Part 341

Water 32 ounces Sodium carbonate 4 (10) ounces

If preferred, stock solutions B and C can be made by hydrometer, instead of by weight as above. The solutions will then show:

Solution B

Sodium sulphite 40

Solution C

Sodium carbonate 75

Or if potassium carbonate is preferred instead of sodium:

Solution C

Potassium carbonate 60

For standard formula for dry plates and films, mix

Solution A 1 part Solution B 1 part Solution C 1 part Water 7 parts

For strong negatives (for aristo-platino):

Solution A 1 1⁠/⁠2 to 2 parts Solution B 1 part Solution C 1 part Water 4 to 4 1⁠/⁠2 parts

For tank development:

Solution A 1 part Solution B 1 part Solution C 1 part Water 35 parts

For developing paper:

Solution A 2 parts Solution B 2 parts Solution C 1 part

The reading of the hydrometer for stock solutions is the same whether dried chemicals or crystals are used. No water is used.

«Pyrocatechin-Phosphate Developer.»—

Solution A

Crystallized sulphite of soda 386 grains Pyrocatechin 77 grains Water 8 ounces

Solution B

Ordinary crystal phosphate of sodium 725 grains Caustic soda (purified in sticks) 77 grains Water 8 ounces

Mix 1 part of A with 1 part of B and from 1 to 3 parts of water. If the exposure is not absolutely normal we recommend to add to the above developer a few drops of a solution of bromide of potassium (1.10).

«Pyrocatechin Developer» (One Solution).—Dissolve in the following range:

Sulphite of soda crystallized 25 1⁠/⁠2 drachms Caustic soda (purified in sticks) 3 1⁠/⁠2 drachms Distilled water 14 ounces Pyrocatechin 308 grains

The pyrocatechin must not be added until the sulphite and caustic soda are entirely dissolved. For use the concentrated developer is to be diluted with from 10 to 20 times as much water. The normal proportion is 1 part of developer in 15 parts of water.

«Vogel’s Pyrocatechin Combined Developer and Fixing Solution.»—