemicals

Average time of development: 3 to 4 minutes at

in

7 to

7.0 50.0 50.0

grams grams grams

1.0 liter

the order given.

9 minutes at 65°F. (i8°C.)

and

8o°F. (26.7'^C.).

temperature of the solution

If the

Metric 750.0 cc

is

8o°F. (26.5°C.) or above, add

i^ ounces desiccated sodium sulphate to 32 ounces of solution (45 grams per liter).

Rinse, harden,

DK-15, page

[DK-93]

fix,

and wash

as

recommended

for

Formula

284.

P-aminophenol (Kodelon) -Hydroquinone-Kodalk Film and Plate Developer Avoirdupois

Water (about 125° F.) (52° C.) Para-aminophenol Hydrochloride (Koi.»elon)

Sodium

Sulphite, desiccated

Hydroquinone Kodalk Potassium Bromide Cold water to

make

16

ounces

Metric 500.0 cc

73 grains

5.0

ounce

30.0

1

36 grains 290 grains 7

grains

32 ounces

Dissolve chemicals in the order given.

2.5

20.0 0.5

grams grams grams grams

gram

1.0 liter


FORMULARY Develop at

roll film in

305

trays about 8 minutes or in tanks about lo minutes

65°F. (i8°C.).

Develop professional and cut

film in tanks

about

7

minutes and in

trays about 5^ minutes at 65°F. (i8°C.).

SPECIAL DEVELOPERS HAVING LIMITED USE Pyro Stain Developer (For Producinjl a Stain Imajie with a

Minimum

[SD-l]

of General Stain)

Metric

Avoirdupois

Sodium

Sulphite, desiccated

20 40 75 32

Pyro

Sodium Carbonate, desiccated Water

to

make

grains grains grains

1.4 (irams 2.8 grams 5.3 grams 1.0 liter

ounces

Dissolve chemicals in the order given.

Use without dilution. Develop about 6 minutes at 65 "^F. (i8°C.), and fix in a plain hypo bath. Reference: Chapter XI, page 244.

rinse,

Two-Bath Development Development

in

MI, page

Chapter

two successive baths

Two-Bath Developers Parker,

Jr.,

offers certain

129; also following papers:

advantages (see

"Some

Properties of

Motion Picture Film," J. I. Crabtree, H. /. Soc. Mot. Pict. Eng. 21, 21-53, (July Rapid Processing Methods," H. Parker, Jr., and J. I. Crabfor

and H. D. Russell,

1933) and " tree, Amer. Phot. 30, 67 et seq. (Feb. 1936).

Two- Bath Developer (For

Solution Elon

— First Bath

A

Sodium

Avoirdupois

Sulphite, desiccated.

..

.

Hydroquinone to

Solution B

make

— Second

Metric

grams grams grams grams grams

5

pounds pounds pounds pounds pounds

120

gallons

1.0 liter

10 100

pounds pounds pound

10.0 grams 100.0 grams 0.5 gram 0.01 gram

5 2

100 100

Sugar, granulated Sodium Bisulphite

Water

[SD-4]

Panchromatic Motion Picture Negative Film) 5.0 2.0 100.0

100.0 5.0

Bath

Sodium Carbonate, desiccated Sodium Sulphite, desiccated. .. Potassium Bromide .

Potassium Iodide Water to make Dissolve chemicals

.

.

Ji

70 120 in

each bath

Average time of development:

grains gallons in the

1.0 liter

order gi\en.

4 minutes in each bath at 65 °F.

(i8°C.).

The sugar and bisulphite in the first bath serve to restrain development and prevent the appearance of the image. The gelatin absorbs the solution and when the film is moved into the second bath, the alkali


.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

306

in this

bath acts on the absorbed developing agent and causes fairly

rapid development, which stops as soon as the absorbed developer

is

Reference should be made to the paper cited above for

used up. complete

details.

Two- Bath Developer

[SD-5]

(For Variable Density

Sound Records)

Solution A — First Bath

7 10 2

Sodium Sulphite, desiccated Sodium Bisulphite Sugar, granulated

Water

to

Metric

Avoirdupois

Elon

make

pounds pounds pounds pounds

7.0 10.0 2.0

100 120 gallons

100.0

pounds pounds

25.0 10.0

B — Second Bath Sodium Sulphite, desiccated Sodium Carbonate, desiccated ....

grams grams grams grams

1.0 liter

Solution

Water

to

120 gallons

Dissolve chemicals

Develop about

25 10

make

each bath

in

in the

3 minutes in the first bath

grams grams

1.0 liter

order nven.

and

2

to 3 minutes in the

second bath at 65°F. (i8°C.). Reference should be

made

to the

paper cited above for complete

details.

Rapid Two-Bath Developer

[SD-6]

(For Press Photography)

Bath (No. Water (about

First

125° F.) (52° C.)

24 44 365 88

Elon

Sodium

Sulphite, desiccated

...

Hydroquinone

Sodium Sulphate, desiccated Sodium Carbonate, desiccated Cold water to

.

grains grains grains

3.0 25.0 6.0 100.0 20.0

ounces

Sodium

1000 solution) (1 Sulphite, desiccated .... :

Potassium Bromide Water to make

drams

5

fluid

1

ounce 290 grains

20.0 cc 50.0 grams 2.0 grams 1.0 liter

grains

30 32

ounces

B

Formalin (37'; solution) Water to make

6'

2

32

ounces ounces in the

the No.

bath and treat for

i

i

Develop

i

1.0 liter

order given

the second bath, take equal parts of

Directions for Use:

200.0 cc

fluid

Dissolve chemicals in each bath

2 6.5°C.") in

1.0 liter

2)

Phenosafranine

To make

grams grams grams grams grams

A

Solution

Solution

750.0 cc

grains

290 32

.

ounces

ounces 145 grains

3

.

.

make

Second Bath (No.

Metric

Avoirdupois

1)

A

and B.

minute at 65° to 8o°F.

(18° to

bath, then transfer without rinsing to the

minute with thorough agitation.

No.

2

Rinse a few sec-

water or an acid rinse bath (Formula SB-i, page 307), and fix until clear in an acid hardening fixing bath (Formula F-5, page 310).

onds

in

For rapid

fixing, use

36% hypo

in the

F-5 formula or use the F-24


FORMULARY

307

hypo-bisulphite bath to which has been added

Wash

2^% ammonium

running water and dry rapidly with

briefly in

Reference should be

made

to the article cited

warm

above

chloride.

air.

for

complete

details.

RINSE (STOP) BATHS AND HARDENING BATHS Acetic Acid Rinse Bath for Papers Avoirdupois 32 ounces

Water Acetic Acid (28% pure) *

To make 28%

Ij

o

fluid

[SB-l]

Metric 1

ounces

.0 liter

48.0 cc

acetic acid from glacial acetic acid, dilute 3 parts of glacial acetic

acid with 8 parts of water.

Rinse prints for at least

seconds.

5

With a I to 2 seconds drain, the equivalent of approximately twentyfive 8 by lo-inch prints may be processed in i quart (i liter) of this bath before

it

becomes alkaline and should be discarded.

Acetic Acid Rinse Bath

[SB-la]

(For Use with Films, Plates, and Papers for Photo-Mechanical Processes)

Avoirdupois

Water Acetic Acid *

To make 28%

(28' c

pure)

acetic acid

Metric

32 ounces 4 fluid ounces

from

glacial

1.0 liter

128.0 cc

acetic acid, dilute

3

parts of glacial

acetic acid with 8 parts of water.

The

action of this bath checks development instantly, preventing

uneven spots and streaks when negatives are immersed

in the fixing

solution.

Hardener-Rinse Bath for Films and Plates

[SB-3]

(For Use at 65째 to 75째 F. (18째 to 24째 C.)

Metric

Avoirdupois

Water Potassium Chrome Alum

This bath

is

32 ounces 1

1

ounce

.0 liter

30.0

grams

intended for use in hot weather after development and

before fixation in conjunction with Formula F-5.

Agitate the negatives for several seconds

hardener and allow to remain

maximum

hardening.

in

when

first

immersed

in

the

the solution for 3 to 5 minutes to secure


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

308

Important: The bath should be renewed frequently and tendency for scum to form on the bing with cotton.

films,

it

if

there

is

any

should be removed by swab-

The bath should be skimmed each day

before use.

Tropical Hardener Rinse for Films and Plates

[SB-4]

(For Use at 75° to 95° F. (24° to 35° C.)

Water Potassium Chrome Alum *Sodium Sulphate, desiccated

Avoirdupois

Metric

32 ounces

1.0 liter

1

2

ounce ounces

30.0 60.0

grams grams

* If crystalline sulphate is preferred instead of the desiccated, use (140 grams) in the above formula.

After development in a concentrated developer such as

4^

ounces

DK-15, page

more than i second and then immerse minutes. Omit the water rinse above 85 °F.

284, rinse the film in water for not

SB-4 bath

in the

for 3

(29.4°C.) and transfer directly to the hardener bath for 3 minutes. tate for 30 to 45 seconds immediately after

immersing

Agi-

hardener

in the

or streakiness will result.

The hardening bath is a violet-blue color by incandescent light (clear when freshly mixed, but it ultimately turns to a yellow-green with

bulb) use;

then ceases to harden and should be replaced with a fresh bath.

it

An unused

bath

will

a partially used bath

keep indefinitely but the hardening properties of

fall off

rapidly on standing for a few days.

Non-swelling Acid Rinse Bath for Roll Film

[SB-5]

Water *Acetic Acid (28^; pure) tSodium Sulphate, desiccated

Water *

Avoirdupois

Metric

gallons

500.0 cc 32.0 cc 45.0 grams

5

to

40

acetic acid

from

ounces

3^ pounds

.

make

To make 28%

fluid

10

gallons

glacial

acetic

1.0 liter

acid,

dilute

3

parts of glacial

acetic acid with 8 parts of water. t

If

it is

desired to use sodium sulphate crystals instead of the desiccated sulphate,

use 14 ounces per gallon (105 grams per

Agitate the films

liter).

when immersed

in the

bath and allow to remain

about 3 minutes before transfer to the fixing bath. This bath (SB-5) is satisfactory for use to 8o°F. (26.5''C.). It should be replaced after processing about 100 rolls per gallon provided about

3 quarts of developer

by 100

rolls.

When

acid.

working at temperatures below 75° F. (24°C.), the

acid rinse bath in

have been carried into the acid rinse bath

The bath should not be revived with

may

life

of the

be extended by giving the films a few seconds' rinse

running water previous to immersion

in the acid rinse bath.


)

FORiMULARY

309

FIXING SOLUTIONS Acid Hardening Fixing Bath

[F-l]

(For All Grades of Papers)

Sodium Thiosulphate Water to make

When

(hypo).

Sodium

Metric

ounces ounces

240.0 liratns

32

dissolved completely, add Water (about

Avoirdupois 8

.

all

of the following hardener solution:

2M

125° F.) (52° C.)..

Sulphite, desiccated. pure) ;

ounces ounce fluid ounces ounce

J^

.

Acetic Acid (28< Potassium Alum

1.0 liter

1}4 J4

80.0 cc 15.0 grams 48.0 cc 15.0 ftrams

Dissolve chemicals in the order given, following the instructions given after the stock hardener (Formula F-ia). *

To make 28%

acetic acid

from

glacial

acetic acid,

dilute

3

parts of glacial

acid with 8 parts of water.

Cool the hardener solution after mixing and add it slowly to the cool hypo solution while stirring the hypo solution rapidly. The F-i fi.xing bath, prepared as instructed, will fix approximately sixty 8 by lo-inch prints per gallon (4 liters) or their equivalent in other sizes, if a water rinse is used or approximately one hundred twenty 8 by 1 0-inch prints per gallon (4 liters) if the acid rinse bath (Formula

SB-i)

is

used between development and fixation.

The temperature

of

the bath should be kept as near 70° F. (2i°C.) as possible.

Acid Hardener Stock Solution (For

Water (about

Preparing Formula

125° F.) (52°

Sodium

C).

Sulphite, desiccated *Acetic Acid (28' c pure)

.

.

...

Potassium Alum Cold water to make

*

To make 28%

acetic acid

Avoirdupois

Metric

56 ounces 8 ounces 24 fluid ounces 8 ounces

1700.0 cc 240.0 grams 750.0 cc 240.0 grams

1

Dissolve chemicals

from

[F-la]

F-1

in

gallon

4.0 liters

the order given.

glacial

acetic acid,

dilute

3

parts of glacial

acid with 8 parts of water.

To make up the hardener dissolve the chemicals in the order given. The sodium sulphite should be dissolved completely before adding the acetic acid.

After the sulphite-acid solution has been mixed thoroughly,

add the potassium alum with constant stirring. When dissolved make up to the final volume with cold water. A fixing bath is made quickly by adding i part of this hardener to


:

.

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

310

4 parts of I

25%

hypo

cool

solution, or 32 ounces (i liter) of hardener to

gallon (4 liters) of cool

hypo solution containing

2

pounds

of

hypo

to the gallon of water.

Acid Hardening Fixing Bath

[F-5]

(For Films

and

Plates)

Metric

Avoirdupois

Water (about

Sodium Sodium

125째 F.) (52째 C). Thiosulphate (hypo).

Sulphite, desiccated. *Acetic Acid (28^( pure) fBoric Acid, crystals

.

.

.

80

ounces

2

pounds

2

2

ounces ounces ounce ounces

1

gallon

.

...

2.5 liters

6 fluid 1

Potassium Alum Cold water to make

960.0 grams 60.0 grams 190.0 cc 30.0 grams 60.0 grams 4.0 liters

Dissolve chemicals in the order given. *

To make 28%

acetic acid

glacial acetic acid, dilute 3 parts of glacial acid

from

with 8 parts of water. t Crystalline boric acid

with great difficulty and

Films or plates should be fixed properly 5

Powdered boric

should be used as specified. use should be avoided.

acid dissolves

its

lo minutes (cleared in

in

The bath need not be discarded

minutes) in a freshly prepared bath.

becomes excessive, that is, and hardens well throughone hundred 8 by ten-inch films or

until the fixing time (twice the time to clear)

The

over 20 minutes.

out

its

useful

solution remains clear

About eighty

life.

to

plates (or their equivalent in other sizes)

The F-5

may

be fixed per gallon.

bath has the advantage over the older type of fixing baths, which do not contain boric acid, that it gives much better hardfixing

ening and has a lesser tendency to precipitate a sludge of aluminum sulphite throughout

its

useful

The hardener may

life.

also be

mixed separately as a stock solution as

follows

Stock Hardener Solution

[F-5a]

(For Preparing

Formula

F-5)

Avoirdupois

Water (about

125째 F.) (52째 C.)

Sodium

Sulphite, desiccated *Acetic Acid (28'~f pure) tBoric Acid, crystals

Potassium Alum Cold water to make

.

.

.

80 ounces

.

.

10

ounces

30 fluid ounces 5 10 1

Metric 2.5 liters

ounces ounces gallon

300.0 grams 940.0 cc 150.0 grams 300.0 grams 4.0 liters

Dissolve chemicals in the order given. *

To make 28%

acetic acid

from

glacial acetic acid, dilute 3 parts of glacial acid

with 8 parts of water. t Crystalline boric acid should be used as specified.

with great difficulty and

its

use should be avoided.

Powdered boric acid

dissolves


FORMULARY A

fixing bath similar to

F-5

made by adding

is

hardener solution to 4 parts of cool

hypo per gallon

A

line developers

especially satisfactory for use with highly alka-

is

such as

part of cool stock

i

hypo solution (2^ pounds the hypo rapidly.

t,o'^(

of water) while stirring

fixing bath that

311

D-19

or

D-ii

is

the following:

Acid Hardening Fixing Bath

[F-IO]

(For Use with Highly Alkaline Developers)

Metric

Avoirdupois

Water (about

125째 F.) (52째 C.)

ounces

64

Sodium Thiosulphate (hypo) Sodium Sulphite, desiccated

2^4

Kodalk

4

Acetic Acid

1

pure)

i28''t

Potassium Alum Water to make DissoKe chemicals

9 3

ounces fluid ounces ounces

1

ftallon

in

2.0 liters

pounds ounce

tlie

1320.0 30.0 120.0 285.0 90.0

ftrams ftrams ftrams cc

ftrams

4.0 liters

order given.

Fix for twice the time to clear the film of

its

milky appearance.

Wash

thoroughly and wipe each negative carefully before drying.

minimum

sludging

Fixing Bath for Films and Plates

[F-16]

This bath has good hardening characteristics and a

tendency throughout

Chrome Alum

its

useful

life.

A Sodium Thiosulphate (hypo). Sodium Sulphite, desiccated ..

Avoirdupois

Metric

2

pounds

2

ounces ounces

960.0 ftrams 60.0 (irams

Solution

Water

to

Solution

B

.

.

.

make

96

Water

32

Potassium Chrome Alum Sulphuric Acid (pure, cone.)

2 ...

I4

Pour Solution B slowly into Solution

Use water

3.0 liters

ounces ounces fluid ounce

A

1.0 liter

60.0 ftram 8.0 cc

while stirring

A

rapidly.

at a temperature not higher than i25째F. (52째C.)

dissolving the

chrome alum or the hardening properties

Rinse films thoroughly before

Important:

A

will

when

be impaired.

fixing.

fresh bath should be prepared frequently because this

formula rapidly loses

its

hardening properties with use, when it should With an old bath, there is a tendency for

be replaced by a fresh bath.

scum to form on the surface of the film. Any such scum should be moved by swabbing with cotton before drying.

Fixing Bath for Motion Picture Film

Chrome Alum Solution

Avoirdupois

A

Sodium Sodium Water

*

A

Thiosulphate (hypo)

2

Sulphite, desiccated

to

make

96

bath which fixes more rapidly

centration in the above formula to

1

2^/2

pounds ounce 290 grains ounces

re-

[F-23]

Metric 240.0 lirams 12.5 ftrams 750.0 cc

be obtained by increasing the hypo conpounds per gallon (300 grams per liter).

may


.

312

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS Solution B

Water

Sodium

20

Sulphite, desiccated.

Sulphuric Acid, 5"^^ solution. Potassium Chrome Alum .... Water to make


FORMULARY

313

Dissolve the hypo in one-half the total volume of water and then add the remaining chemicals in the order given after dissolving in a small

volume

of water (about i25°F. {52°C.).

Dilute with water to the re-

quired volume.

Revival

is

unnecessary with the above fixing bath as the hardening

properties are maintained and the bath will not sludge throughout useful

The

life.

solution

may

its

be used until exhausted with 400 feet per

when it should be replaced by a fresh bath. Formula F-25 may be prepared conveniently from a concentrated

gallon

stock hardener as follows:

Work

Stock Hardener for Motion Picture (For Preparing

Formula

Metric

Avoirdupois

Water (about

125° F.) (52° C.)

Sodium

Sulphite, desiccated Glacial Acetic Acid tBorlc Acid, crystals

25

500.0 cc 25.0 ftrams 50.0 grams

pounds

6 gallons 25 pounds 50 pounds 120 gallons

Potassium Alum Cold water to make

[F-25a]

F-25)

25.0 50.0

grams grams

1.0 liter

Dissolve chemicals in the order given. *

A

fixing bath prepared with the above solution will not sulphurize within a

period of 3 to 4 weeks at 70°F. (21 °C.). If the temperature 70°F. (21 °C.) the quantity of sulphite should be doubled. t

Use

crystalline

acid as

boric

specified

;

is

apt to rise above

powdered boric acid dissolves with

great difficulty.

For use add cool

hypo

i

part of cool stock hardener solution to 4 parts of a

30%

solution.

HYPO TEST FOR THOROUGHNESS OF WASHING Very small traces

of

hypo retained

the rate of fading of the image. quantities of prints

may

It is

hypo but the following

in films or prints greatly accelerate

extremely

difficult to test for

test will indicate

when

small

the film or

be considered reasonably free from hypo.

If prints give

a negative reaction by the following

antee that the prints

may

not ultimately fade.

test, it is

no guar-

For example,

if

the

hypo complexes would remain washing and would not be detected by this test.

prints were fixed insufficiently, insoluble in the prints after

Sodium Thiosulphate (Hypo) Test Solution (For Films, Plates,

and Papers)

Avoirdupois Distilled water

Potassium Permanganate Sodium Hydroxide (caustic

Water

(distilled) to

make

soda)..

Metric

6 ounces 4 grains 8 grains

180.0 cc 0.3 gram

8 ounces

250.0 cc

0.6

gram

[HT-la]


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

314

Films or Plates: Take 8 ounces (250 cc) of pure water

and add \ dram

film (No. 118 or 5

by

in a clear glass

HT-ia. Then take a 6 or 8 exposure equivalent (one 8 by lo-inch film; two

cc) of solution

i

(

No. 116) or

7-inch films, etc.) and allow the water to drip for 30 seconds into

the glass of test solution. violet color will turn

If a small

orange

percentage of hypo

present, the

is

about 30 seconds, and with larger concen-

in

trations the orange color will change to yellow.

In either case, the nega-

wash water and allowed to wash until a produces no change in color, which indicates that the hypo

tive should be returned to the

further test

content has been reduced to a safe margin, thereby insuring satisfactory

permanency under normal keeping conditions. Papers: Take 4 ounces (125 cc) of pure water in a clear glass and add (i cc) of solution HT-ia. Pour ^ ounce (15 cc) of this diluted dram ^ solution into a clean i-ounce graduate or similar container.

Then take

(4 by 5-inch or the equivalent) from the wash water and allow water from them to drip for 30 seconds into the ^ ounce of test

six prints

If a small

solution.

I

percentage of hypo

is

present, the violet color will

about 30 seconds and become colorless in about In either case the prints should be returned to the wash

change to orange minute.

in

water and allowed to wash, until a further color,

test results in

no change

which indicates that the hypo content has been reduced

in

to a safe

margin, thereby insuring satisfactory permanency under normal keeping conditions.

Note: Oxidizable organic matter if present in the water reacts with the permanganate solution and changes the color in the same manner as hypo. The water should therefore be tested as follows

When

:

made with

negatives or prints from the wash w'ater a similar should be made with the tap water. Add a volume of tap w-ater, equal to the wash water drained from the negatives or prints to a second test solution prepared as above from pure water. If the sample to which tap water has been added remains a violet color, this indicates the absence of organic matter and it will be unnecessary the

first test is

test

to repeat the test.

If the color

is

changed

slightly

by the tap water, the presence of

be shown by the relative color change of the two samples. For example, if the tap water sample turned pink and the wash water sample became yellow, it would indicate the presence of hypo, while if both samples remained the

hypo

in the prints will

same shade,

this

would indicate the absence of hypo.

Special Formalin Hardener

[SH-l]

(For Films

and

Plates)

Avoirdupois

Metric

Formalin (37% formaldehyde solution)

2}^

Sodium Carbonate, Water

to

make

desiccated

....

73 32

drams grains

ounces

10.0 cc 5.0 grams 1.0 liter


FORMULARY

315

This formula is recommended for the treatment of negatives which would normally be softened considerably by a chemical treatment in the removal of several types of stains, or by intensification or reduction. After treatment for 3 minutes in the hardening solution, films or plates

should always be rinsed and immersed for

5

minutes

a fresh acid fixing

in

bath and well washed before giving any further chemical treatment.

Special Supplementary Hardener (For

Solution

125째 F.) (52째

C).

.

Potassium Alum Water to make

Solution B Hot water (about 160째 F.) Borax, granular to

dissolved,

ounces 114 ounces fluid ounces 2 4J^ ounces ounces 64

45.0 grams 64.0 cc 135.0 grams

1

ounces ounce

500.0 cc 30.0 grams

64

ounces

32

.

Sodium Sulphite, desiccated .... Acetic Acid (28' o pure)

When

Metric

Avoirdupois

A

Water (about

[SH-2]

Bromide Papers)

(71째 C.)

16

1.0 liter

2.0 liters

add cold water

make

Cool Solution B and add

it

slowly to Solution

2.0 liters

A with constant

If these directions are followed, a clear solution will

the borax solution, while

still

warm,

is

added

stirring.

be obtained but

to Solution A,

if

an insoluble,

white precipitate will form.

This solution

is

recommended

overcome the tendency

for

bromide papers when necessary

to stick to the belts of

to

heated dryers.

Fix prints in the regular fixing bath, wash thoroughly, and place in the above hardener for 5 or lo minutes.

move

Then wash thoroughly and

re-

surplus water before drying.

Warning: This bath should not be used if prints are to be toned by the hypo-alum or redevelopment method because it has a detrimental effect

upon the

tone.

INTENSIFYING AND REDUCING NEGATIVES If

negatives need intensification or reduction,

it is

best to give

them

such treatment immediately after they have been washed. Much time is saved and the negatives, when dry, are ready for finishing. Precautions: Stains are sometimes produced during intensification or reduction unless the following precautions are observed: i. The negative

should be fixed and washed thoroughly before treatment and be free of scum or stain. 2. It should be hardened in the formalin hardener

(SH-i) before the

intensification or reduction treatment.

negative should be handled at a time and

oughly during the treatment.

it

3.

Only one

should be agitated thor-

Following the treatment, the negative

should be washed thoroughly and wiped

off carefully

before drying.


:

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

316

INTENSIFYING SOLUTIONS Mercury

[in-l]

The mercury is

If

Intensifier

recommended where extreme intensification desired but where permanence of the resulting image is not essential. permanence is essential either the chromium or silver intensifiers intensifier

is

should be used. After hardening in Formula

SH-i (page 314) and washing, bleach

the negative in the following solution until the image turns white; then

wash thoroughly

% %

Mercuric Chloride

The

Metric

Avoirdupois ounces 32

Water Potassium Bromide

1.0 liter

ounce ounce

22.5 22.5

negative can be redeveloped or blackened with

D-16;

or

or with lo^c

ammonia (28%

cone,

These solutions give progressively greater contrast

To

io% sodium

D-72 ammonia

phite solution; or with a developer such as Formula

grams grams sul-

(diluted 1:2)

diluted 1:9).

in the order listed.

increase contrast considerably, treat with the following solution:

Solution

Avoirdupois

A

Water

Sodium Solution

or Potassium Cyanide.

Metric

J^

ounces ounce

500.0 cc 15.0 grams

%

ounces ounce

500.0 cc 22.5 grams

16

B

Water

16

Silver Nitrate, crystals

* Cyanide is a deadly poison and should be handled with extreme care. Use rubber gloves and don't expose yourself to its fumes. Cyanide reacts with acid to form When discarding a solution containing cyanide, poisonous hydrogen cyanide gas. always flush it out of the sink quickly with water.

To

prepare the intensifier, add the silver nitrate Solution

potassium cyanide Solution

A

until a

permanent precipitate

is

B

to the

just pro-

allow the mixture to stand a short time and filter. This is called Monckhoven's intensifier. Redevelopment cannot be controlled as by the chromium method (Formula In-4) but it must go to completion.

duced

;

Note: See precautions on handling negatives, page 315.

[ln-4]

Chromium

Intensifier

Stock Solution Avoirdupois

Water to make Potassium Bichromate Hydrochloric Acid, cone

32 ounces 3 2

ounces fluid ounces

Metric 1.0 liter

90.0 grams 64.0 cc


FORMULARY For

use, take

the negative

317

the formalin hardener (SH-i, page 314).

thoroughly at 65° to yo^'F. (18° to 2i°C.) then wash redevelop in

Harden

part of stock solution to lo parts of water.

i

first in

5

Bleach

minutes and

daylight (not direct sunlight) in either

artificial light or

Nepera solution 1:4

or in the Elon-hydroquinone developer

D-72)

any rapid non-staining developer which does not sulphite. The time of redevelopment varies from

(Formula

diluted 1:3, or

contain an excess of

3 to 10 minutes at 65° to 70' F.

(

18"^ to

Then

2i°C.) depending on the degree

and immerse in a fixing bath (Formula F-i, page 309, or similar bath) for 5 minutes and wash thor-

of intensification desired.

rinse

oughly.

The

Greater intensification can be secured by repeating the process.

degree of intensification can also be controlled by varying the time of

redevelopment.

as

Warning: Developers containing a high concentration of sulphite such Formula D-76 are not suitable for redevelopment because the sul-

phite tends to dissolve the bleached image before the developing agents

have time Xotc

:

on

to act

it.

See precautions on liandling negatives, page 315.

Silver Intensifier

The

following formula

is

[ln-5]

the only intensifier

known

that will not

change the color of the image on positive film on projection. proportional intensification and of treatment. film.

The formula

is

easily controlled

is

by varying

equally suitable for positive and negative

Films should preferably be hardened in the formalin hardener

(Formula SH-i, page 314) before treating Stock Solution Stock Solution

Sodium Water

to

60.0 ftrams

make

ounces ounces

60.0

33^ ounces

lO.S.O

32

1.0 liter

2 .

.

make

2

32

Stock Solution 3 Sodium Thiosulphate (hypo)..

Water

Metric

ounces ounces

2

Sulphite, desiccated

to

in the intensifier solution.

Avoirdupois

1

Silver Nitrate Distilled water to

make

1

ounces

32

1

Sodium

Sulphite, desiccated

.

Water Store

in

350 96

make

Arams

.0 liter

grams

ounce

l.S.O

grains

24.0 grams 3.0 liters

ounces

a brown bottle.

Prepare the of Solution

to

3^

.

Elon

grams

.0 liter

Stock Solution 4

*

It gives

the time

intensifier solution for use as follows:

No.

2

to

i

obtain thorough mixing.

part of Solution No.

The white

i,

Slowly add

i

part

shaking or stirring to

precipitate which appears

is

then


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

318

dissolved

by the addition

of

part of Solution No. 3.

i

/\llow the re-

Then add, with

sulting solution to stand for a few minutes until clear.

No. 4. The intensifier is then ready for use and the negative should be treated immediately. The mixed intensifier stirring, 3 parts of Solution

is

stable for approximately 30 minutes at 70째F. (2i째C.).

The degree

of intensification obtained depends

ment which should not exceed 25 minutes. merse the film or plate

for 3

minutes

upon the time

of treat-

After intensification im-

in a plain

30% hypo

solution

and

then wash thoroughly. Note: See precautions on handling negatives, page 315.

Redevelopment

A

Intensifier

simple method of intensification for negatives consists of bleaching

and bromide bleach used for sepia toning (Formula T-ya, page 331) and blackening in the sodium sulphide bath exactly as in the ferricyanide

in print toning.

PHOTOGRAPHIC REDUCERS Photographic reducers

may

be classified into three types as follows:

A. Subtractive or cutting reducers which remove equal quantities of silver

from the high, intermediate, and low densities respectively.

have the

effect of clearing

up the highlights and therefore appear

crease the image contrast but they do not change

They to in-

They

gamma.

are

useful for treating fogged or overexposed images.

B. Proportional reducers which remove density in an is

They

proportional to the original density.

also visual contrast

and correct

for

C. Super-proportional reducers

which bear a greater proportion

therefore lower

gamma and

overdevelopment.

which remove density increments

to the original density as the

They

of the original density increases.

densities without destroying

amount which

shadow

magnitude

therefore reduce the highlight

detail

and are useful

for treating

overdeveloped negatives of contrasty subjects.

A.

SUBTRACTIVE REDUCERS Acid Permanganate Reducer

[R-2]

(For General Use)

Stock Solution

Avoirdupois

A

Water Potassium Permanganate.

32 ..

.

IJ^

Metric

ounces ounces

52.5

ounces fluid ounce

32.0 cc

1.0 liter

grams

Stock Solution B

Water Sulphuric Acid, pure cone

32 1

1.0 liter


FORMULARY

319

Harden the negative first in the special formalin hardener (Formula SH-i, page 314). The negative must be washed thoroughly to remove of hypo before it is reduced. For use, take i dram (4 cc) of drams (8 cc) of B, and 8 ounces (250 cc) of water. When the

all traces

A,

2

negative has been reduced sufficiently, place

(Formula F-i or similar type) stain.

it

bath

in a fresh acid fixing

few minutes to remove the yellow

Then wash thoroughly. add more water.

If reduction is too rapid,

as a stain remover as

it

Formula S-6, page 335 If

for a

one treatment

is

will attack the is

Do

recommended

R-2

not use Formula

image before removing the

stain.

for stain removal.

insufficient the process

may

be repeated, but

it is

necessary to wash thoroughly, otherwise the retained hypo will reduce the permanganate forming an objectionable stain. Note : If a scum forms on the top of the permanganate solution or a reddish curd appears in the solution, it is because the negative has not been sufficiently washed to remove all hypo, or because the permanganate solution has been contaminated by hypo. The separate solutions will keep and work perfectly for a considerable time The two solutions should if proper precautions against contamination are observed. not be combined until immediately before they are to be used.

They

will not

keep

long in combination.

A

close observance of the foregoing instructions

wise an iridescent

scum

after they are dry;

and

will

is

important.

Other-

sometimes appear on the reduced negatives

this is difficult,

if

not impossible, to remove.

Note: See precautions on handling negatives, page 315.

Farmer's Reducer (For

Solution

Avoirdupois

A

Water Potassium Ferricyanlde Solution

[R-4]

Amateur Use) 1

ounce

15 grains

Metric 32.0 cc 1.0

gram

B i2 ounces

Water

Sodium Thlosulphate (hypo)

1

ounce

10 30.0

liter

grams

Note: See precautions on handling negatives, page 315.

Add A

to

B and immediately pour

over the negative to be reduced,

been treated with the special formalin hardener solution (SH-i, page 314). The reducer solution decomposes rapidly after mixing the A and B solutions and therefore should be used at once. When

which has

first

wash thoroughly before dryLocal areas may be reduced with this reducer by applying the

the negative has been reduced sufficiently, ing.

solution with a cotton pad.

This formula

is less

active than

Formula R-4a given below.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

320

Farmer's Reducer

[R-4a]

(For Professional Use)

Stock Solution

Stock Solution B Sodium Thiosulphate (hypo).

Water

.

.

make

to

Metric

Avoirdupois

A

Water Potassium Ferricyanide

16 1}4

ounces ounces

500.0 cc 37.5 grams

16

ounces ounces

480.0

64

grams

2.0 liters

Harden the films or plates first with the special hardener (Formula SH-i, page 314). Then take stock Solution A, i ounce (32 cc), stock

make

Solution B, 4 ounces (128 cc), water to

A

to B, then

which preferably should be contained tive

32 ounces (i liter).

add the water and pour over the negative

When

in a white tray.

Add

to be reduced,

the nega-

has been reduced sufficiently, remove and wash thoroughly.

may

Farmer's reducer

also be used as a two-solution formula

ing the negative in the ferricyanide solution

by

treat-

and subsequently

Almost proportional reduction

the hypo solution.

method.

first

is

in

obtained by this

See Formula R-4b, page 322.

Note: See precautions on handling negatives, page 315.

Modified Belitzski Reducer

[R-8]

and Motion Picture Use)

(For Professional

This reducer well in a tank.

is

the only

known

single solution reducer

recommended

It is especially

which keeps

for treatment of dense,

contrasty negatives. Metric

Avoirdupois

Water (about

125° F.) (52° C.) Ferric Chloride, crystals

.

2'

Sodium

Sulphite, desiccated Citric Acid Sodium Thiosulphate (hypo) to

.

Sodium

6^ ounces

make

Treat the negative

in

1.0 liter

the order given.

used because

it

slows up the rate of reduction.

in the special formalin

page 314) and wash thoroughly.

mum

ounces

32

citrate should not be

ounces ounce grains

290

Dissolve chemicals *

2

1

.

750.0 cc 25.0 grams 75.0 grams 30.0 grams 20.0 grams 200.0 grams

grains

365

*Potassium Citrate

Water

ounces

24

.

hardener (Formula SH-i,

Use the reducer

full

strength for maxi-

reduction.

Immerse the negatives 70°F. (18° to 2i°C.). sired, dilute

I

for

i

to 10

minutes in the reducer at 65° to

Then wash thoroughly.

part of the solution with

i

If slower action is de-

part of water.

For motion picture work, the exhaustion

life

of the solution

150 feet per gallon. Note: See precautions on handling negatives, page 315.

is

about


FORMULARY

321

Iodine-Cyanide Reducer This reducer images because

is it

particularly suitable for extreme reduction of print

does not leave a residual stain. Metric

Avoirdupois

Sodium

or Potassium Cyanide.

.

Water

to

make

5.0 firams

73

tiralns 1}4 fluid ounces

Iodine stock solution

40.0 cc

ounces

32

1.0 liter

Cyanide is a deadly poison and sliould be handled with rul)I)er gloves in a room having good ventilation. The hands should always be washed carefully after use. *

Do not discard this solution into a sink containing acid, or the highly poisonous liydrogen cyanide gas will be formed. Flush it out of the sink (juickly with water.

Iodine Stock Solution Metric

Avoirdupois

Water Potassium Iodide

5

Iodine Crystals Dissolve chemicals

sufficient to

prepare

160.0 cc

i

8.0 8.0

grams grams

the order given.

in

This volume of iodine stock solution is

ounces

110 grains 110 grains

will

keep

for several

months and

gallon (4 liters) of the reducer solution.

After hardening the film with the formalin hardener (Formula SH-r,

page 314) immerse

in the iodine-cyanide solution.

The

reducer acts

similarly to other subtractive formulas but tends to attack the densest

The mixed

solution

and should be used as soon as minute at 65째F. (i8째C.).

possible.

portions slightly faster than the less dense areas. deteriorates rapidly after mixing

Average bleaching time, about Xolc

:

i

See precautions on handling negatives, page 315.

B.

PROPORTIONAL REDUCERS

Persulphate-Permanganate Reducer

[R-5]

(For Professional Use)

Avoirdupois

Stock Solution A

Water Potassium Permanganate Sulphuric Acid Stock Solution

(lO'/r

ounces

1.0 liter

4

grains

0.3 gram 16.0 cc

solution),

yi fluid

ounce

B

Water

Ammonium

Metric

32-

96

Persulphate

3

ounces ounces

3.0 liters

90.0

grams

Treat the negative first in the special formalin hardener (Formula SH-i, page 314) and wash thoroughly. Then take i part of Solution A to 3 parts of Solution B of Formula R-5. When sufficient reduction is secured, the negative should be cleared in a 1% solution of sodium bisulphite.

Wash

the negative thoroughly before drying.

does not keep well enough for motion picture work. Note: See precautions on handling negatives, page 315.

The

solution


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

322

Two

[R-4b]

Solution Farmer's Reducer

(For Professional

and Motion Picture Use)

This formula gives almost proportional reduction and corrects for overdevelopment.

The

which begins

solution,

Solution

solutions also keep to

much

better than the single

decompose almost immediately.

B Sodium Thlosulphate

Metric

Avoirdupois ounces 32

A

Water Potassium Ferrlcyanlde

14,

1.0 liter

ounce

7.5

grams

200.0

grams

Solution

(hypo)

..

6 Ji

.

Water

32

ounces ounces

1.0 liter

After hardening in the special formalin hardener (Formula SH-i,

page 314) and washing thoroughly, the negatives should be immersed in Solution A for i to 4 minutes with uniform agitation 65° to yo^F. (18° to 21° C). Then immerse in Solution B for 5 minutes and wash

The

thoroughly.

process

may

For the reduction of general

be repeated

if

dilute

i

fog,

more reduction

is

part Solution

A

desired.

with

i

part of water.

The

ferricyanide solution will keep indefinitely

daylight.

hypo

If

is

is

shielded from strong

The exhaustion

ferricyanide solution will be shortened.

ricyanide

if

introduced by alternate treatments, the life

life

of the

of the fer-

approximately 300 feet of motion picture film per gallon.

Note: See precautions on handling negatives, page 315.

Ferric

[R-7]

(For

When film

Alum Reducer

Motion Picture Work)

using the following reducer,

it

is

very important to keep the

under the solution surface during reduction as well as during sub-

sequent washing or stains will result. Metric

Avoirdupois

Water Sulphuric Acid, pure cone Ferric Ammonium Sulphate ric

ammonium

Water

When solution

ounces 1)4 fluid ounces

64

to

make

alum)

500.0 cc 10.0 cc

(fer-

2

ounces

1

gallon

15.0

grams

1.0 liter

mixing the solution, be careful to add the acid to the water

and not vice versa or the water

will boil

with explosive violence.

Films should be hardened with the alkaline hardener solution (For-

mula SH-i, page 314) and washed before treatment with the reducer solution. Use the reducer full strength at 65° to 70°F. (18° to 2i°C.).

Wash

thoroughly after treating with the reducer.


FORMULARY

323

The solution keeps indefinitely and has an average exhaustion life of 250 feet per gallon. Care should be taken to avoid contamination with hypo, which reacts with the solution and decreases its keeping life. Note: See precautions on handling negatives, page

315.

SUPER-PROPORTIONAL REDUCERS

C.

Persulphate Reducer

[R-l]

(For Overdeveloped Negatives of Contrasty Subjects)

Stock Solution

Water

Avoirdupois

Metric

ounces ounces

1.0 liter

32

Ammonium

Persulphate Sulphuric Acid, pure cone

2

%

grams

60.0

dram

3.0 cc

Treat the negative in the special formalin hardener (Formula SH-i, page 314) and wash thoroughly. Then take i part stock solution R-i and 2 parts water. When reduction is complete, immerse in an acid fixing bath (F-5, page 310) for a few minutes and wash thoroughly before drying.

If reduction is

too rapid, dilute the solution with a

further volume of water.

Note: See precautions on handling negatives, page 315.

TONING BATHS A. Toning Baths for Lantern Slides, Transparencies, and tion Picture Prints Three distinct methods of toning are possible: 1. Toning by direct development. 2. Toning by replacement of the silver image with inorganic

Mo-

salts

(metal tones). 3.

Toning with dyes (dye tones). I.

The by the

Toning by Direct Development

color of the silver

image produced by development

size of the silver particles

is

composing the image, and

to control the size of these particles

determined

it is

possible

and therefore the color of the image

by modifying the nature of the developer. The developer (Formula D-32) on page 287

will give pleasing

warm

black tones.

The range

of colors obtainable, however,

usually easier and color either

by

more

delicate

is

not very great and

it

is

certain to produce such slight modifications of

dye tinting or by giving a short immersion

of the diluted toning baths.

in

one


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

324

Toning by Replacement

2.

oÂŁ the Silver

Image with

Inorganic Salts Since most toning processes intensify the original silver image,

commence with

best to

the thin side.

a slide or positive print which

is

it

is

somewhat on

Experience will dictate the most suitable image quality

which yields the best

results with the various toning processes.

Stability of Solutions.

â&#x20AC;&#x201D;

All toning baths containing potassium

ferricyanide are sensitive to light, the ferricyanide being reduced to fer-

rocyanide, with the resulting formation of a sludge of the metallic ferro-

When

cyanide.

not in use, tanks should be covered to prevent exposure

and small volumes should be placed in dark brown bottles. also very important that no metallic surface, however small,

to daylight It is

should come in contact with the solutions.

Wooden

with hard rubber faucets should be used.

Motion picture

or stoneware tanks film should

be wound on wooden racks, free of metal pegs. details on toning motion picture film are given in the book and Toning Eastman Positive INIotion Picture Film." *

Complete " Tinting

Uranium Toner

[T-9] (For

Brown

to

Red Tones on

Slides or Films)

Metric

Avoirdupois

Small Scale

Larfte Scale

Uranium

2K pounds

(uranyl) Nitrate

Potassium Oxalate Potassium Ferricyanide

2]^ 1

Ammonium Alum

Hydrochloric Acid,

Water

6 10*^1

solution.

make

to

Dissohe

The

is

fluid

15

85

is

grains grains grains grains

IM drams

ounces

32

gallons

ounces

2.5 grams 2.5 grams 1.0 gram 6.0 grams 5.0 cc 1.0 liter

cliemicals in the order given.

and pale yellow

however, and should he stored

degree of toning

from brown It

77 120

pounds pound pounds

solution should be perfectly clear

light sensitive,

mum

.

35 35

produced

in

in color.

in the dark.

//

is

The maxi-

about lo minutes, the tone passing

to red during this time.

convenient to keep

io%

stock solutions of the constituent chemi-

compounding of a new bath. For motion picture work, 120 gallons of the above bath will tone about 12,000 feet of film without any appreciable change in the tone. A vol-

cals of the

ume

above toning bath

of acid

may

for quick

then be added equal to that originally used, when a may be toned. After toning the second quantity of

further 12,000 feet film, the

bath should be discarded.

After toning, wash for about 10

minutes, though the washing should not be prolonged, especially

water *

is

slightly alkaline since the toned

image

Motion Picture Sales Dept., Eastman Kodak

is

soluble in alkali.

Co., Rochester,

N. Y.

if

the


FORMULARY

325

Sulphide Toner (For Sepia

Potassium Ferricyanide Potassium Bromide Water to make

phite) to

13

grains

0.9 ftram

32

ounces

1.0 liter

1 .0

liter

(not sul-

three times the (|uaiUity of crystal sodium sulphide.

film

for 5 minutes,

(slide)

thoroughly bleached

is

and immersed

until thoroughly toned.

The

oughly

for 10 to 15

tone

much improved by

is

32

make

The well-washed washed

30.0 ftrams 15.0 grams

'2

B

Water

Use

Metric

ounce ounce ounces

1

Sodium Sulphide, fused *

Slides)

Avoirdupois

Solution A

Solution

[T-IO]

Tones on Lantern

in

Solution

B

for

in Solution

about

film (slide) should then be

the addition of a

say, 64 grains per 32 ounces or 4.5

minutes

2

washed thor-

The transparency

minutes before drying.

hypo

little

grams per

A,

of the

to Solution B,

liter.

Sulphide Toner

[T-lOa]

(For Sepia Tones on Motion Picture Film)

Solution

Avoirdupois

.\

Metric

20 pounds 5 pounds 120 gallons

Potassium Ferricyanide Potassium Bromide Water to make

B *Sodium Sulphide, fused

20.0

grams

5.0 grams 1.0 liter

Solution

(not

sulphite)

Water *

Use

to

1

make

ounces

1.7 grams 1.0 liter

positive should be bleached thoroughly after

4 minutes treatment so that the

the film. is

10 V2

three times the quantity of crystal sodium sulphide.

The well-washed

film

pound

120 gallons

in Solution

A

2

to

at 65째 to 7o째F. (18째 to 2i째C.),

image appears uniformly yellow on looking at the back of

Then wash

5

minutes and immerse

thoroughly toned.

A

in Solution

do no harm provided the solution

is

sulphide allowed to settle before use.

boiled

B

until the

sodium sulphide

trace of iron in the

and the precipitated

Wash

will

iron

10 to 15 minutes after

sulphiding and before drying.

[T-U]

Iron Toner (For Blue

Tones on Slides or Films) Metric

Avoirdupois Small Scale Large Scale

Ammonium

impound

Persulphate Iron and .\mmonium Sulphate (ferric

alumj

1

Oxalic Acid

3

Potassium Ferricyanide

1

Ammonium Alum

Hydrochloric Acid, 10%

Water

to

make

pound b}4 ounces pounds pound pounds

5 ISJ^ fluid ounces gallons 120

7

grains

0.5

gram

20

grains grains grains grains

1.4 3.0

grams grams gram grams

45 15

75

M dram 32

Dissolve chemicals in the order given.

ounces

1

.0

5.0 1.0 cc 1.0 liter


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

326

The method

of

compounding

this

bath

very important.

is

Each

of

the soHd chemicals should be dissolved separately in a small volume of

water, the solutions then mixed strictly in the order given, and the whole diluted to the required volume.

bath

will

be pale yellow

Immerse the

If these instructions are followed, the

and perfectly clear. from 2 to 10 minutes at 70°F. (2i°C.)

in color

slides or films

Wash

until the desired tone

is

obtained.

highlights are clear.

A

very slight permanent yellow coloration of the

minutes until the

for 10 to 15

clear gelatin will usually occur, but should be too slight to

on projection.

If the highlights are stained blue,

be detectable

then either the slide

was fogged during development, or the toning bath was

(film)

stale or

not mixed correctly. Since the toned image

soluble in alkali, washing should not be car-

is

ried out for too long a period, especially

if

the water

Life of the Bath for Motion Picture Work.

newed

after toning each 5,000 feet, the bath

feet per

120 gallons (480

is

is

slightly alkaline.

If the acid is re-

capable of toning 36,000

liters) of solution.

Mixed Iron and Uranium Tones.

— By mixing the uranium (T-9,

page 324) and iron (T-ii, page 325) toning solutions in different proportions, tones ranging from reddish-brown to chocolate are produced.

Analogous

results

may

be obtained by immersing

in

each solution suc-

cessively for varying times.

Dye Toning

3.

It is

not possible to obtain more than a limited

compounds owing

the use of colored inorganic of such

compounds

available.

number

by number

of tones

to the limited

Certain inorganic compounds, however,

such as silver ferrocyanide can be used as mordants for basic dyes such as Victoria green, safranine, etc.

If,

therefore, a silver

image

is

con-

verted more or less to a silver ferrocyanide image and then immersed in a solution of a basic dye, a

mordanted dye image

is

produced.

Immersion of a silver image in an acid solution of potassium ferricyanide will produce a satisfactory mordant image of silver ferrocyanide but,

if

the image

is

left too

mordanting action of the incorporating uranium

ferrocyanide

is

long in the acid ferricyanide bath, the

silver ferrocyanide

(uranyl)

nitrate

in

image

is

the bath,

destroyed.

By

brown uranyl

deposited along with the silver ferrocyanide which serves

as a signal to indicate

when

the film should be

removed from the mor-


FORMULARY When

danting bath.

brown,

image

if

will not

it

prolonged so that the

is

mordant as

well.

Uranium Mordanting Bath (Uranyl) Nitrate. Oxalic Acid Potassium Ferricyanide

Water

.

.

make

to

[T-17]

Avoirdupois

Stock Solution

Uranium

Directions for Mixing:

Metric

Large Scale

Small Scale

8 pounds 4 pounds 4 pounds 120 gallons

116 58 58 32

The uranyl

and should not contain an excess

to turn

has been formed to mordant basic

the time of immersion

appreciably colored,

is

commences

the black silver image just

sufficient silver ferrocyanide

dyes strongly but,

327

8.0 grams 4.0 grams 4.0 grams 1.0 liter

grains grains grains

ounces

nitrate should be of

of free nitric acid.

chemical separately in a small volume of water.

good quality

First dissolve each

Then add

the oxalic

acid solution to the uranyl nitrate solution and finally add the ferri-

cyanide solution.

If the

brown

ferricyanide, a

uranyl nitrate

readily in the oxalic acid.

and perfectly

clear.

is

added directly

to the

potassium

precipitate will be obtained which will not dissolve

The

After mixing, the bath should be light yellow solution should not be exposed to light

any

more than necessary. For use take

Time to

of

part stock solution and 4 parts water.

i

Mordanting: Immerse the

film (slide) at 65° to 70°F. (18°

2i°C.) until a very slight chocolate colored tone

move

at once.

If

ferior tones will

i^ to

The

2

mordanting

be produced.

minutes but the time

solution

may

is

prolonged

With

will

a

is

obtained and re-

much beyond

new bath

this point, in-

this will require

from

need to be increased as the bath ages.

be revived at intervals by adding a

little

of the con-

centrated stock solution.

Life of Bath.

— For motion picture work,

the bath should be dis-

carded after mordanting 10,000 feet of film per 50 gallons of solution.

Time

of

Washing after Mordanting.

— Wash

until the highlights

are free from yellow stain which usually takes about 10 to 15 minutes.

Do

not prolong the washing for more than 20 minutes or some of the

mordant

An

will

be washed out.

alternative mordanting bath

L. Chalkley, Jr.*

image *

"

is

The

practically colorless

Two

the following formula suggested

by

mordanted

and highly transparent.

Color Transparencies " by

raphy. 43, 23-31 (1929).

is

solution has the advantage that the

Lyman

Chalkley, Jr.

Amcr. Annttal of Photog-


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

328

Metric

Avoirdupois

Copper Sulphate Potassium Citrate, neutral ...

1 ounce 145 grains 8 ounces 165 grains

Glacial Acetic Acid

1

Ammonium

Thiocyanate .... potassium thiocyanate) Water to make (or

fluid

40.0 ftrams 250.0 grams 30.0 cc 25.0 grams

ounce

365 grains (424 grains)

(29.0

32 ounces

1

grams)

.0 liter

Dissolve the copper sulphate, potassium citrate, and acetic acid in

about 8oo cc (26 ounces) of water. in

Dissolve the thiocyanate separately

50 cc (i^ ounces) of water and add to the other solution.

Dilute to

volume.

months without deterioration and may be used With continued use a white flocculent premay appear, but this does no harm. When it begins to work too

This bath

will

keep

for

over again several times. cipitate

slowly,

it

should be discarded.

The Dye Bath

[T-17a]

Avoirdupois Small Scale Large Scale

tDye

1

JAcetic Acid, 10'^ Or Acetic Acid, glacial

Water

it

to

t

For methyl

t

To

make

â&#x20AC;&#x201D;

ounce

140 grains

ounces dye given

in the formula.

grains

â&#x20AC;&#x201D;

drams

1}4,

3}4 fluid ounces 50 gallons

32

violet use one-quarter the quantity of

convert glacial acetic acid into

10%

Metric 0.2 gram 5.0 cc (1.4 cc) 1.0 liter

3

acetic, take

i

part glacial acid and add

slowly to 9 parts water.

Thoroughly dissolve the dye in distilled hot water, dilute to volume with cold water.

and

The

following dyes are suitable for toning:

Safranine

A

filter,

add the acid


:

FORMULARY

329

image does not mordant sufficient wash thoroughly, immerse again in the

after dyeing lo minutes, the

If,

dye, remove the

fihii

(slide),

mordanting bath, wash, and re-dye.

Dye Tones.

Intermediate by mixing

â&#x20AC;&#x201D; Intermediate

the dye solutions or

either

For example,

successive baths.

if

colors

may

by immersing the

a reddish-orange tone

be obtained

film (slide) in is

desired, first

tone for a short time in the safranine bath and then in the chrysoidine bath, or the two baths

may

be mixed

in suitable

proportions and the tone

secured with a single treatment.

â&#x20AC;&#x201D;

It has been found that by omitting the ammonium Double Tones. alum from the iron toning formula, the half tones of the toned slide are white and the shadows blue. If this image is then immersed in any of the basic dye solutions as used for dye toning (Formula T-i7a) the dye is mordanted to the half tones while the shadows remain more or less ,

By

blue.

will.

Double Toning Bath

[T-18] Metric

Avoirdupois

Small Scale

Large Scale

Ammonium

Persulphate Iron and Ammoniuni Sulphate (ferric

J^

alum)

1

Oxalic Acid

3

Potassium Ferricyanide

1

to

The

pound pound 6 J^ ounces pounds pound

15J4 fluid ounces gallons 120

Hydrochloric Acid, lO'l

Water

make

(

Formula T- 1

1

,

grains

0.5

20 45 15

grains grains grains

1.4 grams 3.0 grams 1.0 gram 1.0 cc 1.0 liter

J^i

dram ounces

32

same

as for the iron

page 325).

Tone until the shadows are deep blue. minutes. Immerse in the basic dye solution used

Directions for Use: to 15

toning for tones

is

5 to 15

minutes until the desired depth of color

Wash

obtained.

5 to

The

of the iron toner

(Formula T-ii, page 325).

the double toning bath

Avoirdupois

Acetic Acid (glacial)

Water

to

make

The quantity

dye

in the half

is

the

same

Single Solution Dye Toner *Dye Acetone or Wood Alcohol Potassium Ferricyanide

Then for

10 minutes after dyeing until the high-

lights are clear.

life of

gram

7

instructions for preparing the bath are the

toning bath

wash ID

may

varying the dye solution used, the color of the half tones

be varied at

X

Hi

grains fluid

ounces

as that

[T-20] Metric x

grams

100.0 cc

gram

15 IJi

grains

1.

drams

32

ounces

5.0 cc 1.0 liter

of dye varies according to the dye used as follows


330

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS Tannin Heliotrope


:

FORMULARY B.

Toning Baths

331

for Papers

Hypo Alum Toning Bath (For

Amateur and

[T-la]

Professional Contact Paper)

Avoirdupois

Metric

90 ounces

2800.0 cc 480.0 drams

Cold water Sodium Thiosulphate (hypo)

16

ounces

Dissolve thoroughly, then add the following solution Hot water (about Potassium Alum

160° F. (71° C.))

.

20 4

.

ounces ounces

640.0 cc 120.0 (trams

the following solution (including precipitate), slowly to the

Then add

above hypo-alum solution while

stirring the latter rapidly.

Cold water

2

ounces

64.0 cc 4.2 ftrams 4.2 grams

60 grains 60 grains

Silver Nitrate, crystals Sodium Chloride (table salt)

After combining above solutions,

add water to make

1

gallon

4.0 liters

adding the sodium The and immediately afterwards the solution, including the milky white precipishould be added to the hypo-alum solution as directed.

Note

silver nitrate should be dissolved completely before

:

chloride, tate,

If boiling

changed, or

water if

is

used for mixing, or

the hypo-alum bath

bath

For

pour into a tray standing

use,

(49°C.).

and

way

proper manipulation technique

if

Never use

is

in

at a temperature

impairs the toning action of the used.

a water bath and heat to i20°F.

above i25°F. (52°C.), or

blisters

Prints will tone in 12 to 15 minutes depending

stains will result.

upon the grade

is

when adding the white black. The formation of

precipitate, the bath will turn a dirty gray or

a black precipitate in the bath in no

the order of mixing

if

not stirred

is

of paper.

The bath

will

be milky white

if

properly mi.xed.

Prints should be immersed thoroughly and separated occasionally, The especially during the first few minutes, to insure even toning. from developed and normal than black prints should be slightly denser

i^ to

2

minutes without forcing,

prints are toned, sponge off

one hour

in

running water.

to

any sediment

Soak dry

in

warm water and wash

prints in

Stock Bleaching Solution A Potassium Ferricyanide

*

Potassium Bromide Potassium Oxalate Acetic Acid (28', i Pure) Water To make 28% acetic acid from

8 parts of water.

for

water before toning.

[T-7a]

Sepia Redeveloper (For Chloride

After

produce good sepia tones.

and Bromide Papers) Avoirdupois 2J^ ounces 2 J^

ounces

6 J^ ounces \]4 fluid ounces

Metric "."^O 7.S.0 19.S.0

grams grams grams

40.0 cc 2.0 liters glacial acid with parts dilue acid, glacial acetic 3

64

ounces


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

332

Stock Redeveloping Solution B Sodium Sulphide (not sulphite)

Water To use, prepare

Bleaching Bath Stock Solution A

Water Redeveloper Stock Solution

B

Water

The

ounces ounces

45.0 grams 500.0 cc

16 16

ounces ounces

500.0 cc 500.0 cc

4 32

ounces ounces

125.0 cc

IJ^

will take

about

i

it

and the black

half tones are left

1.0 liter

washed thoroughly.

print to be redeveloped should be

bleaching bath and allow

in the

16

as follows:

Place

it

to remain until only faint traces of the

of the

This

shadows has disappeared.

minute.

Rinse thoroughly

in clean, cold water.

This

Place in redeveloping solution until original detail returns.

will

require about 30 seconds.

Give the print an immediate and thorough

water rinse; then immerse

for 5

minutes

in

a bath composed of F-ia

ounce (32 cc), water 16 ounces (500 cc). Remove the print from this bath and wash for one-half hour in running

hardener (page 309)

i

water.

The

color

and gradation

of the finished print will not be affected

by

the use of the hardener. Note : Do not use trays for bleaching that have any iron exposed. important as exposed iron may be a cause of blue spots.

(For Sepia

The advantage

may

Tones on Professional Contact and Enlarging Papers)

of this toning bath

is

brown

that a variety of excellent

be obtained by varying the time of toning.

The

prints

be removed from the bath at any time when a satisfactory color tained.

them

may

is

ob-

After fixing, wash the prints for a few minutes before placing

in the toning solution.

Metric

Avoirdupois Stock Solution A Warm water (about 130째 F.) (54째 C.) 1 gallon Sodium Thiosulphate (hypo) 2 pounds Ammonium Persulphate 4 ounces

Dissolve the hypo completely before adding the phate.

Stir the

phate.

If the

it

very

is

Nelson Gold Toning Bath

[T-21]

tones

This

bath vigorously while adding the

4.0 liters

960.0 120.0

grams grams

ammonium ammonium

persulpersul-

bath does not turn milky, increase the temperature until

does.

Prepare the following solution and add

it,

including precipitate, slowly

to the hypo-persulphate solution while stirring the latter rapidly.

bath must be cool when these solutions are combined.

The


FORMULARY Cold water

2

Silver Nitrate (crystals) Sodium Chloride (table salt)

Xotc

:

The

335

ounces

64.0 cc S.2 iJrams 5.2 (irams

75 tiralns 75 f^ralns

silver nitrate should be dissolved completely before

adding the sodium

chloride.

Stock Solution

B

Water

For

use,

8 ounces 15 grains

C^hloride

C,o\(i

add 4 ounces (125 cc)

of Solution

250.0 cc

'

1.0 ftrani

B

slowly to Solution

A

The bath should not be used until it and has formed a sediment. Then pour off the clear

while stirring the latter rapidly.

has become cold

Pour the clear solution into a tray standing

liquid for use.

in a

water

The temperature, when toning, should be between 100° and iio°F. (38° and 43°C.). Dry prints bath and heat to iio°F.

(43°C.).

should be soaked thoroughly in water before toning.

Keep

at

hand a black and white print

Prints should be separated at

desired tone

all

for

obtained, rinse the prints in cold water.

is

been toned, return them to the fixing bath I

hour

comparison during toning.

times to insure even toning.

When

After

for 5 minutes, then

all

the

have

wash

for

running water.

in

The bath should be revived at intervals by the addition of gold SoluThe quantity to be added will depend upon the number of prints toned and the time of toning. For example, when toning to a warm brown, add i dram (4 cc) of gold solution after each fifty 8 by 10tion B.

inch prints or their equivalent have been toned. solution

may

A

quantity of fresh

be added from time to time to keep the bath up to the

proper volume.

URANIUM, IRON, AND DYE TONES ON PRINTS Tones on paper may be obtained with uranium (Formula T-17) ranging from chocolate to brick red. as a

mordant bath

tinted unless

it

is

for

dye tones.

This formula

The paper

may

also be used

stock usually becomes

protected by squeegeeing temporarily to another

support coated with rubber cement.

Blue tones

may

be obtained with

an iron toning bath (Formula T-12).

Toned images obtained with these formulas are not absolutely permanent since they consist of a mixture of silver with one or more of the following compounds: silver ferrocyanide, dye, ferric, and uranyl ferrocyanides. On exposure to the atmosphere, which usually contains traces of hydrogen sulphide, the silver and uranyl ferrocyanides are converted to silver or uranyl sulphide which is usually apparent as a metallic


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

334

sheen on the surface of the toned print.

This sulphiding of the image

can be almost completely prevented by varnishing the prints with a nitrocellulose lacquer.

In

these processes, the final tone depends not only on the time of

all

toning but also on the density of the original print.

Iron Toning Bath for Blue Tones

[T-12]

Metric

Avoirdupois Ferric

Ammonium

Citrate

(green 58 58 58 32

scales)

Oxalic Acid, crystals Potassium Ferricyanide Water to make

Dissolve each chemical separately and

Immerse the well-washed print until the desired tone

is

4.0 4.0 4.0

ounces

1.0 liter

before mixing together.

filter

in the toning

obtained.

grams grams grams

grains grains grains

bath for lo to 15 minutes

Then wash

until the highlights are

clear.

Uranium Mordanting and Toning Bath

[T-17]

Stock Solution

Avoirdupois

Metric

116 grains 58 grains 58 grains 32 ounces

8.0 grams 4.0 grams 4.0 grams 1.0 liter

Uranium

Nitrate Oxalic Acid, crystals Potassium Ferricyanide

Water

to

make

Dissolve the uranium nitrate in a small volume of water Dissolve the oxalic acid separately and

i25°F.) (52°C.).

add the oxalic acid solution

to the

uranium

potassium ferricyanide separately;

uranium

and

nitrate

if

the solution

is

clear,

not clear,

If

then

Dissolve the

nitrate solution.

oxalic acid solution.

(about

filter;

add

it

filter

to the

before

mixing together.

For Use as lute

I

a

Toning Bath (Chocolate

part of the stock solution

toning time

is

2

to

The

print

may

For Use

as a

which usually requires from 10

Mordant for Dye Toning.

(T-17) with 4 parts

to

remove the yellow

i

part stock

minutes until the image turns a

2

Rinse for about stain

— Dilute

to

of water.

Treat the well-washed print about light chocolate color.

— Di-

As the brown and

be removed at any stage.

until the highlights are clean,

15 minutes.

solution

Brick Red).

parts of water.

increased, the tone changes from chocolate to

finally to brick red.

Wash

T-17 with

i

minute or

from the highlights.

15 minutes in the following dye bath:

less in

running water

Then immerse

for 10 to


FORMULARY Dye Bath

335

for Papers

[T-17B]

Avoirdupois

Dye

1000 solution) (1 Acetic Acid, 1% Solution

z fluid 6Ji fluid

:

Water

make

to

Volumes 1

Red

2

Yellow

3

Orange

Tone No.

4

Blue

Tone No.

5

Brilliant

Dye Solution

Safranlne A .\uramlne

ounces

3,'4

cc

x

drams

25.0 cc

ounces

32

of 1: 1000

Tone No. Tone No. Tone No.

Metric

1.0 liter

for Various Colors fluid

314 fluid

ounces ounces

100.0 cc 100.0 cc

Use equal parts of Nos. 1 and 2; then add i'i fluid ounces (100 cc) of the mixed dye solution when preparing the acid dye bath. 100.0 cc 3]^ fluid ounces

Victoria Green

Green

3 '4

Use equal parts of Nos. 2 and 4; then add 3,'i fluid ounces (100 cc) of the mixed dye solution when preparing the acid dye bath. fluid ounces 100.0 cc

5'

fluid

Green

Tone No. Tone No.

6

Blue

7

Violet

Methylene Blue BB Methyl Violet

Mixtures of the

follovk^ing

may

2

drams

20.0 cc

also be used:

Victoria Green plus

Methyl Violet

Victoria Green plus Methylene Blue

Methyl Violet plus Auramine Methyl Violet plus Victoria Green The dye toned print should be washed in running water traneous color is removed from the highlights.

until all ex-

STAIN REMOVERS AND TRAY CLEANERS may

Developer or oxidation stain film for 2 or 3

minutes

be removed by

in the alkaline formalin

page 314), then washing

for 5

first

hardening the

bath (Formula SH-i,

minutes and bleaching

in the following:

Stain Remover for Films and Plates Stock Solution

A

Water Potassium Permanganate. Stock Solution B

..

.

Gold water Sodium Ghlorlde (table salt). Sulphuric Acid, pure cone. .

Water *

Add

to

make

32 75

ounces

1.0 liter

grains

5.2

16 2}4

ounces ounces fluid ounce ounces

H

.

32

the sulphuric acid slowly with stirring or the solution

[S-6]

Metric

Avoirdupois

grams

500.0 cc 75.0 grams 16.0 cc 1.0 liter

may

boil with explosive

violence and burn the hands or face.

For use take equal parts of Solutions

The

A

and B.

solutions should not be added together until ready for immedi-

ate use, since they do not keep long after mixing.

All particles of per-

manganate should be dissolved completely when preparing Solution A, since undissolved particles are likely to produce spots on the negative.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

336

Bleaching should be complete

The brown

minutes at 65째F. (i8째C.).

in 3 to 4

manganese dioxide formed best removed by immersing the negative in a i stain of

in the

%

bleaching bath

sodium bisulphite

is

solu-

Rinse well, expose to sunlight or arclight then develop with any

tion.

non-staining developer such as Formula D-51, page 289, or Formula

D-72

diluted

I

part to

water

parts

2

(page

Then wash

292).

thoroughly.

Warn'mg: Developers containing a high concentration of sulphite, such D-76, are not suitable for redevelopment because the sulphite tends to dissolve the bleached image before the developing agents act upon it.

as

Hand

[S-5]

Stain Remover

Water Potassium Permanganate Solution B Water

]4

amount

the hands with a small

rinse with Solution

A

16

more vigorous

as developer stains

B which stain is

will

1.0 liter

ounce ounces ounces

32

Sodium Bisulphite

Rub

Metric

Avoirdupois ounces 32

Solution A

grams

7.5

1.0 liter

480.0

grams

of Solution A, rinse in water; then

remove the

stains.

remover which acts on most ink stains as well

given in Chapter XII, page 266.

Tray Cleaner

[TC-1]

(For General Use)

Metric

Avoirdupois

Water Potassium Bichromate

32 ounces 3 ounces 3 fluid ounces

Sulphuric Acid, pure cone

Pour a small volume

of the tray cleaner solution in the vessel to be

cleaned.

Rinse the solution around

all parts,

then pour

it

times with water until solution will

some

remove

silver stains

in the vessel so that

it

has access to

out and wash the tray thoroughly six or eight all

traces of the cleaning fluid disappear.

stains caused

and dye

stains,

by oxidation products

and

is

This

of developers,

a very useful cleaning agent.

Tray Cleaner

[TC-2] (For

Solution

Removal

A

Water Potassium Permanganate Sulphuric Acid, pure cone

Add

1.0 liter

90.0 grams 96.0 cc

of Silver Stains)

Avoirdupois 32 73 2.V2

ounces grains

drams

Metric 1.0 liter 5.0 grams

10.0 cc

the sulphuric acid slowly while stirring the permanganate solu-

tion rapidly.


FORMULARY

337

B

Solution

Water

32 145

Sodium Bisulphite

For use pour Solution

A

ounces

1

.0 liter

10.0

(irains

Arams

and allow it to remain for a few Apply Solution B and wash thoroughly. remove most types of stains, but it is especially recinto the tray

minutes, then rinse with water.

This formula

ommended

will

removal of

for the

silver stains.

CLEANING DEEP TANKS Use hypochlorite solution or paste ter

as directed on page 265 of

Chap-

XII.

Reference should also be

made

to

Chapter XII, page 262,

on removal of special types of

tional information

for addi-

stains.

Kodalk Fine Grain Developer (For Use

Water (about

Avoirdupois 96 ounces

125° F.) (52° C.)

Elon

Sodium

grains 290 13J4 ounces grains 116

Sulphite, desiccated ....

Kodalk Potassium Sulphocyanate (Thiocyanate)

58 29

Potassium Bromide Cold water to make

1

Dissohe chemicals

Time

Plates)

Metric 750.0 cc

2.0

grams grams grams

1 .0

gram

5.0

100.0

grains grains gallon

0.5 gram 1.0 liter

in the order given.

of development, 15 to 25 minutes in a tank at 65°F. (18° C.)

Decrease the time about 2o^r for tray

according to the contrast desired. use.

[DK-20]

With Roll Films, Film Packs, Cut Films, and

Develop

underexposures fully for best results.

Replenisher Solution (For Use

[DK-20R]

With Formula DK-20) Metric

Avoirdupois

Water fabout

ounces ounce liH ounces

125° F.) (52° C.)

96

Elon

Sodium

1

Sulphite, desiccated

Kodalk Potassium Sulphocyanate (Thiocyanate)

2

Potassium Bromide Cold water to make

290

grains

ounces, 290

grains grains gallon

58 1

750.0 cc 7.5 100.0 20.0

grams grams grams

5.0 grams 1.0 gram 1.0 liter

Dissolve chemicals in the order given.

Add to the tank as Deep Tank Use.

necessary to maintain constant volume.

A

throughout the developer

given highlight density will be maintained life for

stant temperature provided the

a constant development time at a con-

volume of

repleni.sher

added

is

6 gallons per looo rolls of film (80,000 square inches) processed.

about


PART B. TABLE OF SOLUBILITIES OF PHOTOGRAPHIC CHEMICALS The

following table

ter to

given to serve as a guide

is

solutions of chemicals.

Since a solution

is

a temperature approximating 40° F.,

a stock solution stronger than

is

indicated

when preparing

stock

apt to become cooled in winit is

not advisable to prepare

by the

solubility of the chemi-

cal at this temperature.

Chemicals as supplied commercially under the designation

were used

"

for the determination of the solubility values.

Grams Substance

— Formula

in 100 cc of

Saturated Solution at 40° F. (4.4° C.)

70° F. (21.1° C.)

Acid, Acetic

(CH3COOH)

Mixes in

all

proportions

Acid, Citric

(CH2COOH)2.C(OH)COOH

75

85

Acid, Hydrochloric

HCl

Mixes in

all

proportions

Acid, Oxalic

(COOH)2.2H20

7

14

Acid, Sulphuric

Mixes in

HoSO^

all

proportions

Acid, Tartaric (dextro)

(CHOHCOOH)2.H20 Alum,

70

75

Ammonium

(NH4)2Al2(S04)4.24H20

Alum, Iron

6

15

46

57

6

11

15

20

(Ferric)

(NHj )2Fe2 (804)4. 24 H2O

Alum, Potassium K2AI2 (804)4. 24 HjO Alum, Potassium Chrome K2Cr2 (804)4. 24 H2O Amidol (See Diaminophenol Hydrochloride)

Ammonia NH4OH

Mixes in

Ammonium Bromide NHjBr

50

Ammonium

Carbonate (NH4)2C03.H20

Ammonium

Chloride

NHiCl

Ammonium

Iodide

NH4I

Ammonium

Oxalate (NH4)2C204.H20 Ammonium Persulphate (NH4)28208

Ammonium Thiocyanate or Ammonium Sulphocyanide NH4CNS

Ammonium

Thiosulphate, anhydrous

(NH4)28203

Athenon (para-oxyphenyl glycin) C6H4(OH)(NH.CH2COOH) Borax (Sodium Borate) Na2B4O7.10H,O Boric Acid

H3BO3

all

proportions

C.P."


TABLE OF SOLUBILITIES Grams Substance

— Formula

(See

40° F. (4.4° C.)

Potassium Hydroxide)

Caustic Soda

Sodium Hydroxide)

Copper Sulphate, crystal CuS04.5H,0 Dlaminophenol Hydrochloride (Amidol)

C6H3(OH)(NHO-HCI1, 2, 4) Elon (monomethyl para-aminophenol sulphate) CeH^fOHiiNHCHs .hH:S04(l. 4) Ferric Alum (See Alum, Iron) (Ferric) Ferric Ammonium Citrate

Ferric Chloride

FeCl3.6H;0 Ferrous Sulphate

FeS0,.7H;0 Formalin {ST^c Formaldehyde)

CHoO Glycln

Athenon) Gold Chloride AUCI3.2H0O Hydroquinone (See

CeH4(OH);(l, 4)

Hypo

(See

Iron and (See

Sodium Thlosulphate

Ammonium Alum, Iron)

Sulphate (Ferric)

Kodalk Kodelon (See Para-aminophenol Oxalate) Lead Acetate Pb(CH3C02)o.3H,0 Lead Nitrate

Pb(N03).

Mercuric Chloride HgCl, Para-aminophenol Oxalate (Kodelon) CfHi (OH)(NH,).H(COOH)2(l, 4) Para-oxyphenyl Glycin (See Athenon) Potassium Bichromate

Potassium Bromide

KBr Potassium Carbonate, anhydrous K,C03 Potassium Chloride KCl Potassium Citrate

CHjCOOK ),C. (OH)COOK. H2O Potassium Cyanide

KCN

Potassium Ferrlcyanlde K3Fe(CN),;

Potassium Ferrocyanlde K4Fe(CN)6-3HjO Potassium Hydroxide (Caustic Potash)

KOH

Potassium Iodide KI Potassium Metabisulphlte K.S^Os

Potassium Oxalate

(COOK),.H,0

In 100 cc of

Saturated Solution at

Caustic Potash

(See

339

25

70° F. (21.1° C.)'


340

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS Grams Substance

40° F. (4.4° C.)

Potassium Permanganate

KMnOi

3.25

Pyroftallol (Pyro)

C„H,(OH)3(l, Rochelle Salts (See

2, 3)

Sodium, Potassium Tartrate)

Silver Nitrate

AgNOi Sodium Acetate, anJiydrous

CHjCOONa

Sodium Acetate, crystal CHsCOONa.SH.O Sodium Bicarbonate

(triliydrate)

NaHCO,

Sodium Bisulphite NaHSOi{Na2S,05)

Sodium Borate (See Borax) Sodium Bromide NaBr Sodium Carbonate, anhydrous Na.CO,

Sodium Carbonate, monohydrated

NaXOj

HO

Sodium Carbonate,

crystal

NaoCOi.lOH.O

Sodium Chloride NaCl

Sodium Cyanide

NaCN

Sodium Hydroxide

(caustic soda)

NaOH

Sodium Phosphate, Na,HP0j.l2H,0 Sodium Phosphate,

dibasic, crystal tribasic crystal

NajPOj.liHoO Sodium, Potassium Tartrate (Rochelle NaKC4H^06.4H,0 Sodium Sulphate, anhydrous Na.SOi

Sodium Sulphate,

crystal

Na,SO4.10HoO

Sodium Sulphide, fused NaS Sodium Sulphide, crystal Na,S.9HoO Sulphite, anhydrous Na.SO, Sodium Thiosulphate, crystals (Hypo) Na.S.Oa-SH.O Thiourea

Sodium

N,H,CS Uranyl Nitrate UOo(NOi)2.6H,0 Wood Alcohol

CH,OH

in 100 cc of

Saturated Solution at

— Formula

Salts)

70° F. (21.1° C.)


PART

C. LIST OF MANUFACTURERS OF APPARATUS AND SUPPLIES*

Acid Resisting Paints, See Paints Agitators and Stirrers

New York, N. Y. Mixing Equipment Co., Inc., Rochester, N. Y. New England Tank & Tower Co., Everett, Mass. Alsop Engineering Corp.,

Air Conditioning Apparatus Carrier Engineering Corp., Newark,

N.

J.

Surface Combustion Corp., Toledo, Ohio.

Westinghouse Electric

& Mfg.

Co., E. Pittsburgh, Pa.

York Ice ^Machinery Corp., York, Pa. Alberene Stone Alberene Stone Co., New York, N. Y. Asphalt, See Flooring and Oxygenated Asphalt Johns Manville Sales Corp., New York, N. Y. Balances, See Weighing Equipment Barrels and Drums, Mixing Groca ]\Ianufacturing Co., Chicago,

Lee Metal Products Co., Lalanti

&

Grosjean

IVIfg.

Brick, Acid Resisting,

for

111.

Inc., Pittsburgh, Pa.

Co.,

Woodhaven, N. Y.

Tank Linings

â&#x20AC;&#x201D; See Stoneware

Cement, Waterproof B. F. Goodrich Co., Akron, Ohio (Plastikon)

Cooling Equipment, See Refrigeration Equipment Drums, Mixing, See Barrels

Dyes Bachmeier

&

Co., Inc.,

New

York, N. Y.

DuPont de Nemours Co., Wilmington, Eastman Kodak Co., Rochester, N. Y. E.

I.

Del.

New York, N. Y. New York, N. Y. & Chemical Co., New York,

General Dyestuffs Corp., Grasselli

Chemical Co.,

National Aniline

N. Y.

Enameled Ware Pfaudler Co., Rochester, N. Y.

Fans, See Ventilation * This list of apparatus

and supplies are known

manufacturers represents those firms whose equipment work. Manufacturers not

to be satisfactory for photographic

included are invited to submit details of their products to the authors for possible inclusion in future editions.


342

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

Faucets Crane Co., Chicago,

111.

Standard Sanitary Mfg. Co., Pittsburgh, Pa. Filters

Alsop Engineering Corp.,

Commercial Filtrine

New

York, N. Y.

Filters Corp., Boston,

Mass.

Manufacturing Co., Brooklyn, N. Y.

Jones Manufacturing Co., Boston, Mass. (Small Water Filters)

Karl Kieffer Co., Cincinnati, Ohio.

Wm.

& Sons Co., Oakmont, Pa. D. F. Sperry & Co., Batavia, 111. Flooring, Asphalt Mastic, Concrete, Etc. B. Scaife

Construction supply houses in

all cities.

Flow Meters and Controllers American Instrument Co., Washington, D. C.

Brown Instrument Crane

Co., Philadelphia, Pa.

Co., Chicago,

111.

Davis Regulator Co., Chicago,

111.

Fischer and Porter, Philadelphia, Pa.

Foxboro Instrument Co., Foxboro, Mass. Mason-Neilon Regulator Co., Boston, Mass. Schutte and Koerting, Philadelphia, Pa. Taylor Instrument Co., Rochester, N. Y. Gages, Temperature See Thermometers

Glassware Corning Glass Works, Corning, N. Y.

Kimble Glass

Co., Vineland,

N.

J.

Will Corporation, Rochester, N. Y,

Heat Exchangers (Water Heaters Operated by Steam) Elliott Co., Pittsburgh, Pa.

Whitlock Coil Pipe Co., Hartford, Conn.

Hose, Rubber

— See Rubber Equipment

Humidity Control, Hygrometers Newark, N. J. Foxboro Instrument Co., Foxboro, Mass. Carrier Engineering Corp.,

Taylor Instrument Co., Rochester, N. Y. Jars, Stoneware

— See Stoneware

Laboratory Supplies Central Scientific Co., Chicago,

111.

Fisher Scientific Co., Pittsburgh, Pa.


LIST OF A. H.

Thomas

MANUFACTURERS

343

Co., Philadelphia, Pa.

Will Corporation, Rochester, N. Y.

Lacquer, Nitrocellulose Eastman Kodak Co., Rochester, N. Y. (No. 51 19) Mats, Rubber See Rubber Equipment Nickel, Monel, Inconel International Nickel Co., New York, N. Y. Oxygenated Asphalt Standard Oil Company (Any city in the U. S.)

â&#x20AC;&#x201D;

Pails, Corrosion Resisting

N. Y. (Stainless Steel) B. F. Goodrich Rubber Co., Akron, Ohio (Rubber Lined Iron) Lalanti & Grosjean Mfg. Co., Woodhaven, N. Y.

Anti-corrosive ]\Ietal Products Co., Albany,

Paints, Corrosion Resisting

Eastman Kodak Co., Rochester, N. Y. (Kodacoat) Wolf & Dolan, San Francisco, Calif. (Probus) Paints, Rubber Colvulc Rubber Co., Norfolk Downs, Mass. B. F. Goodrich Rubber Co., Akron, Ohio. Piping American Hard Rubber Co., New York, N. Y. A. M. Byers Co., Pittsburgh, Pa. (Wrought Iron) Crane Co., Chicago, 111. (Black and Galvanized Mild Steel) B. F. Goodrich Rubber Co., Akron, Ohio (Rubber Lined Iron) Joseph Stokes Rubber Co., Trenton, N. Plastics, Synthetic,

J.

Laminated Bakelite Corp.,

New

York, N. Y.

Porcelain Equipment Coors Porcelain Co., Golden, Colo.

Pumps,

Corrosion Resisting

Allis-Chalmers Mfg. Co., Milwaukee, Wis.

American Hard Rubber Co., New York, N. Y. A. S. Cameron Steam Pump Works, New York, N. Y. Goulds Pumps, Inc., Seneca Falls, N. Y. Northern Pump Co., Minneapolis, Minn.

Rumsey Pump

Co., Seneca Falls,

N. Y.

Taber Pump Co., Buffalo, N. Y. Worthington Pump & Machinery Corp., New York, N. Y. Refrigeration Equipment Copeland Products, Inc., Mt. Clemens, Mich.


PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

344

General Motors Corp., Detroit, Mich. General Electric Co., Schenectady, N. Y.

&

Kellogg Compressor

Manufacturing Corp., Rochester, N. Y.

Halsey W. Taylor Co., Warren, Ohio. Kelvinator Corp., Detroit, Mich.

Westinghouse Electric

&

Manufacturing Co., Pittsburgh, Pa.

Rubber, Equipment and Linings American Hard Rubber Co., New York, N. Y. B. F. Goodrich Rubber Co., Akron, Ohio. Goodyear Tire and Rubber Co., Akron, Ohio. U. S. Rubber Co., New York, N. Y. Scales, See Weighing Equipment Sinks, Laboratory Alberene Stone Co.,

New

York, N. Y.

M.

A. Knight, Akron, Ohio.

U.

S.

New

Stoneware,

York, N. Y.

Skid Platforms, Stackers, Trucks Lewis-Shepard Co., Boston, Mass.

Nutting Truck Co., Chicago,

Softeners, Water

— See ^

111.

Water Softeners

Stainless Steel Allegheny Steel Co., Brackenridge, Pa. Carpenter Steel Co., Reading, Pa. Crucible Steel Co., Syracuse, N. Y. Ingersoll Steel

Ludlum

&

Disc Co., Chicago,

111.

N. Y. Co., Youngstown, Ohio.

Steel Co., Watervliet,

Republic Steel

Midvale Co., Pittsburgh, Pa. U. Stills,

S. Steel

Corp., Pittsburgh, Pa.

Water

Barnstead

Still

&

Sterilizer Co., Inc., Boston,

Precision Scientific Co., Chicago,

Mass.

111.

F. J. Stokes Co., Philadelphia, Pa.

Stirrers, See Agitators

Stoneware, Corrosion Resisting General Ceramics Co.,

New

— Acid Resisting Brick York, N. Y.

Maurice A. Knight, Akron, Ohio. U. S. Stoneware Co., New York, N. Y. General Refractories Co., Philadelphia, Pa.

Alberene Stone Co.,

New

York, N. Y.


LIST OF INIANUFACTURERS

Tanks Metal

345

Downingtown Iron Works, Downingtown, Pa. Groen INIanufacturing Co., Chicago,

111.

(Stainless

Steel)

&

Lalanti

Grosjean Corp., Woodhaven, N. Y.

Lancaster Iron Works, Inc., Lancaster, Pa.

Rubber-lined

Struthers Wells Co., Warren, Pa. American Hard Rubber Co., New York, N. Y.

B. F. Goodrich Rubber Co., Akron, Ohio.

— Wood —

Stone

See Stoneware

Acme Tank Co., New York, N. Y. Atlantic Tank Co., North Bergen, N. J. Baltimore Cooperage Tank & Tower Co., more, Md. W. E. Caldwell Co., Louisville, Ky. Eagle Tank Co., Chicago, 111. Johnson-Carlson, Chicago,

Balti-

111.

Kalamazoo Tank & Silo Co., Kalamazoo, Mich. New England Tank & Tower Co., Everett, Mass.

Thermometers and Temperature Regulators Bristol Co., W^aterbury,

Brown Instrument

Conn.

Co., Philadelphia, Pa.

Foxboro Instrument Co., Foxboro, Mass. Taylor Instrument Co., Rochester, N. Y.

Trays Eastman Kodak

Co., Rochester,

N. Y.

& Grosjean Corp., Woodhaven, N. Y. Trucks for Moving Chemicals Lalanti

Xutting Truck Co.,

Inc.,

Chicago,

111.

Ventilation, See Air Conditioning Apparatus

Water Filters, See Filters Water Mixers and Temperature Regulators Foxboro Instrument Co., Foxboro, Mass. Fulton Sylphon Co., Knoxville, Tenn. Leonard Rooke Co., Inc., Providence, R. I.

Mason-Neilon Regulator Co., Boston, Mass. Taylor Instrument Co., Rochester, N. Y.

Water Softeners The Cochrane

Corp., Philadelphia, Pa.


346

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS The Permutit

Wm,

B. Scaife

Co.,

&

New

York, N. Y.

Sons Co., Oakmont, Pa.

Water Stills, See Stills Weighing Equipment Christian Becker, Inc., New York, N. Y. Eastman Kodak Co., Rochester, N. Y. (Laboratory Exact Weight Scale Co., Columbus, Ohio. Fairbanks, Morse & Co., Chicago, 111.

Fisher Scientific Co., Pittsburgh, Pa.

Toledo Scale Co., Toledo, Ohio.

Scales)


PART

D. CONVERSION TABLE OF FAHRENHEIT, CENTIGRADE, AND REAUMUR DEGREES F.


348

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS c-i

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350

PHOTOGRAPHIC CHEMICALS AND SOLUTIONS OOOOOOO^OOOCOC^O^ CO

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PHOTOGRAPHIC CHEMICALS AND SOLUTIONS CS

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PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

354

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INDEX OF FORMULAS BY PURPOSE iHi-Hi-iro

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PHOTOGRAPHIC CHEMICALS AND SOLUTIONS

356

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INDEX OF FORMULAS BY PURPOSE VT)

vO vO VD

357


INDEX Acetone in developers, 223 Acid rinse and acid hardening baths,

Citric acid, substitution for acetic in fixing

baths, 227

145

Acids, precautions when handling, 272 Acids, substitution of, in fixing baths, 227 Activator or alkali in a developer, 117, 122 Aerial fog in developers, 141 Airbells, 143 Alberene stone and slate, 67 Alkali in developers, substitution of, 218220

Alkalis on the skin, effect of, 270 Alloys for construction materials, 56

Aluminum sulphite stains, 232-234 Alums in fixing baths, substitution

of, 225 in developers, 222 in developers, 223 alum in the fixing bath, 226 carbonate in developers, 223

Amines, organic,

Ammonia

Ammonium Ammonium

Apparatus, materials for processing, table of, 51, 74, 75

Apparatus and methods of use, 15 Apparatus and supplies, manufacturers

of,

341

Asphalt concrete flooring over

vi'ood or

con-

hints on, 48

Coated metals, chemical resistivity of, 58 Compressed air, use of, for conveying solutions, 204

Concentrated developers, mixing, Continuous flow systems, 210 Conversion, of formulas Avoirdupois to metric, 6

210

British imperial liquid to metric, 7 I liter: 120 gallon conversion, 8 U. S. liquid to metric, 6 Cooling solutions, methods of, 89 Corrosion, electrolytic, of metals, 53 Covers for tanks, 70 Cyanide, precautions on handling, 271 Cyanide stain remover formula, 246

The

Darkroom, layout of small, 49 Deliquescence, and deliquescent chemicals, 191,

195

129

of,

Balances, types of, 16-17 Benches, construction of laboratory, 46 Bichromate treatment for cleaning trays, hangers, etc., 264 Bisulphite in the fixing bath, 225 Bisulphite, metabisulphite and sulphite in developers, 117 Bisulphite, reaction of carbonate with, 215 Blisters on films and papers, 166 Blue-green chromium stain, 252

Blue stains,

255 in developers, 119, 222 Boric acid in acid hardening fixing baths, 152, 227 British imperial measure, 6-7 Bromide in developers, 120, 224 Brown silver sulphide scum, 248 Brown stains from adhesives, 254 Buckets, rubber, for chemicals, 66

Borax

Caking of chemicals, 23 Calcium salts in water, 100 Carbon dioxide, action of,

on

certain

chemicals, 194

Carbon tetrachloride, precautions on handling, 271-273

Carbonate, sodium, types of, zz'^, Carbonate, substitution of sodium for potassium, 219 Carbonates in developers, 118 Centigrade, conversion of Fahrenheit temperatures to, 79 Centigrade, Fahrenheit, Reaumur degrees, conversion tables, 347 Chemical mixing room, diagram of a, 199-

Developer and ink stains, removal from hands, 266-267 Developer or oxidation stain, 238 Developer stain, local and general, 238, 240 Developer stain, removal of, 241-242 Developer troubles, 137 Developers, general hints on mixing, 123 Developers, index of, by purpose, 348 Developers, mixing less than 5 gallons, 123

Developers, mixing 5 to 500 gallons, 125 Developers, mixing 500 or more gallons, 126 Developers, multiple solution, 128 Developing agent and preservative, technique of mixing, 121

Developing agents, properties of common, 216-217

Developing agents, substitution of, 214 Development, fine-grain, 285 Development, (above 75째 F.) (24째 C), 180 Dichroic fog or green stain, 168, 249 Diluting solutions to volume, i Direct-Flo cooler, 94-95 Dissolving chemicals, 20 Distillation of water, methods of, 106 Double coated films, processing of, in hot weather, 185 Drying photographic materials at high temperatures, 190

Duplicating stained negatives, 241

Dust from powdered chemicals, precautions regarding, 274

Dye Dye

solutions, mixing, 177 stains, 254, 265, 268

Earthenware, glazed, 62

201

Chemical names and abbreviations, 5 Chemical treatment for purification water,

127

Desensitizers, how to mix, 144 Developer components, varying proportions

crete, 44

Automatic processing machines,

Cleaning photographic apparatus, 262 Cleanliness in handling solutions, general

Efflorescence of

no

Chemicals having harmful effect on photographic materials, 192 Chemicals, solubility of photographic, 338 Chemicals, transportation of, 202

Chrome alum fixing baths, 153-158 Chrome alum for potassium alum, Chrome alum hardener bath, 183 Circulating systems, 209

154,

227

191.

and

efflorescent

chemicals,

19s

Electrolytic corrosion of metals, 53 Elon, precipitation of insoluble base, 122 Elon vs. hydroquinone, rates of develop-

ment,

115

Enameled

steel, 58

Fabric membranes for waterproof floors, 42 Fabrics, white and colored, removal of stains from, 267-269


INDEX

359

Fading

Mackie line effects, 135 Manometers, uses of, 213

Fahrenheit, conversion of Centigrade temperatures to, 79 Farmer's reducer, 172 Faucets, piping, pumps, construction mate-

Mastic, material for

of silver images, factors determining, 2j6

rials for, 72

Ferric alum proportional reducer, 172 Fibrous materials, impregnated, 60 Filtering and clarifying solutions, 31 Filters, types of. 32,(7 Filtration of water, methods of, 107

155.

i)oint test,

floor 156

construction, 43

Membranes,

fabric, for waterproof floors, 42 Mctabisulphite, quantities of alkalis re(juired to neutralize, 218

Metal samples, testing corrosion resistance of. 53

Metaphosphate

for prevention

of

calcium

precipitates in developers, loi

Mixers, water, 87 Mixing room, layout of solution, 40

Fine-grain development, 285

Fixing Fixing Fixing Fixing Fixing

Melting

bath, substitution in the, 225

Molybdenum-stainless

bath troubles. 164 baths, technique of mixing, 14S-157

Monckhoven intensifier, 173 Monohydrated sodium carbonate,

baths, testing, 159 baths, properties and useful life

Mottle produced in developers, in fixing of,

baths,

steel, 56

223

142, 169

160

Flash lamps and flash powders. 274 Floor construction for chemical mixing rooms and darkrooms, 41

Nitre cake or sodium bisulphate, 228 Non-hardening fixing baths, 148

Flow meters, types of, 212 Fog in developers, methods

Opalescent stains, 234 Outlet, hard-rubber for storage tank, 197 Oxidation or develojicr stains, 238, 240, 262 Oxygen, action of, on certain chemicals,

of prevention

of. i3--"39

Formaldehyde-sulphite reaction, 120, 182 Formalin as a hardening agent in developers, 182-183

Formalin, hardener formula, 234 Formalin, precautions on handling, 272 Formula index, by purpose, 348 Fungus, slime, mold, etc., removal from tanks, 265

271

Glass, apparatus made from, 60 Glass-enameled steel, 58 Green stain from chrome alum, removal

of,

183 clips,

cleaning with acetic acid,

264

Hardener rinse baths, 146 Hardener solutions, mixing.

157

Heater, low pressure steam water, 85-86

Hot weather troubles,

187

green stain, scum, 189 reticulation, blisters, sulphur

sludge,

188

Hydrolysis of alkalis, 218 Hydrometers, value of, for testing. 12 Hydroquinone sulphonates in developers, 133

Hydrosulphite as a fogging agent, Hypo, rate of fixation, 149 test solution,

141

cals, 228

Ink and dye stains, 255, 266 Ink eradicator, for stain removal.

269

Iodide as a restrainer in developers, 224 Iodine-cyanide reducer, 173 Iron toning bath, 176 in developers. 119-131, 222 tropical developer (DK-is), 182

Lead acetate

for

59

prevention of sulphide

fog, 102

Life of developers, without use, with use, 132, 134

Life, useful, of fixing bath, 160

stain. 242

Persulphate reducer, 170 pH. of various alkalis in developers, 118 Phosphate treatment for cleaning trays, hangers, etc., 264 Photofinishers' chemical mixing room, 199 Piping, pumps, faucets, construction materials for, 72

for.

224

Preservative in developers,

116, 215

Pumps, 206 Pumps, piping, faucets, construction materials for. 72 in negatives, 114

Pyro stain

Pyro-staining developer, 244 scale of temperature, conversion table, 79, 347

Ice, dry, for cooling purposes, 92 Impurities in developing and fixing chemi-

Lacquered and painted metals, Laminated metals. 60

Permanganate

Reaumur

159

Hypo-alum toning bath, 173 Hypochlorite treatment, 265

Kodalk Kodalk

Paraformaldehyde in developers, 223 Parts, meaning of, 11 Paste, brown stains caused by, 254 Percentage solutions, definition of, 8 Permanganate reducer, 171

Porcelain and glazed earthenware, 62 Potassium salts, substitution of sodium

fog. dichroic. 187

Hypo

for,

214

Paraffined wood. 62

Gases and liquids, precautions on handling,

Hangers or

193

Paddles, mixing. 26 Painted and lacquered metals, 59 Para-aminophenol, substituting Elon

Recirculating system for automatic processing machines, 20 Recording thermometers, 83-85 Reducing or developing agent, 1:4 Refrigerating equipment. Deep tanks of 10 to 150 gallons capacity, 95

Large machines of

100 to 500 gallon capacity, 98 of 5 to 10 gallon capacity, 94

Tanks

Refrigeration, mechanical, 93 Replenishment of developers, 136 Restrainer or bromide in developers, 120 Restraining effect of developer reaction products. 134 Reticulation of gelatin, :8o Rinse baths, acid, 145 Rubber buckets, 66 Rubber, nitrocellulose and asphaltum materials. 62

Rubber-lined tanks,

64, 201


INDEX

360 Saturated solution, Scales, types of, 15

Scum on

Sulphites and bisulphites in developers, in

i

fixing baths, 117, 225

developers, on fixing baths,

138,

Scum, removal 263

Silver intensifier, 174 Silver stain, yellow, 245 Silver stains, removal from hands, 266 Silver sulphide deposits, removal of, from apparatus, 263 Silvery-white opalescent stains, 235 Sinks, construction of laboratory, 46 Siphons, 208 Skin irritation from metol and amidol, 274, 275

Slate and alberene stone, 67 Sludge, suction device for removing from developer, 35 Sludging of the fixing bath, 164 Soapstone (alberene stone) tanks, 67 Sodas, desiccated and crystal, 223 Sodium salts, substitution of potassium for, 224

Solubility, definition of, Solute, definition of, i

i

Solution conveyance, 203 Solution storage, small volume, large vol-

ume.

hydroqui-

di.-)

Sunlight, action

of,

on certain chemicals,

195-198

Superhardener for bromide papers, 169 Swelling and contraction of films during processing, 179

Sylphon water mixer, 88 Systems of measurement-units volume, 2

rials for, 72

images, usefulness and control

of

mass and

Tank, cooling installation for a deep, 96 Tanks, deep, for motion picture and photofinishing work, 69

Temperature coefficient, 80 Temperature conversion table, 347 Temperature measurement and control, 79 Temperatures, handling solutions at high, 178.

Testing fixing baths for films, for prints, 159, 162

Testing a mixed developer, 132 Thermometers, types of, 82-84 Thiourea stain remover formula, 252 Transportation of chemicals, 202 Trays, small tanks, etc., materials for construction

of.

68

Trisodium phosphate,

196, 198

Solvent, definition of, i Solvent fog in developers, 141 Sprockets, tubes, idlers, construction mate-

131.

ttse

in

developers,

222

Troubles, fixing bath, 164

Troughs for reel development, Two-bath developers, 129

72

of,

Vegetable matter, stains from, 255

242-244

Stain

and

(mono-

Sulphur stains, 234

of, 40

Sea water, suitability of, for washing, 112 Silver deposits, removal of, from apparatus,

Stain

Sulphonates none, 133

108

removal from hands and clothing,

266-267

Stain, yellow in developers, 142 Stainless steel, 18-8 molybdenum mixing tanks, 205 Stainless steels, properties of, 56 Recommendation for various types of

equipment

Welds

in.

7;}.

(table), 74-75 76

Stains, classification table, 258 Steam water heater, 85-86 Stirring solutions, methods of, 24-28

tion, etc., on, 100-106 of a

338

181

140

Sulphite in developers, 116 Sulphite, sodium, types of. 224 Sulphite, solvent action of, 116

163

87

chemical analysis

of the. 112

Storage room for chemicals, rgi Substitution of chemicals, 214 Sulphate, use of sodivim, in developers.

Sulphide fog, prevention and removal,

Water mixers,

Waterproofing floors for chemical mixing rooms and darkrooms. 41 Water softening, methods of, 110 Water supply, effect of. development, fixa-

Water supply, value

Stirring, theory of, 28 Stock solutions. 13 Stock solutions of chemicals, solubility of,

Sulphide stain, yellow silver, 246 Sulphide test for fixation of prints, Sulphide toning bath, 176

Wash water temperature, importance of, 99 Water, impurities in, 100 Water heater, low pressure steam, 85-86

102,

Weighing devices, types of. 14 Weighing and measuring, 18 Welding stainless steels, 76 White stains, 232 Winchester measure, 7 Wood, as a construction material,

61

Yellow silver stain, 245 Yellow silver sulphide stain. 246 Yellow stain in developer, 142 Yellow stains on glossy prints, 253 Yellowish-brown iron rust stains.

248

Yellowish-white opalescent stains, 234 Yellowish-white stains, 236 Zeolite treatment for softening water, 110


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Photographic Chemicals and Solutions  
Photographic Chemicals and Solutions  

by John Ickeringill Crabtree and G.E. Matthews, 1938

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