Final Processing Sensitometry

Figure 6-1. Half Dome. Clouds, Winter, Yosemite Valley, California. The problem here is to differentiate between the whites of the sunlit snow and the cloud. The sky area was burned about 15 percent, and both edges received about 10 percent burning. The level snow on the valley floor was of about the same values as the snow in the trees. I burned the level snow area by moving a card with a small hole constantly across the image for about 20 percent of the total exposure. 1 used the hole rather than the edge of a card because I wanted to "explore" this area, avoiding over-burning of the tree trunks. Without this burning the snow value was quite unpleasant. The trees on the left were in the beginnings of an encroaching cloud shadow, and were in full shadow a short time after exposure.

I was using a 4 x 5 Area Swiss camera with 121mm Schneider Super An-gulon lens and a Wratten No. 12 filter. The film was Kodak Tri-X and I gave Normal-minus development in HC-110. The print was made on Ilford llfobrom Grade 2 developed in Dektol.

Careful fixing and final processing are extremely important if prints are expected to last more than a few years or decades. For test prints and work prints that are to be saved only for short-term reference, a somewhat abbreviated fixing and washing procedure is adequate. However, fine prints should be processed fully and toned, and all file proofs and work prints will require full two-bath fixing and washing. Many documentary and news photographs are also worthy of archival preservation; such photography is visual history, and should be respected. Thus the specifics of the final processing may vary somewhat depending on the intended use of the prints.

The use of two separate fixing baths is very important, and should be considered standard practice for all prints. The two-bath process is necessary because some of the by-products of fixing are contaminants that form in the hypo solution as it is used. These substances are extremely difficult to wash out of the paper fibers; the fresh second fixer helps prevent their formation and removes any that are present. The prints must be agitated and separated constantly throughout the fixing process. However, you must avoid over-fixing, since the fixer itself will begin to bleach out the image silver, especially if a rapid fixer is used. In addition, prolonged fixing allows the hypo and residual contaminants to permeate the paper fibers thoroughly, and they become even more difficult to remove. Use fresh fixing solutions and observe the time closely.

FIXING AND WASHING UNTONED PRINTS

For prints that are not to be toned, I recommend an acid-hardening fixer for both solutions — a 3-minute treatment in the first fixer followed by 3 minutes in the second. A plain hypo bath is sometimes used for the second fixer, but in that case the wash water must be relatively cool — about 65°F — to avoid possible detachment of the emulsion along the print edges. During the work session, prints can be stored in cold water after the first fixing and a thorough rinse. They are then given the second treatment in fixer at the end of the session. Since the second fixer does relatively little "work" and contains few contaminants, it is possible to save it and use it as the first fixer in the next printing session; however, I now use fresh fixer for both baths.

When taken out of the second fixer, the prints should be rinsed on both sides under running water to remove surface chemicals, and then placed in a deep tray or sink for further rinsing. An initial 5- to 10-minute rinsing through several changes of water is very important to remove the bulk of the fixer and residual contaminants. A strong stream of water is not required for adequate rinsing, but it is important that all prints be separated and that fresh water be supplied at an adequate rate. The prints should then be treated for 3 minutes in Kodak Hypo Clearing Agent or the equivalent, mixed as see page 134 directed on the package, followed by a rinse and final washing. <

FIXING, WASHING, SELENIUM TONING

Prints that are to be toned should receive only the first 3-minute treatment in acid-hardening fixer. They can then be rinsed and stored in cold water until you are ready for the second fixer treatment just prior to toning, as discussed below.

A number of toning formulas are available, and many provide both a change of image color and a measure of protection of the finished print from harmful gases in the air. Sulfide toning has archival benefit, for example, but I do not favor the print colors it yields. The only toner I use or recommend is selenium, which produces a slight cooling of the image color and neutralizes the unpleasant greenish cast of many papers. As toning continues, the low values become deeper and richer and assume a degree of color, usually a cool purple-

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Figure 6-2. Rocks, Baker Beach.

|A) This is a slightly soft print on llford Gallcrie Grade 1.

|B) An identical print was treated in selenium toner. llford Gallerie is unique in having a strong tendency to intensify in selenium toner with almost no color change.

brown, depending on the paper type. The resulting slight contrast increase should be anticipated when making a print you expect to tone. Selenium toning is an important part of archival processing of prints, < and it is also an excellent intensifier for negatives.

I strongly advise using the pre-mixed toner; the mixing of selenium toner from basic ingredients can be dangerous in that inhaling the selenium powder is very harmful. With the prepared solutions (such as Kodak Rapid Selenium Toner), I am not aware of any danger (although ingesting the solution is certainly not advised!). I have used selenium toner for over forty years with no apparent ill effects. However, for those who have an allergic reaction to selenium, the use of rubber gloves or tongs will be necessary.

I must also caution about the image color effect of selenium toning. The color changes are often subtle, and the final visual effect depends partly on such details as the nature of the light used to evaluate the prints during toning, and the viewing light used for display. The subtle color changes of toning are more apparent under tungsten lighting than in daylight. In addition, the degree of development of the print will affect the toning action: prints that received shorter development time tend to take on a warmer and more obvious tone, and prolonged development of the print minimizes the color change. Sometimes prints will lose tone in the final washing and drying. All these effects may vary from one paper to another, and experimentation is required.

In previous years, when papers could be neatly classified as chloride, chloro-bromide, bromo-chloride, and bromide, the selenium toning effects could be predicted largely by paper type. It was generally agreed that the more silver chloride a paper contained, the more pronounced the effect of selenium toning; bromide papers

Figure 6-2. Rocks, Baker Beach.

|A) This is a slightly soft print on llford Gallcrie Grade 1.

|B) An identical print was treated in selenium toner. llford Gallerie is unique in having a strong tendency to intensify in selenium toner with almost no color change.

toned only slightly, if at all. My more recent personal experience indicates that papers such as Azo (presumably still a chloride paper] see pages 49-51 tone very well. Many other contemporary papers tone beautifully, <

but the effect must be determined by trial since we do not know the composition of their emulsions.

Continue reading here: Toning Procedure

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