DEVELOPERS 109 
Boil, allow to cool for 5 minutes, and add a few crystals of 
potassium metabisulphite; then add: 
Paramidophenol hydrochloride 50¢ 385 gr. 
Potassium metabisulphite 150))))2\0z)) 192) er: 
Stir until dissolved. Then make a solution of : 
Caustic soda 215i g 3Y oz. 
Water 500 ccm 834 oz. 
and add with constant stirring about 340 to 350 ccm (6 oz.) 
to the paramidophenol solution. At first a precipitate of the 
paramidophenol base is formed, but, as more caustic soda 
is added, this dissolves. Enough soda solution should be 
added to nearly dissolve the precipitate; then add: 
Water to inake 1000 ccm 16 oz. 
Bottle and allow to cool. Should any paramidophenol crys- 
tallise out, more soda must be added to nearly dissolve it. It 
is very important to leave some undissolved. For use mix 1 
part with 10 parts water with some bromide for plates, and 
with 40 parts water for papers. 
Liquid developers consisting of paramidophenol and an 
alkali are marketed under such names as rodinal, azol, activol, 
citol, paranol, paramol, certinal, kalogen, etc. 
PARAPHENYLENDIAMINE, for fine-grained images (Lumi- 
ére & Seyewetz).—The following gives a finer grain image 
than most developers: 
Paraphenylendiamine 10g VANES: 
Sodium sulphite, dry 60 g 460 er. 
Water 1000 ccm 16 oz. 
PYROCATECHIN OR Kacuin.—Also called Elconal. 
A. Pyrocatechin lg 8 gr. 
Water 1000 ccm 16 oz. 
B. Potassium carbonate 200 g fez: 
Water 1000 ccm D OZ: 
For use mix 10 parts A with 1 part B. Gives brownish 
