SILVER PRINTING PROCESSES 17s 
Add this in small quantities to the collodion, shaking thor- 
oughly after each addition, and add: 
Ether 320 ccm 5 oz. 
Glycerine 13 ccm 100 min. 
Alcohol 13 ccm 100 min. 
The addition of calcium chromate is not necessary with this 
emulsion, as it gives sufficiently brilliant prints without. This 
paper is specially suitable for very brief exposures and devel- 
opment with a metol-citric acid developer. 
SILVER BROMIDE PRINTING-OUT PAPER.—This gives a very 
rapid-printing paper with long scale of gradation: 
Citric acid 100 g 768 gr. 
Alcohol 400 ccm 6Y, oz. 
Dissolve, and add: 
Collodion, 3% 5000 ccm | 80 oz. 
Then add: 
Strontium bromide, anhydrous 16g [23 )en: 
Glycerine 20 ccm 154 min. 
Alcohol 30 ccm 230 min. 
After mixing, add: 
Silver nitrate 100 g 768 gr. 
Hot water q. S. q. S. 
Alcohol 400 ccm 634 oz. 
Dissolve the silver in as little water as possible, then add the 
alcohol, and add to the bromised collodion in small quantities, 
shaking well after each addition. Finally, add: 
Ether 800 ccm 13 oz. 
Allow the emulsion to stand a few minutes, and filter through 
glass wool. This emulsion must be mixed by orange light. 
It is about three times faster than commercial chloride papers 
and tones well in the usual baths, but is only suitable for 
contrasty negatives. The addition of calcium chromate gives 
more contrast. Even better results are obtained by replacing 
