Pyrocatechin Formula
Description
This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
Pyrocatechin Formula
Pyrocatechin...... 2 parts
Sulphite of soda,
crystals......... 2.5 parts
Water............ 100 parts
Solution B Carbonate of soda. 10 parts
Water............ 100 parts
Before using mix 20 parts of Solution A, and 0.5 part of Solution B.
Metol Quinol
Water............. 10 ounces
Metol............. 7 grains
Sodium sulphite, crystals, pure..... 0.5 ounce
Hydroquinone..... 30 grains
Sodium carbonate, dessicated........ 200 grains
(or 400 grains of crystallized carbonate).
Ten per cent bromide of potassium solution, about. . . 10 drops
Amidol Formula
Water............ 4 ounces
Sodium sulphite, crystals, pure ... 200 grains
Amidol, about..... 20 grains
Ten per cent bromide of potassium solution, about.......... 5 drops
If the blacks are greenish, add more amidol; if whites are grayish, add more bromide of potassium.
Hypo-Acid Fixing Bath
Hypo............. 16 ounces
Water............. 64 ounces
Then add the following hardening solution:
Water. ............ 5 ounces
Sodium sulphite, crystals.......... 0.5 ounce
Commercial acetic acid (containing 25 per cent pure acid)............ 3 ounces
Powdered alum.. ... 0.5 ounce
Amidol Developer
Amidol......... 2 grains
Sodium sulphite. .. . 30 grains
Potassium bromide. 1 grain
Water............. 1 ounce
With a fairly correct exposure this will be found to produce prints of a rich black tone, and of good quality. The whole secret of successful bromide printing lies in correctness of exposure. It is generally taken for granted that any poor, flat negative is good enough to yield a bromide print, but this is not so. A negative of good printing quality on printing-out paper will also yield a good print on bromide paper, but considerable care and skill are necessary to obtain a good result from a poor negative. The above developer will not keep in solution, and should be freshly prepared as required. The same formula will also be found useful for the development of lantern plates, but will only yield blacktoued slides.
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