PEATINOTY EE 283 
longer, in running water or several changes of water. Then 
fix in: 
Hypo 125 ¢ 6 oz. 
Water 1000 ccm 48 oz. 
for 15 minutes. Finally, wash in running water for 45 
minutes or in about 12 changes of water. The water used 
for the clearing bath must be free from lime. To free water 
from lime, dissolve oxalic acid 0.5 g (15 gr.) in 75 oz. (1000 
ccm). Allow to stand for some hours, and decant from the 
precipitate. 
THE PLATINUM-IN-DEVELOPER PRoceEss.—A variation of 
the platinotype process consists in using either no, or very 
little, platinum in the sensitiser, and adding it to the devel- 
oper. For this arrowroot size gives the best results, and the 
paper should not be highly sized. The sensitising solution 
may be one‘of the following: 
A. Lead-iron sol. 5 ccm 80 min. 
Mercuric chloride, 5% sol. 0.2 ccm 3 min. 
Water 3to6ccm 48 to 92 min. 
B. Lead-iron sol. 5 ccm 80 min. 
Potassium chloroplatinite sol. 0.5 ccm 8 min. 
Water 3to6ccm 48 to 92 min. 
C. Lead-iron sol. 5 ccm 80 min. 
Potassium chloroplatinite sol. 0.3 ccm 5 min. 
Sodium chloroplatinate sol. 0.4 ccm 6.5 min. 
Water 3to6ccm 48 to 92 min. 
D. Lead-iron sol. 5 ccm 80 min. 
Sodium chloroplatinate sol. 0.8ccm 13 min. 
Water 3to6ccm 48 to 92 min. 
A and B are suitable for normal negatives; C gives greater 
contrast ; and D should be used for very soft negatives. The 
area of paper is as previously stated. It is preferable to 
