100 parts Alcohol, 95 deg 90 parts pyroxyline 7 parts B. White zinc in very 9 parts fine powder Castor oil 3 parts Alcohol 10 parts Grind in a mortar, adding ultramarine blue and carmine, or a little of any suitable coloring matters, and mix to A. When the collodion is dry, which requires a few hours, strip the whole or back with strong white or colored paper before stripping.
"Photographic Reproduction Processes"
P.C. Duchochois