SULPHIDE TONING 241 
Hot water 1000 ccm 16 oz. 
When cold, add in small quantities with constant stirring, 
ammonium sulphide sufficient to form a deep orange solu- 
tion. For use mix: 
Stock solution 100 ccm 7/0 min. 
Ammonia 10 ccm 7/ min. 
Water 1000 ccm 16 oz. 
If the whites of the prints are stained yellow, immerse for a 
short time in a 3 per cent solution of ammonia, and wash 
thoroughly. This gives excellent results with the bichromate 
bleaches. 
Sodium sulphostannate may be prepared as follows: 
Sodium sulphide, pure 30 g 230 gr. 
Water 1000 ccm 16 oz. 
Stannic sulphide 0g 538 gr. 
Dissolve the sodium salt in about one-fourth of the water, 
add the tin salt, and heat gently with constant stirring until 
dissolved; then dilute to bulk. Stannic sulphide is known | 
also as tin disulphide, or bisulphide, or mosaic gold. One 
part of the above solution should be diluted with 9 parts of 
water for use. 
Sulphides plus developer—This method gives somewhat 
darker tones, as some black metallic silver is probably formed 
with the sulphide. The prints should be bleached as usual 
(Greenall), and then treated with the following: 
Metol lg 7/7 gr. 
Potassium carbonate 1325s 100 gr. 
Sodium sulphide, 1% sol. 3to5ccm 23 to 40 min. 
Water | 1000 ccm 16 oz. 
This gives a warm black, which varies with increase of the 
sulphide. 
Valenta’s method requires three stock solutions: 
A. Pyrocatechin 20g 154 gr. 
