A concern is the inadvertent mixing of bleach or acids into an aqueous ammonia tank. Such an event could potentially occur during delivery and unloading of materials. The reaction of ammonia and bleach could result in the formation of nitrogen trichloride that is explosive. Mixing of ammonia ...
It is also possible to bleach out the silver and print by the stain alone. Once widely used, pyro formulas fell out of vogue due to the difficulty of controlling the staining effect. However, the Wimberley WD2D formula and Gordon Hutchings' PMK (pyro-metol-kodalk) formula both give ...