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Discussion in 'B&W: Film, Paper, Chemistry' started by Aggie, Feb 21, 2003.
I've done a little. The best articles I've read on it are Bruce Barnbaum's piece in _Mastering the Black and White Fine Print_ (_Photo Techniques_ special issue no. 11) on local bleaching, and Les McLean's description of general bleaching in his book.
I occasionally use local bleaching. If I want to get a little more luminosity in a highlight, I pull the print from the fixer, apply a potassium ferricyanide solution with a brush, applying and rinsing as Barnbaum describes, and when it's about right, put it back in the fixer to clear the bleach and bleached silver (it continues to bleach somewhat in the fixer), then wash and tone as usual.
It's not that mysterious once you've tried it. It helps to have an area that is well defined, because the bleach will work faster on light areas than dark areas, so orient the print so that you have a dark area below the area to be bleached to minimize drip marks. This fact also means that contrast will increase in the bleached area.
Ilford Galerie and MG (RC or FB) seem not to bleach well in my experience. Oriental Seagull, Cachet Expo, and other papers take to it more readily.
Les's process involves bleaching the whole print, which will increase overall contrast and push up all the highlights in general.
Also, potassium ferricyanide is probably the most poisonous thing we use in the darkroom, so be careful, don't point brushes on your tongue (one of those things painters do that never really made sense to me), keep out of reach of children, label bottles clearly, etc.
I would agree with David's description with the addition that there are several bleaching formulas that are available for use. One that I know of is an Iodine formula and it is used by some printers with excellent results. The only difficulty that I have heard is that since it is iodine it is more difficult to determine the degree of bleaching obtained.
Of course one can buy premixed Farmers Reducer and it seems to work. Additionaly I have come across this formula from Lynn Radeka and I will post it below since it gives somewhat greater flexibility then Farmers in that it is faster acting if needed, but also can be diluted if more time is desired for control of it's action.
My initial reaction was that it was somehow less "pure" then the purely technical way of proper exposure, correct burning and dodging etc. I have seen the results that some really fine printers obtain and there is no denying the possibilities that it affords. However, the effects are not reversible. Now for the other recipe.
Solution A 500 gm Sodium Thiosulfate to 1 litre of water
Sorry about that, posted before I was finished.
Solution B 5 gm Sodium Hydroxide to 100 cc water
Solution C 8.4 gm Potassium Fericyanide to 100 cc water
These three stock solutions should be stored separately in brown bottles before use and mixed in the following proportion 1 oz A to 1 cc of B to 4 cc of C. If a slower action is desired you may add 1 oz of water. This is a very fast acting formula that will work on upper midtones and highlights.
David's suggestion that you read Bruce Barnbaum's article is sound advice although I would suggest a modification to his method; don't wait until the bleaching is completed before you place the print in the fixer for you will run the risk of staining either immediately or within a few weeks of drying the print. I would suggest that you apply the bleach and rinse with water but every third time I rinse I place the print into the fixer to neutralise it in stages. When the bleaching is completed I fix the print for two minutes. When I first used bleach I rinsed with water as Bruce does but found that I did ocasionally experience staining but since I adopted the method I have suggested here I have never had a print go bad on me.
Another tip is to work with a weak solution and be patient. If you can see the bleach working as soon as you have applied it you will not stop the action and you will ruin the print. When I apply bleach I don't expect to see any change in the tonality for the first three or four applications.
This is something, for me, that is a "hit or miss" proposition. Make sure that you have a good source of running water near by when you start. This is for local bleaching only. You can swab on the bleach or use one of those Chinese watercolor brushes.
I like to print the highlights a little veiled (read a little to dark) and then put the whole print back in the bleach (Farmers Reducer) for a little time. IF you like the look of the print, in my experience, you are too late.
Good luck! Tip: the question is like asking someone for directions to Carnegy Hall. The answer is "Practice Practice Practice.
Les's suggestions are good ones. I tend to use bleach on highlights that don't need that much more pushing, so three or four applications of relatively weak potassium ferricyanide are just enough usually just to get that little extra sparkle after I've done other things like dodging and adjusting contrast. Barnbaum uses bleaching more heavily than I do, it seems. It's particularly handy if you like graded papers like Azo and Cachet/Maco Expo which only come in two or three grades, making all the old tricks a real necessity.
If I may add just a couple of things. Use a large piece of plexiglass standing up toward the back of your sink. Have the running water in a hose in one hand and the brush or a small cotton pad in the other. You want to keep water running on the print underneath the place where you are working, and also rinse it off frequently. Once you mix the bleach, is dissipates rapidly, probably within ten minutes, so only mix a small amount at a time. If you are going to try it, make several extra prints and be prepared to toss them as you learn. It can also be helpful in the shadows. Good luck. Tom Perkins
I'm reading Tim Rudman's book Master Printing Course that covers this area greatly and has 3 or 4 diff formulas for bleaching wet or dry prints. Very good info.