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MODERN DEVELOPERS

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For the reasons already given, it is preferable to make up amidol developers only in the quantity required for a day's use. Typical formulas are as follows: For plates and films.-Water, 10 ounces; sodium sulphite (cryst.), 1 ounce, or dry,~ ounce; diamidophenol (Amidol,etc.), 40 grains. Restrain with potassium bromide (xo per cent solution) as needed. Underexposure can be helped by the addition of IO per cent sodium sulphite solution as indicated. For bromide papers: Water, 20 ounces; sodium sulphite (dry), 320 grains; potassium metabisulphite, I2o grains; diamidophenol (Amidol, etc.), 6o grains; potassium bromide, s grains. (Dilute for gray tones). For lantern-slide plates: Water, IO ounces; sodium sulphite (dry), ISO grains; diamidophenol, so grains; potassium bromide, 3 grains. For tank development with Dianol: Water, 6o ounces; sodium sulphite (dry), I8o grains; potassium bromide (Io per cent solution), ~ ounce; Dianol, 4S grains. Develop 30 minutes at 6S째 Fahr. This developer, said to be benzyiDuratol paramidophenol, was introduced by Schering as a universal developer, to be used in combination with hydroquinone. It won great favor upon its first introduction (I9II-I2) but is no longer obtainable. Duratol is a soft-working developer of the metol class, especially suitable for instantaneous work. It is stable in solution, free from tendency to fog or stain, docs not injure the hands, and has unusual developing power, i.e. it is not quickly exhausted, in which it surpasses other derivatives of paramidophenol. A typical formula is: Hot water, 32 ounces; Duratol, IS grains; sodium sulphite (dry), I ounce; sodium carbonate (dry), I~ ounces; hydroquinone, 7S grains. Duratol-solution was a concentrated form of this developer, requiring only dilution with water to be ready for use. For normal exposure, it was diluted with I6 parts of water; for underexposure, with 30 to 40 parts; for overexposure, with 8 to IO parts of water, and the addition of potass. bromide. J'ormulaa

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...

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...

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