View Full Version : Making Photographic Bleach

brian steinberger
22-Dec-2006, 22:42
I have always made photographic bleach for reduction on prints by adding potassium farricyanide to water. I just got a copy of the darkroom cookbook which suggests adding potassium bromide along with the potassium ferri to a "solution A" and then a solution B including water and hypo.

Is all this necessary? And what is the purpose of adding these to solutions together? Can I continue to get away with a jar of potassium farricyanide and water?

Jim Noel
23-Dec-2006, 17:07
The info you read is not uncommon, in fact in the correctproportions this is Farmers Reducer.

If you are getting the results you desire, why even think about changing?

brian steinberger
23-Dec-2006, 17:43

I didn't know if I was supposed to use these other ingrediants. Why even include them?

Donald Qualls
26-Dec-2006, 16:04
The bromide is present to ensure conversion of image silver to a fixable halide form (instead of potentially leaving silver in a non-fixable complex of ferricyanide). The fixer (which is essentially what Solution B of Farmer's Reducer is) is to then remove the halogenated silver. If you fix separately after bleaching, you don't really need Solution B, though it can be tricky to judge bleaching progress without fixing as you go. I'd certainly recommend a halide source, but table salt works as well as potassium bromide in the rehaolgenating step, and you probably already have it on hand... ;)