The processing procedures outlined throughout this chapter constitute black-and-white archival print processing. They include two fixing baths for full removal of salts from the emulsion and paper base, selenium toning for greater resistance to environmentally induced damage, and complete washing of prints to remove all remaining acids and salts.
A quick review of my current steps toward black-and-white archival processing may be usefuclass="underline"
Use two fixing baths to remove all silver salts.
Fix prints for a total of seven minutes in the two standard fixers (see manufacturers’ recommendations for varying this time for some fixing baths).
After fixing, hose rinse each print and place in a tray of water with water trickling into it.
Accumulate all fixed prints in the holding tray of water.
Bathe all prints in a hypo-clearing agent bath (to prevent staining in selenium toner).
Accumulate all prints in a holding tray of water.
Selenium tone all prints. (Other toners may be used instead of selenium.)
Hose rinse each print and place in a tray of water with water trickling into it.
Place prints in the second, third, and fourth trays with water trickling into each.
Squeegee each print and place on a screen (emulsion side down) for drying.
Toning, Intensifying, and Reducing Negatives
Negatives, too, can be selenium toned to increase contrast, density, and permanence. Just as selenium combines with the silver in the paper’s emulsion, it combines with silver in the negative’s emulsion to increase density. This process does not increase grain, an unwanted effect of all other negative intensifiers. Also, all other negative intensifiers, such as chromium intensifier, theoretically degrade the permanence of the negative; selenium treatment enhances it! I use a strong 1:1 dilution of Rapid Selenium Toner with water to intensify negatives.
Selenium treatment of negatives is performed after the processing is completed, so it can be done days, weeks, or years later. A low contrast negative can be intensified, but it works to best effect if the negative has good density to begin with. A thin negative does not offer sufficient silver to combine chemically with the selenium. Just immerse the negative in a solution of selenium and agitate for 15–20 minutes for full effect. Re-wash the negative after treatment, immerse it briefly in Photo-Flo, and hang it to dry. If agitation time is shorter and the contrast increase is insufficient, repeat the process. However, there is an upper limit to the amount of selenium that can be bonded to the existing silver in the emulsion, and therefore an upper limit on the possible contrast increase.
The increase in contrast due to selenium toning of a negative may be the equivalent of an N+ development instead of N. This has particularly important consequences for roll film users, as it extends the use of the zone system to subsequent redevelopment of the negative. Selected frames can be cut out, increased in contrast with selenium, and enlarged more effectively afterwards. It also allows for rethinking negative development in situations where it’s difficult to decide on the appropriate level of contrast. You can always choose the lower contrast option, then later switch to the higher contrast approach via selenium treatment of the negative!
Potassium ferricyanide can reduce density in overly dense negatives. Interestingly, though reducing a print increases contrast to a great extent, reducing a negative (at least the Kodak Tri-X negatives I have subjected to potassium ferricyanide) seems to reduce contrast slightly. My procedure is to set up three trays: a fixer tray on the left, a water tray in the center (with a hose delivering fresh water to that tray throughout the process), and a potassium ferricyanide tray on the right. I first immerse the negative in the fixer tray for several minutes, then rinse it in the water tray, then fully immerse it in the potassium ferricyanide solution, rocking the tray gently. Make sure the negative is fully immersed in the bleach at all times, or an unwanted tonal break will appear wherever the negative is not immersed. Then I remove it from the bleach, rinse it in the water tray, and place it back in the fix. I do this as many times as necessary to bring the overly dense negative back to more reasonable, printable densities.
The key is knowing when to stop this procedure! Always maintain ample tonal density and separations in the shadow (thin) areas of the negative. If you continue the process for too long a time, you can lose those critical shadow areas, permanently destroying the negative. At first, the changes may seem painfully slow because the negative is so dense. After you get past the grossly dense stage, watch it carefully, for the same amount of bleaching will seem to yield far greater density changes that can easily get away from you.
Cold, Neutral, and Warm Tone Papers
Another aspect of black-and-white papers that was mentioned earlier but not discussed is the inherent coloration of the paper. “Cold tone”, “neutral tone”, and “warm tone” papers each have their adherents. Cold tone implies a blue/white base, neutral tone implies a relatively neutral white base, and warm tone implies a yellow/white base. Some photographers print on one type of paper to the complete exclusion of others. (I use neutral and cold tone papers; Jay Dusard uses only warm tone papers). Some people feel that warm tone papers impart a pleasant, “old” look to a print. Some people prefer to print on neutral or cold tone papers and then use a sepia, brown, or heavy selenium toner to obtain a brown image—one with a different coloration from the warm tone papers.
My observations show three major differences among the papers. Warm tone papers have a warmer, yellower base than all neutral or cold tone papers. Toning does not change the base color of papers, so a toned neutral or cold tone print will not have the same overall look as one printed on warm tone paper. Warm tone papers are much, much slower to expose under the enlarger than the neutral or cold tone papers. They may require two stops of extra exposure to obtain the print you would get on a neutral or cold tone paper. This can present difficulties if your negatives are small and your enlargements are great, and/or if your negatives are very dense. Finally, some warm tone papers tend to have less contrast variation than neutral or cold tone papers.
Review of Contrast Controls
Before moving on to traditional color printing, it will be helpful to review the numerous controls discussed throughout the book for increasing and decreasing contrast. I have often seen photographers avoid subjects in the field that they feel are either too high or low in contrast, and I hope this review may embolden some to rethink the artistic possibilities of such subjects. (Also see the following section on Infinite Contrast Control after Negative Development.)
In addition to the controls listed below, be aware of the fact that the light source on your enlarger affects the contrast of your print. For complete information on the differences between diffusion, condenser, and point source enlarger lights, see Appendix B.
How to Increase Contrast
Filtration during negative exposure. The appropriate filter can further darken a dark area in relation to a lighter area, or brighten a light area in relation to others.
Long exposures and reciprocity failure effects. If the light is dim enough, the film is already in the realm of reciprocity failure and therefore increased contrast. If the scene is bright, a strong neutral density filter—perhaps in combination with another filter—can extend exposure times into the realm of reciprocity failure.
Extended negative development.
Selenium toning of negatives.
High contrast grade of enlarging paper.