242 PHOTOGRAPHIC FACTS AND FORMULAS 
Sodium sulphite, dry 50 g 384 gr. 
Water 1000 ccm 16 oz. 
B. Sodium carbonate, cryst. 200 g 3 1/5 oz. 
Water 1000 ccm 16 oz. 
C. Schlippe’s salt 10g 77 gr. 
Water 1000 ccm 16 oz. 
For use mix 2 parts A with 1 part B, and for sepia tones add 
2 per cent C; for warm brown tones add 4 percent C. 
Toning with mercury sulphides.—In this method the varia- 
tion of colour depends on the addition of more or less mer- 
cury salt to the image (Bennett). Two stock solutions are 
required for the bleaching bath: 
A. Ammonium bromide Lig 85 gr. 
Potassium ferricyanide 35 g 269 gr. 
Water 1000 ccm 16 oz. 
B. Mercuric chloride 28 ¢ 215 oF) 
Potassium bromide 28 g 215 on: 
Hot water 1000 ccm 16 oz. 
And two stock solutions for the toning bath: 
I. Sodium sulphide 330 g 5 1/Sag: 
Sodium sulphite, dry 50 to 65 g 385 to 500 gr. 
Water 1000 ccm 16 oz. 
II. Schlippe’s salt 10g (7 /8E: 
Water 1000 ccm 16 oz. 
The following table gives the colours obtainable with the 
various baths: 
Bleacher Toning bath 
Black AL iy By I I 
Brown black AS 2: B, 1 iE 
Deep brown A, 3;B,1 I 
Dark brown A Stoi7 > B, 1 I 
Deep warm brown A I 
Reddish brown A Lae 
rere” 
