290 PHOTOGRAPHIC FACTS AND FORMULAS 
C. Potassium citrate, sat. sol. 
D. Potassium sulphocyanide 100 g 768 gr. 
Water 1000 ccm 16 oz. 
For use mix in the following order: A 140 parts, B 140 parts, 
C 24 parts, D 50 parts. As this is nothing more than a 
modification of the copper toning process for bromides, pre- 
sumably the same class of tones will be obtained. 
Biur Prints spy DEVELOPMENT (Waverley) .— 
Potassium oxalate, 1:3 sol. 22 ccm 170 min. 
Potassium ferricyanide, 
10% sol. 9 ccm 70 min. 
Glycerine 55 ccm 42 min. 
Water 1000 ccm 16 oz. 
Printing must be carried deeper than usual. The prints as- 
sume a green tone in the developer and only turn blue in the 
acid baths. 
PRINT-OUT SEPIA PapER.—Another method of obtaining 
pure brown tones is by the admixture of some palladium salt 
with the sensitiser, potassium chloropalladite in 10 per cent 
solution being used. The paper should preferably be sized 
with arrowroot, and the sensitiser is: 
Potassium chloropalladite sol. 4ccm 65 min. 
Sodium ferric oxalate 6 ccm 97 min. 
Lead-iron sol. 2 ccm 32 min. 
Water 3to6ccm 45 to 96 min. 
The image is so slightly visible that an actinometer should be 
used. Development should be effected with steam or by 
pressing the prints between damp blotting papers. 
Another method is by the use of mercury (Pizzighelli) : 
A. Potassium chloroplatinite 10 ¢ 70 gr. 
Water 60 ccm 420 min. 
B. Sodium ferric oxalate 40 g 280 gr. 
Gum arabic 40 g 280 gr. 
