244 PHOTOGRAPHIC FACTS AND FORMULAS 
Sulphide and Schlippe’s salt Variation of colour may be 
obtained by combining sodium or ammonium sulphide with 
Schlippe’s salt (Bishop). Ten per cent solutions of sodium 
sulphide and Schlippe’s salt should be made, or the com- 
mercial solution of ammonium sulphide may be used. For 
red-brown tones mix: 
Sulphide solution 25 ccm 192 min. 
Schlippe’s salt solution 75 ccm 576 min. 
Water 1000 ccm 16 oz. 
For warm brown: 
Sulphide solution 50 ccm 384 min. 
Schlippe’s salt solution 50 ccm 384 min. 
Water 1000 ccm 16 oz. 
For brown tones: 
Sulphide solution 75 ccm 576 min. 
Schlippe’s salt solution 25 ccm 192 min. 
Water 1000 ccm 16 oz. 
Carmine or red chalk tones.——These can be easily procured 
by treatment of a sulphide toned print with gold sulpho- 
cyanide: 
Gold chloride 2.3¢ 15 gr. 
Ammonium sulphocyanide 23g 150 gr. 
Water 1000 ccm 16 oz. 
The following (Blake-Smith) acts better: 
A. Gold chloride lg 1bee 
Water 225 ccm 7 OZ. 
B. Thiocarbamide O25¢ 23; OF: 
Water 1000 ccm 16 oz. 
C. Sulphuric acid 10 ccm 77 min. 
Water 1000 ccm 16 oz. 
For use mix 1 part each of A, B and C with 10 parts water. 
Allow the action to continue until the deepest shadows are 
toned. 
ts 
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