20 PHOTOGRAPHIC FACTS AND FORMULAS 
Old fixed-out dry plates, or negatives freed from their 
images by reduction, may also be used by soaking in the 
above dye solutions minus the gelatine, that is, using water 
instead of the gelatine solution, for half an hour, then rinsing 
and drying. Or soak one plate in 3 per cent solution of 
naphthol yellow, and another in 0.9 per cent solution of 
methyl violet for half an hour, rinse, dry and bind together. | 
The following was suggested by Haberkorn: 
Gelatine 60 ¢ 460 er. 
Water 1000 ccm 16 oz. 
Soak for 30 minutes, melt on water bath, and add: 
Blueish acid green I5¢ li Siar: 
Then add: 
Tartrazine 0.18 g 13.8 gr. 
Naphthol green 0.4¢ 3.1 ee, 
Stir well and filter while hot. To every 100 qcm allow 7 ccm, 
or 750 minims per 100 sq. in. Bind two such screens together, 
and coat one with matt varnish, or use tissue paper between; 
a sheet of ground glass placed between the light and the 
screen absorbs some of the heat. 
NON-ACTINIC PAPER.—Soak the paper in: 
Tartrazine 10 ¢ iit. 
Rhodamine lg 7./ gr. 
Water), >) 500 ccm 8 oz. 
Alcohol 500 ccm 8 oz. 
The quantity of rhodamine may be increased at will, when a 
deeper coloured paper will be obtained. The above paper is 
safe for rapid ordinary plates. Translucent vegetable parch- 
ment paper was also suggested. This was to be immersed 
for 5 minutes in a warm 10 per cent solution of gelatine and 
dried, then stained up in one of the following baths: 
A, Tartrazine  - 2 per cent solution 
B. Chrysoidine 0.1 per cent solution 
