Bob Carnie
Allowing Ads
That's fine Bob.
Using Farmers reducer as opposed to a ferricyanide/bromide bleach is quite different in the way the bleach acts Dan. The Ferri/Bromide bleach works on the highlights first, while Farmers reducer works on the shadows as well.
Ian
wouldn't that produce the same effect as using Farmer's Reducer? If I understand it correctly, Farmer's has bleach and fixer so that the bleached image cannot be redeveloped?
Dan
That's correct. Farmer's Reducer is nothing but potassium ferricyanide (bleach) plus fixer. Using them together or sequentially has the same effect.
However, the mixture has the benefit that one can immediately see the bleaching progress. Unfortunately, it is not very stable due to a chemical reaction between ferri and fixer, causing it to lose its entire strength within 10-15 minutes.
Ian
What is a ferricyanide/bromide bleach?
A Potassium Ferricyanide/Potassium Bromide bleach is a re halogenating bleach, more usually used for toners.
For artwork and complex reduction it's sometimes more useful than Farmers.
Using Potassium Ferricyanide on it's own followed by fixing is quite different in effect to the action of Farmers Reducer.
If you add ferricyanide to commercial fixer it's an agressive bleach particulary if the fixer is ammonium thiosulphate based. However Farmers Reducer uses plain Sodium Thiosulphate and the action is far more gentle and it's useful for lightening shadow details and much slower working.
Ian
... Using Potassium Ferricyanide on it's own followed by fixing is quite different in effect to the action of Farmers Reducer. ...
I have not experienced any difference, and I don't see why this would be either.
Barry Thornton's Edge of Darkness describes a process whereby you selenium tone first, then wash, then apply the Potassium Ferricyanice/Potassium Bromide bleach (and 3g/liter is still kind of strong, in my experience); then fix again, but you can redevelop and do it all over again as long as you wait to re-fix until you're satisfied. The selenium holds back the darker areas, and the highlights get a fuller bleaching.
As other have noted, you get some changes in color (more with some papers than others); and every re-bleach, re-fix, re-develop or re-whatever that you do seems to take its toll on the print, until after several rounds you end up with something that just looks really...tired.
Bob, it's not an easy task to bleach and refix, then do any toning. If you bleach to completion and refix, everything is gone and there's nothing to tone.
... Perhaps a simpler explanation is that Ferricyanide on it's own attacks the smaller grains first, that's why it's used with or without bromide for split toning, but with Thiosulphate added Farmers Reducers attacks the larger "black" grains as well at the same time. ...
Ian : this sounds pretty logical, what do you think. If I bleach and refix after selenium, then move to my sepia tone and gold for the look, ??
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?