MISCELLANEOUS PRINTING PROCESSES 319 
Water 1000 ccm 
Or (Vogel) : 
Potassium bichromate oes 
Phosphoric acid, sp. gr. 1.124 500 ccm 
Water 500 cem 
Or (Weissenberger ) : 
Potassium bichromate 100 ¢ 
Sulphuric acid 133 cem 
Water | 1000 cem 
16 oz. 
38.5 gr. 
8 Oz. 
8 oz. 
770 gr. 
1020 min. 
16 oz. 
The sulphuric acid in this formula may be replaced by 
122 ccm (936 min.) phosphoric acid, sp. gr. 1.117. 
Or (Weissenberger) : 
Potassium bichromate 66.6 g 
Potassium bisulphate 300 g 
Manganese sulphate 26.6 
Water 1000 ccm 
Or (Weissenberger ) : 
Potassium bichromate 75g 
Sodium acid phosphate 200 g 
Magnesium chloride 75g 
Water 1000 ccm 
This last is said to be the best formula. 
Si2'er: 
2304 er. 
205 gr. 
16 oz. 
576 gr. 
1536 ger. 
576 gr. 
16 oz. 
Paper, which must be free from wood pulp, should be 
floated on one of the above for from 1 to 2 minutes and 
rapidly dried. Exposure in diffused light will vary from 10 
to 60 minutes, according to the thickness of the paper on 
which the drawing is made. In sunlight the exposure will 
be about one-third of the time. Development is best effected 
by laying the paper at the bottom of a box to the lid of which 
is pinned a sheet of stout blotting paper moistened or sprayed 
with: 
Commercial aniline 500 ccm 
Benzole 500 ccm 
8 oz. 
8 oz. 
