172 PHOTOGRAPHIC FACTS AND FORMULAS 
some of the strontium bromide with anhydrous calcium 
chloride, thus using in the above: 
Strontium bromide, anhydrous 10.6 g 81.3 gr. 
Calcium chloride, anhydrous 3.3¢ 25.4 gr. 
If a still harder working paper is required, replace the calcium 
salt by uranyl chloride, 10 g (768 gr.). All these papers tone 
well in the usual baths, and lose but little in the fixing bath. 
Manipulation—The phosphate and bromide papers are 
used in the same way as ordinary printing-out papers. But, 
in consequence of their high sensitiveness, they should be 
manipulated in a yellow light, and extreme care should be 
taken when examining the prints during printing, otherwise 
a tint will be obtained over that portion of the paper exam- 
ined. They both tone well either in the separate or combined 
baths, but are specially suitable for sepia tones by platinum 
toning. 
