By Jean-David Beyer for the Large Format Page
You should look into Ansel Adams' book, "Polaroid Land Photography", New York Graphic Society, 1963, if you can get a copy. I assume it is still in print. Good libraries will have it, or get it on inter-library loan.
1.) Polaroid recommends clearing the film with a bath composed of 180 grams sodium sulfite in 1 litre of water. 2.) If you then wish to harden them, a bath containing, in 1 litre 28% acetic acid 250 ml Potassium alum 16 gram 3.) Don Leavitt, in Popular Photography, November 1966 recommended combining the results of 1 and 2 (not the solutions themselves) by using in 1 litre Potassium alum 30 gram sodium bislufite 60 gram water to 1 litre Note that this solution gives off an irritating gas; probably sulfur dioxide. I keep it in a glass bottle with a metal screw-on cap. It ultimately dissolves the metal cap, but not in a day or two. Plastic containers, provided they do not leak, would probably be better than what I use in many ways. The advantage of this solution is that "the negatives may be stacked together in a small container, without dividers, since the negatives harden as they clear and thus are less susceptible to scratching." 4.)Ansel considered this (normal processing) "quite permanent". However, 5.) "Whenever archival treatment is desired, use the following procedure after compliting the sulfite clearing and acid-hardening process: 1.) Rinse negatives. 2.) Fix in a standard fixing bath (F-5 or F-6) for 3-4 minutes. Do not use rapid fixers. 3.) Rinse. 4.) Treat for 2-3 minutes in a hypo-clearing bath to which a small amount of Kodak slelenium toner has been added (about 1:20). 5.) Rinse. 6.) Wash thuroughly. 7.) Immerse in fresh solution of wetting agent solution (Kodak Photo-Flo, for example) for a minute or so. 8.) Hang up to dry in a clean area. 9.) When thuroughly dry, store in chemically safe envelopes in a cool, dry area." 6.) Most users find that using an EI of 20-25 for 55 will give the best negatives, whereas an EI of 64 is best for the print. This may vary some from batch-to-batch, but not much.