PRINTING-OUT PAPERS 179 
with the separate toning and fixing baths. An excellent 
formula and method of mixing was given by Valenta: 
Hypo 200 g 314 oz. 
Ammonium sulphocyanide 25g 192 er. 
Lead nitrate 10g 77 gr. 
_ Alum 20 g 154 gr. 
Water 500 ccm 8 oz. 
Dissolve the hypo in about three-fourths of the water, and 
add the sulphocyanide; then add the alum and lead nitrate 
dissolved in the remainder of the water. Heat the mixture 
to 50° C. (122° F.) for 10 minutes, allow to cool, and filter. 
For use, mix: 
Stock solution 500 ccm 8 oz. 
Water 500 ccm 8 oz. 
Gold chloride 08¢ 6.1 gr. 
The prints must be well washed prior to toning. 
Fix1nc.—The normal fixing bath, after any separate ton- 
ing bath, should be a 10 per cent solution of hypo, or an 
alkaline bath may be used, such as: 
Hypo 100 g LY oz. 
Sodium carbonate, dry 6.25 g 48 gr. 
Salt 12:5) ¢ 96 gr. 
Water 1000 ccm 16 oz. 
Or: 
Hypo 100 g 1Y4 oz. 
Sodium sulphite, dry WAS) 96 gr. 
Salt 12.5 ¢ 96 gr. 
Water 1000 ccm 16 oz. 
Keep the prints moving in the fixing bath for 10 minutes, 
and then wash. Occasionally, a second fixing bath is used as 
conducing to greater permanency. 
The tone of the prints is to a great extent dependent on 
the quantity of gold per area, although this, naturally, varies 
