Ammonium Thiocyanate
From George Eastman House : Notes On Photographs
Colorless deliquescent crystals made by boiling an aqueous solution of ammonium cyanide with sulfur or polysulfides. It must be kept in a well-sealed container. The principal use for ammonium thiocyanate was in gold-toning formulas, but it was also used in a 5 percent solution to dissolve gelatin in overexposed carbon prints.[1]
- ↑ Osterman, Mark. 2007. Ammonium Thiocynate, NH4CNS. In The Focal Encyclopedia of Photography: Digital Imaging, Theory and Applications, History, and Science, ed. Michael R. Peres, 41, Focal Press.