SULPHIDE TONING 235 
A. Hypo 125¢ 2 oz. 
Potash alum 31g Y, oz. 
Hot water 1000 ccm 16 oz. 
B. Silver nitrate, 10% sol. 10 ccm 77 min. 
Salt, 10% sol. 10 ccm 7/7 min. 
As soon as A has cooled down, add B with constant stirring. 
The best temperature is 31° C. (88° F.), and toning takes 
from 15 to 30 minutes. 
Alum-gold-hypo (Artura)— 
Hypo 62.5 g 1 oz. 
Potash alum 15.5¢ YA oz. 
Sodium phosphate ibeyesy ces 4 oz. 
Hot water 1000 ccm 16 oz. 
Dissolve the salts in the order given. Add, when the solution 
is cold: 
Silver nitrate, 10% sol. 10 ccm 77 min. 
Potassium bromide, 10% sol. 10 ccm 77 min. 
Finally, add: 
Gold chloride, 1% sol. 13 ccm 100 min. 
The working temperature should be 35° to 39° C. (95° to 
Oe At) 
When hot toning baths are used, the prints should be 
allowed to cool before washing; otherwise blisters are very 
likely to form. 
Colloidal sulphur (Lumiére).— 
Hypo 125'¢ 2 2. 
Hot water 1000 ccm 16 oz. 
Dissolve, and add: 
Yellow dextrine, 50% sol. 250ccm 4 oz. 
And, shortly before use, add: 
Hydrochloric acid, pure 50 ccm 384 min. 
The bath will not keep more than about 2 hours. Prints 
should be immersed in the bath at a temperature of 18° to 
