272 PHOTOGRAPHIC FACTS AND FORMULAS 
2. Ferric ammonio-citrate, brown 12g 6 gr. 
Ferric oxalate 60 g . 36 er 
Potassium oxalate 60 g 30 gr. 
Cupric chloride 12¢g 6 gr. 
Gum arabic 20 g 10 gr. 
Water 1000 ccm 1 oz. 
3. Ferric ammonio-citrate, brown 50g 25 Sm, 
Ferric oxalate 30 g iSiem 
Potassium oxalate 70g 35.e1 
Cupric chloride l6g 8 er. 
Oxalic acid 30 g 15 en. 
Silver nitrate 30 g 15 gr. 
Gum arabic 20 g 10 gr. 
Water 1000 ccm 1 oz. 
Add potassium bichromate solution, 1:48, as desired. 
In preparing these solutions, mix in the above order, leave 
for 24 hours in the dark, and filter through cotton. Print 
faintly, and develop in: 
Silver nitrate 80 g 40 gr. 
Citric acid 20 g 10 gr. 
Oxalic acid l6g 8 gr. 
Water 1000 ccm 1 oz. 
Add sodium phosphate 3g (1% gr.) for blue-black tones. 
For use mix 1| part with 7 parts water. Fix in: 
Hypo 3to4g 24to 32 oz. 
Water 1000 ccm 16 oz. 
For brown, blue-green, and other colours: 
A. Ferric ammonio-citrate, green /0¢ 35 gr. 
Ferric oxalate l6g 8 gr. 
Potassium oxalate I2¢ 6 gr. 
Oxalic acid 44¢ 22 gr. 
Uranium nitrate 40 ¢ 20 er. 
Gum arabic 20g 10 gr. 
