MISCEELANEOUS PRINTING PROCESSES) 321 
tiveness of complex organic compounds, which under the 
action of light form coloured dye images. Feer suggested the 
following: 
A. Sodium toluoldisazosulphonate 25 ¢ LOZ er 
Beta-naphthol 25\¢ 192 gr. 
Caustic soda 8g 61 gr. 
Water 1000 ccm 16 oz. 
Gives scarlet red images. 
B. Sodium ditolyltetrazosulphonate 25 g 192 ger. 
Metaphenylendiamine 20 g 154 gr. 
Water 1000 ccm 16 oz. 
Gives brown images. 
C. Sodium ditolyltetrazosulphonate 25 g 192 gr. 
Resorcine 22g 169 gr. 
Caustic soda l6g Woes ae. 
Water 1000 ccm 16 oz. 
Gives orange images. 
D. Sodium ditolyltetrazosulphonate 30 g 230 gr. 
Resorcine 20 g 154 er. 
Caustic soda l5¢g LEDS) ong 
Water 1000 ccm 16 oz. 
KE. Sodium ditolyltetrazosulphonate 30 g 8)0) (ain 
Alpha-naphthol 25). 192 gr. 
Caustic soda 7g 54 gr. 
Water 1000 ccm 16 oz. 
F. Sodium ditolyltetrazosulphonate 30 ¢ 230 ger. 
Paraphenylendiamine 20 g 154 er. 
Water 1000 ccm 16 oz. 
A, B, C can be used alone; D and E mixed in equal volumes 
for violet tones; or E and F in equal volumes for blue tones. 
After exposure, which is about 5 minutes in sunlight, the 
prints should be washed in water acidulated with hydro- 
chloric acid. 
