194 PHOTOGRAPHIC FACTS AND FORMULAS 
Tartaric acid may be used instead of the citric, and darker 
brown tones are obtained. Immerse the paper in the warm 
solution and dry. Sensitise by brushing over with either of 
the following solutions: 
Silver nitrate 120 g 922 gr. 
Citric acid 50 g 384 gr. 
Glycerine 50 ccm 384 min. 
Water 1000 ccm 16 oz. 
DS ay 
Silver nitrate 120g 922 gr. 
Ammonia q. S. q.S. 
Water 500 ccm 8 oz. 
Use enough ammonia to form a clear solution, and then add: 
Lactic acid, pure syrupy 50 ccm 384 min. 
Water to 1000 ccm 16 oz. 
Greater contrasts can be obtained by adding a little 5 per 
cent solution of potassium bichromate. A more rapid paper 
is obtained with the following: 
768 gr. 
384 gr. 
384 min. 
16 oz. 
512 gr. 
5 oz. 
12.3 gr. 
256 gr. 
Silver nitrate 100 g 
Uranium nitrate 50 g 
Lactic acid 50 ccm 
Water 1000 ccm 
The following gives sepia tones, but the stock solution will 
not keep: 
Ammonio-citrate of iron, green 66.6 g 
Water 333 ccm 
Potassium bichromate l6g 
Dissolve, and add: 
Silver nitrate 33.32 
Water 667 ccm 
11 oz. 
After printing, this paper should be immersed in a 1 per cent 
solution of oxalic acid, then washed, and fixed in a 2 per cent 
hypo bath. 
