352 PHOTOGRAPHIC FACTS AND FORMULAS 
film must be burnt in after development. 
INKING-UP LINE PRINTs oN Zinc.—Use photo-transfer 
ink, thinned down with very little turpentine, and apply with 
compo or fine nap leather roller. 
DeEvELOPING LINE Prints.—Immerse the plate in water, 
to which a few drops of ammonia have been added, and rub 
with swab of absorbent cotton. 
Harp ENAMEL FOR ZINC.— 
Fish glue 650 ccm 
Fresh white of egg 130 ccm 
(Or dried albumen) 92¢ 
Ammonium bichromate I5¢ 
Ammonia 15 drops 
Water 1000 ccm 
10% oz. 
2 OZ. 
70 gr. 
115 gr. 
10 drops 
16 oz. 
Beat the albumen to a froth and mix in the glue and again 
beat up, allow to stand eight hours, then dissolve the bichro- 
mate, then add the ammonia and filter through absorbent 
cotton. The following gives a much tougher film: 
i: 
Fish glue 187.5 ccm 
Belting cement, Le Page’s 93.75 ccm 
Ammonium bichromate 15.6¢ 
Albumen 187.5 ccm 
Ammonia 7.8ccm 
Water 1000 ccm 
. Le Page’s belting cement 312.5 ccm 
Chromic acid 2.85 g 
Ammonia 11 ccm 
Water 1000 ccm 
Pure rock candy 68 g 
Ammonium bichromate 34 g 
3 02. 
1Y4 oz. 
120 gr. 
3 az: 
60 min. 
16 oz. 
507% 
21.75 on, 
87 gr. 
16 oz. 
524 er. 
262 gr. 
Add the acid to the water, then the ammonia and finally B 
with constant stirring. 
