284 PHOTOGRAPHIC FACTS AND FORMULAS 
allow the paper to dry at normal temperatures. The devel- 
oper should be: 
Potassium oxalate lg 16 gr. 
Potassium chloroplatinite lg 16 gr. 
Potassium phosphate 0.5 ¢ 8 gr. 
Water 12 ccm 192 min. 
Glycerine 6 ccm 96 min. 
Place the print face up on a sheet of glass, and paint with 
the above, using a broad flat brush, and working as quickly 
as possible. For the above area of paper about 20ccm 
(154 min.) of developer will be required. 
For line work or black and white work, this process 1s 
very suitable, and the following sensitiser should be used: 
Lead-iron sol. 7 ocem 120 min. 
Potassium chloroplatinite 
sol. 0.375 ccm 6 min. 
Neutral potassium chromate, 
1% sol. 0.375 ccm 6 min. 
Water 7.5 ccm 120 min. 
The above quantity is sufficient for 5940 qcm (870 sq. in.). 
The best developer for this work is: 
Potassium chloroplatinite 12 ccm 84 min. 
Glycerine 50 ccm 350 min. 
Water 450 ccm 8 oz. 
Thirty ccm (1 0z.) should be used for the above area. Actu- 
ally, this process is as cheap as or cheaper than any silver 
printing process. The acid baths must be used with all 
papers as already described. 
PLATINUM PRINT-oUT PapER.—It is possible to prepare 
platinum paper that will print out in the printing frame, but 
it does not keep well, and the results are greatly dependent 
on the humidity of the paper at the time of printing. If too 
dry, only the shadows will appear; while if too damp, flat 
