98 PHOTOGRAPHIC FACTS AND FORMULAS 
I. Potassium oxalate 125 ¢ 2 oz. 
Potassium citrate 42¢ Y, oz. 
Water 1000 ccm 16 oz. 
This gives cold tones. 
II. Citric acid 333 g 51/3 a, 
Ammonium carbonate 250 g 4 oz. 
Water 1000 ccm 16 oz. 
Gives warm tones. 
III. Citric acid 500 g 8 oz. 
Ammonium carbonate 166 g 2 2/3 ae. 
Water 1000 ccm 16 oz. 
Gives extra warm tones. 
IV. Ferrous sulphate 333 g 5 1/3 02: 
Sulphuric acid 12.5 ccm 96 min. 
Water 1000 ccm 16 oz. 
For use add 1 part of IV to 3 parts of I, II, or III. Another 
modification is: 
Citric acid 250 g 4 oz. 
Magnesium carbonate 157 g 24 02. 
Water 1000 ccm 16 oz. 
This can be used instead of I, II, or III given above. 
Should any calcium oxalate be precipitated in the gelatine, 
a weak hydrochloric acid bath, about 1 per cent, will remove 
the precipitate. 
Giycin.—This is a slow-working very clean developer 
giving images of a neutral grey colour, and is very suitable for 
stand development. 
Glycin paste (Hibl).— 
Sodium sulphite, dry 125 ¢ 1% oz. 
Warm water 400 ccm 4 oz. 
Glycin 100 g 1 oz. 
