Aggie is right on here. It takes a REALLY strong concentrated acid to cause potassium ferricyanide to release any cyanide gas. The chemical bonds of the iron and cyanide are very strong. Diluted stop bath won't do it. Acidic fixer won't do it. The book you mentioned by Susan Shaw is generally regarded by anyone with any chemistry knowledge as an alarmist, scientifically dubious cut and paste job that makes some wild extrapolations from a pile of MSDS information. Hysteria sells well in the USA.
Originally Posted by happysnapper
The short answer, yes, be careful with any chemical. Don't dip your hands in any solution ungloved. Wear a mask when mixing up dry chemicals. Ventilate your darkroom. Don't eat and drink in the darkroom. But you can relax about the potassium ferricyanide. (potassium cyanide is another matter altogether) Heck, that is the main ingredient in cyanotypes, which is considered safe enough for kindergartners to slop around and make sun prints.
Last edited by Sean; 07-22-2004 at 04:35 PM. Click to view previous post history.