Page 14

THE PHOTo-MINIATURE to the para form-metol), being a patented mixture, probably as seen in Fig. 16 -QH



II '-../


(15) Glyoin

It is characteristic of the benzene Naphthalene groups that they readily link themselves Group: Eikonogen together, giving compounds of great Diogen, etc. complexity from which other derivatives

useful as developers may be obtained. Thus, by linking two benzene rings, as seen in Fig. I 7, we get naphthol (C.oHa) from which eikonogen (Fig. 18) and diogen (Fig. 19) are derived.

rr1 '-../'-/

m~H m~ HS03

(17) Naphthol



(18) Eikonocen



119) Diogen

Or we may imagine the two rings linked as in Fig. 20, representing the compound diphenyl (C••H.o), from which the Agfa developer Diphenal is obtained, as seen in Fig. 21.


NH 3


(20} ~henyl


(21) Diphenal

-NH 2

This graphic survey of the substitu-

What We Have tion possibilities of the benzene comLearned .

pound may well suffice to give us a practical notion of the origin of some of our modern developers. As we know, most of them were patented products imported from Germany, and, as our chemists

Modern Photographic Developers  

A Practical Handbook to the New Developers Telling What They Are and How to Use Them with Reliable Formulae by The Photo Miniature, January...