MISCELLANEOUS PRINTING PROCESSES 323 
Andresen suggested the following process: 
Benzidine Zoe 177 Se. 
Water 1000 ccm 16 oz. 
Boil until dissolved, and add: 
Sulphuric acid 37:5, ecm 288 min. 
Water 3/.5.cem 288 min. 
Allow the mixture to cool; then with the aid of ice reduce 
the temperature to 5° to 10° C. (41° to 50° F.), and a copious 
precipitate should be formed. Add slowly: 
Sodium nitrite (not nitrate) 18¢ 138 gr. 
Water 50 ccm 34, OZ. 
Stir until a clear solution is obtained, and pour into: 
Alcohol 5000 ccm 80 oz. 
The diazobenzidine will be precipitated. Filter and wash 
with alcohol two or three times, and dissolve in: 
Water 1000 ccm 16 oz. 
During solution the water must be kept cooled down to 5° C. 
(41° F.). This precipitate must not be allowed to dry, as it 
is very explosive. Keep the solution cool, and float paper 
on the surface, or immerse fabrics completely. Dry in the 
dark, and expose under a positive. The developer may be a 
2 per cent solution of amido-naphthol-sulphonic acid-5 or 
the corresponding -9 compound with 2 per cent caustic soda. 
Andresen also patented the following process: 
Water 150 ccm D/Oz: 
Heat in a porcelain dish to boiling, and add: 
Beta-naphthylamine 14.3 ¢g 220 er. 
Add slowly: 
Hydrochloric acid, sp. gr.1.19 10ccm 152 min. 
Stir until dissolved, and add with constant stirring: 
Hydrochloric acid 40 ccm 617 min. 
Cool the thick paste with ice to 5° C. (41° F.), preferably by 
adding the ice to the liquid, and add with constant stirring: 
