"Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
"Nicholas O. Lindan" <nolindan@xxxxxxxxxxxxx> > The idea that faded prints are not recoverable has always > annoyed me.There is a chemical method which was published in one of the Kodak books ... I will cudgel my brain
No need to cudgel... Google knows all. Reproduced below.I confess I didn't use the method. Formaldehyde, Potassium Permanganate, and Conc. Sulfuric Acid aren't in my chemicals cupboard.
I decided a few hours of PhotoShop would be a better idea.The result looked good, but large liberties were taken in the restoration. At ~3 hours / restoration
you can't do very many in PS, and it certainly isn't cost effective. Somewhere there must be a 50 cents/50 seconds method. A modified scanner ... The postings on badly washed prints fading brought the matter to mind. ============================================================= 03:00 22 March 2000, Richard Knoppow wrote: The image may not be recoverable. Over time the silver has been turned into silver sulfide and silver oxide. The sulfide migrates in the emulsion staining the highlights. The prints should be copied using a deep yellow filter (#11 or G) to make copy negatives. Kodak published the following procedure for restoring faded prints on _developing out_ paper. Do NOT use this on toned prints on POP, it will destroy the image. 1. Clean the print thoroughly with film cleaner or some other non-water-based cleaner. 2. Fix the print in a plain hypo bath. Wash the print thoroughly. (These instructions pre-date hypo clearing agent. I think a treatment with it would be beneficial before the washing step here). 3. If the highlights are stained treat in a solution of the folowing: Kodak Rapid Liquid Fixer with Hardener. Dilute at film strength. To the diluted fixing bath add: Citric Acid, 28 grams per liter. Treat only one print at a time and watch it closely. Stop treatment as soon as the stain has cleared. If the solution attacks the image stop it immediately. Wash the print thoroughly after treatment. Again, these instructions pre-date KHCA and it is likely beneficial here. 4. Bleach and redevelop the print as follows: A. Treat with Kodak Special Hardener SH-1. This is a Formaldehyde hardener. Formaldehyde is toxic and a carcinogen. Its possible the process will work without it but the bleach is very swelling and may damage the emulsion without the extreme hardening of this solution. Treat in the hardener for five minutes and wash the print. B. Bleach in Kodak S-6 Stain Remover. and wash. Do NOT use KHCA after the bleach, the sulfite will partially dissolve the halide. C. Expose the bleached print to strong light. D. Redevelop in Kodak Dektol 1:2 or similar low sulfite active developer. D.Wash thoroughly. A plain hypo bath is: Sodium Thiosulfate, crystaline 240.0 grams Water 1.0 liter If anhydrous thiosulfate is used the amount is 160 grams/liter Crystaline thiosulfate is very endothermic so needs to mixed in hot water (125F). Anhydrous thiosulfate should be mixed in water not over 90F. Kodak Special Hardener SH-1 Water 500.0 ml Formaldehyde, about 37% solution by weight 10.0 ml Sodium Carbonate, monohydrated 6.0 grams Water to make 1.0 liter Note cautions above re. Formaldehyde Kodak Stain Remover S-6 Stock Solution A Potassium Permanganate 5.0 grams Water to make 1.0 liter Stock Solution B Cold water 500.0 ml Sodium Chloride (don't use table salt) 75.0 grams Sulfuric Acid , concentrated 16.0 ml Water to make 1.0 liter (Note: Most table salt contains iodine and other impurities, the iodine can cause staining) For Use, Take equal parts of A and B. The solutions do not keep in combination, mix it just before use. Bleaching should be complete in 3 or 4 minutes at 68F. The brown maganese dioxide stain formed by the bleach can be removed by treating in a 1% Sodium Bi-sulfite solution. Wash prints after bleaching. The print should be exposed to strong light, preferably daylight, before redeveloping.'Re-develop in Kodak D-72 or Dektol diluted 1:2.
== Nicholas O. Lindan Cleveland Engineering Design, LLC Cleveland, Ohio 44121 ============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.