186 PHOTOGRAPHIC FACTS AND FORMULAS 
must be taken not to develop too far, and development should 
be stopped when the details in the high lights just begin to 
show. A stop bath of 10 per cent of potassium bromide or 
1 per cent glacial acetic acid should be used, the prints thor- 
oughly washed, and then toned in the ususal way. 
Disco (DEFENDER) PRINTING-oUT PAPER.—Print two or 
three shades darker than is desired in the final print. Wash 
in five or six changes of water before toning, and tone in the 
following, keeping the prints moving: 
Gold chloride solution 25 ccm 1 oz. 
Water 1000 ccm 40 oz. 
Add enough borax to turn red litmus paper blue. The above 
gold chloride solution is made by dissolving a 15-grain tube 
of gold chloride in 15 0z. or 425ccm of water. When the 
desired tone is attained, transfer prints direct to a 4 per cent 
solution of hypo. 
EASTMAN Sotio Parer.—Wash prints in 5 or 6 changes 
of water before toning. Tone in a plain gold bath, using 
044g (lgr.) to 1000ccm (480z.) water. Neutralise by 
adding a few drops at a time of saturated solution of borax, 
sodium bicarbonate or sal soda. Test with red litmus paper. 
When toned, immerse prints in running water, or: 
Common salt 8g loz, 
Water 1000 ccm 128 oz. 
Fix not less than 10 minutes in: 
Hypo 100 g 13 oz. 
Water 1000 ccm 128 oz. 
Solio hardener 4 ccm YZ oz. 
The Solio hardener is made as follows: 
Aluminum chloride 250 ccm 3 02. 
Sodium bisulphite 208 g 214 02. 
Water 1000 ccm 12.07, 
Or the following may be used: 
