"Mark Lent" > I don't really know if this has been discussed, but if you're using > Potassiumferricyanide (sp?) for bleaching, make sure that you don't use it > near stop-bath. The chemicals in the stop-bath has an agent that releases > cyanide gas if it is mixed with PFC. decomposition of potassium ferricyanide takes place at *REALLY* high temperatures and not much else, though very low amounts can and do occur when people throw every darkrrom chemical together and bleach is included http://en.wikipedia.org/wiki/Potassium_ferricyanide potassium ferrOcyanide however is a different story and it's toxicity and similarity of name leads to confusion http://en.wikipedia.org/wiki/Potassium_ferrocyanide and in one instance I know of, a 'tech' bought the wrong stuff, and a terrible accident could have occured (!) but didn't when I spotted the chemicals they were about to mix (!) :) karl
