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by Ed Buffaloe
Salted paper is perhaps the most basic of the historical or alternative processes, giving a color much like Vandyke Brown but with no worries about residual iron compounds, and a longer tonal scale. The process combines a
salt and silver nitrate to form silver halide (usually silver chloride), but since silver halides are insoluble in water it is necessary to make them form within the paper itself by coating first with the salt solution and then
with the silver sensitizer. The paper is dried between steps.
Sizing paper with gelatin, arrowroot, starch, albumen, or even casein is recommended to keep the salt and silver solution from sinking beneath the surface--which causes the print to lose contrast. Often the size is
combined with the salt, but sometimes the paper is sized first and then salted. The Albumen and Salted Paper Book, by
James M. Reilly, states that typically the silver nitrate solution should be about 4 times as strong as the salt solution--so, if a 3% salt solution is used, a 12% silver nitrate solution is required.
Paper may be coated by immersion in the solutions, or by brush. Since the salt is relatively cheap, I find it easy to size and salt paper by immersion (which helps prevent
paper curling), but I generally use a brush or rod for coating the sensitizer. If you coat the salt solution by
brush, be sure to use a separate brush for salt and sensitizer. Do not use a brush with a metal ferrule. If you use a rod, a drop or two of 5% Tween-20 will help produce a more even coat with some papers.
Salted paper is particularly sensitive to minute impurities at every step of the process, so it is necessary to use
clean utensils and carefully guard against contaminating solutions. I have found it necessary to wash the print
in distilled water for two minutes immediately after exposure and before placing it in the wash tray for further
washing--it seems to prevent indiscriminate staining. Likewise, I find it necessary to replace the brush used for the silver nitrate solution fairly regularly.
Paper can be problematic--some papers seem to stain more than others. I have found Fabriano Uno to be a
good paper for the salt process, though I’m sure there are many others. I had many difficulties with Arches, but a friend achieved good results with a different batch of the same paper.
Toning is usually accomplished before fixing, but may also be done afterward. Gold is the traditional toner, but I find I prefer the color produced by a highly dilute solution of Kodak Rapid Selenium Toner (3 ml in 1
liter of water), used after the fix for 1 minute only--it produces a rich, chocolate brown color.
Salted paper is usually fixed in a 10% solution of hypo (100 grams of sodium thiosulfate in 1 liter of water) for 10 minutes. Two fixes are recommended for optimal print permanence.
Salted paper requires a very high-contrast negative with a density in excess of 2.0. I have a negative with a maximum density of 3.3 that prints quite well on salted paper.
Typical procedure:
1. Coat paper with salt solution (usually with size added), and dry.
2. Coat paper with silver solution, and dry thoroughly in the dark.
3. Expose paper by contact printing with a negative under UV or sunlight.
4. Wash in running water for 2 minutes. (I use distilled water with 2 minutes continuous agitation, followed
by a running water wash.)
5. Tone, as desired.
6. Fix for 10 minutes.
7. Wash for at least 40 minutes. The wash may be accelerated by the use of a wash aid such as Kodak
Hypo Clearing Agent or a 20% solution of sodium sulfite.
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