Bruce Barnbaum - The Art of Photography - An Approach to Personal Expression

Potassium ferricyanide is a crystalline substance that can be purchased in one pound bottles. (A bottle of this size should be enough to last for many years.) A tiny amount of the orange crystals—perhaps a quarter of a teaspoon—is dissolved in water for subsequent application as a bleaching agent. I pour the crystals into a small glass container, add about two ounces of water, and stir until all the crystals are fully dissolved. The amounts of crystals and water are not terribly important—except that the more dilute the solution is, the slower it will work, and the more concentrated, the faster. I vary the concentration to suit my working procedures. I simply dissolve the crystals until the solution assumes a yellow color—not too deep a yellow. If the bleaching solution is too strong, it works too fast for me to control. That’s critical to remember, for my experience tells me that most people who have difficulty bleaching tend to mix too strong a solution.

When the print is on the vertical sheet of acrylic plastic and fully rinsed, I dip a paintbrush into the ferricyanide solution and proceed to “paint” areas of the print that I want to lighten in tone. I do this while the sheet of water from the hose rinse is running down the surface of the print to help even out the bleaching and prevent streaks. I direct a constant stream of running water onto the print just below the area I’m reducing to keep the bleach from running down and affecting other areas. When the bleach hits the stream of running water, it’s immediately diluted to such a high degree that it can’t bleach areas that are farther down the print. I work on one small area at a time in order to avoid streaks. Of course, I can orient the print on the vertical plastic in any direction (upside down, sideways, etc.) to avoid even the smallest amount of unintended bleaching. I “paint” for only a few seconds at a time before aiming the hose at the bleached area to rinse it thoroughly. Then I resubmerge the print in the fix.

As stated above, the fixer acts as a catalyst for the potassium ferricyanide, speeding up the bleaching action while at the same time neutralizing the bleach. By thoroughly rinsing those areas of the print where bleach has been applied before resubmerging the print in the fix, I can mute the catalyzing action. Using this procedure, only the bleach embedded in the emulsion will be catalyzed by the fix. If I fail to rinse the bleached area prior to resubmersion, the catalyzing action may be so strong that it bleaches away all existing tonalities.

Note

If the bleaching solution is too strong, it will work too fast to control. That’s critical to remember, for most people who have difficulty bleaching tend to mix too strong a solution .

After 15 or 20 seconds in the fix, all further bleaching action is completed—unless the bleach is so concentrated that a yellow stain is still visible, in which case bleaching will continue. I then remove the print from the fix, place it on the plastic sheet, and inspect it for results. If additional bleaching is desired, I repeat the process as many times as necessary to reach the desired tones. There is a limit, however, to the amount of bleach that can be applied—and the degree of lightening the print will accept—from numerous repetitions. If overdone, the print will stain yellow and the stain cannot be removed. The limits of bleaching vary from paper to paper.

Always remember to follow these important steps:

Prior to applying bleach, rinse the print

Apply the bleach

Quickly rinse the bleached area again

Resubmerge the print in the fix

Then inspect it to see how far the bleaching has gone

Note

Reducing (bleaching) does not produce the same effect as dodging!

If you watch the bleaching take place until densities are reduced to the desired level, then rinse and resubmerge the print in the fix, it will almost certainly go too far! Again, don’t mix too strong a solution, for it can become uncontrollable if it isn’t adequately diluted.

Some papers contain an additive that resists potassium ferricyanide reducer. (The additive also makes these papers resist selenium toning; see below.) If you use a paper that fails to respond to the bleach as outlined above, try using a more concentrated bleach solution, and do not rinse off the fix prior to applying the potassium ferricyanide. This usually overcomes the resistance. However, it’s quite difficult to accomplish subtle amounts of bleaching with such papers. It’s like trying to push a door that’s stuck—nothing happens as you push harder until it finally gives way and you go flying through! Ilford Multigrade IV notably resists bleach and toner. Surprisingly, Ilford’s Multigrade Warmtone responds well to both bleach and toner, though the same manufacturer produces both papers.

Reducing can be used under many circumstances. If an area of a print is too dark, the bleaching procedure can lighten it and even bring out unseen details in black areas. If an area of a print is too small or intricately shaped for successful dodging during exposure, the ferricyanide treatment can do the job after the print is developed. Note that brushes of any size can be used, from tiny ones for bleaching minute areas to large ones for lightening broad areas at once. When tiny, intricate areas require bleaching, it is best to squeegee the water from the print’s surface, paint the bleach on the precise area that needs reducing, then rinse and proceed as usual.

Reducing can also be used to lighten small areas throughout a print, enhancing highlights or opening up shadow detail. This is especially useful in cases when going to a higher contrast paper would make the overall print too harsh, or when a lower contrast paper would make the overall print too flat.

Potassium ferricyanide reducing increases contrast; dodging does not. Reducing removes silver equally from all areas bleached, whereas dodging lightens all areas proportionately . Let’s look at what this means. Suppose an area of a print contains a range of tones from light gray (say, 30 units of exposure under the enlarger) to medium gray (say, 200 units). If the area is dodged for one third of the exposure time, the light gray area would drop to 20 units, and the dark gray would drop to 133 units. Both tones would be lighter, but the relative contrast between them would remain about the same. However, if the same area is reduced with 20 units of light (or silver) taken away, the light portion would drop to 10 units, which is the threshold of print tonality, and the dark area would drop to 180 units, or only a slight change. Contrast between the two tones would be greatly increased by ferricyanide bleaching.

Contrast increase can be a double-edged sword—beneficial in some cases and detrimental in others. Many times I have tried to salvage an image that was printed too dark, only to find that as the overall tonalities started looking good, the highlights disappeared! On the other hand, if I have a print that needs a local contrast increase, I can print it slightly too dark in that area, then bleach it back, gaining additional contrast via the procedure. To bleach areas that are rather light in tone, I dilute the bleach far more than usual to slow its action and give me greater control.

Potassium ferricyanide reducing is deceptively difficult. I have ruined many prints—particularly through excess bleaching in the highlights. It’s a fabulous tool when necessary, but I advise you to use it only when absolutely necessary . I use it only if I must.