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  1. #21
    gainer's Avatar
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    Actually, I think you could use Iron Out, obtainable at most supermarkets in the cleanser department. It is sometimes described as a developing agent, but it has such a high fog level that if you leave film or paper in it long enough, it will go to completion. I don't see that the development is so messy. You could also use ascorbic acid or hydroquinone in a strong carbonate solution to blacken it, then wash and dry it, and you'll have a very black emulsion. The bleaching is also only a single soak, wash and dry operation. It won't take much time or money to find if it's worth doing more of.
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  2. #22

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    ok, so I run the exposed paper though a rehalogenating bleach, and that might reform the silver chloride/bromide [etc] so that it is no longer activated? will it still be on the paper, or aqueous in solution, needing to be applied to the paper.

    and if the paper is already exposed, why would I need to run it through Iron Off??

  3. #23

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    Actually, most water purification tablets contain iodine as the active ingredient.

  4. #24

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    Quote Originally Posted by pnance View Post
    Actually, most water purification tablets contain iodine as the active ingredient.
    How would I want to use that? what form of iodine is it? Where on the activity series is Iodine compared to silver?

  5. #25
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    Quote Originally Posted by knoxissimpler View Post
    ok, so I run the exposed paper though a rehalogenating bleach, and that might reform the silver chloride/bromide [etc] so that it is no longer activated? will it still be on the paper, or aqueous in solution, needing to be applied to the paper.

    and if the paper is already exposed, why would I need to run it through Iron Off??
    Exposed silver halide is not necessarilly silver. You need to reduce the exposed silver halide to silver. Iron Out is a reducing agent composed mostly of sodium thiothionite IIRC. It will blacken the silver halide by reducing it to metallic silver and a different halide compound. I'm sure there are many other chemicals that will reduce the silver halide. A developing agent is a reducing agent that responds preferentially to exposed silver halide. There are many of these as well. If you use one that is not preferential, you will not have to expose each sheet to light in order to be sure of reducing all the silver halide.

    Unless you use something like chlorine bleach that takes off the emulsion, most of the silver if not all will remain in the emulsion just as the silver image remains in the emulsion after noemal fixing.

    This solid black "image" is not active. The problem I see in going straight to the bleach while there are still original halides of silver remaining along with photolytic silver is that I suspect that the bleach will convert the photolytic silver to the bromide and/or chloride that you put into the bleaching solution while leaving the original silver halide, thereby causing uneven sensitivity, resulting in mottled images.
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  6. #26
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    Quote Originally Posted by knoxissimpler View Post
    How would I want to use that? what form of iodine is it? Where on the activity series is Iodine compared to silver?
    I didn't say one should use water purification tablets for anything but purifying water. In fact, I was trying to say that I thought the hypochlorite might be accidentally formed while trying somehow to use elemental chlorine to form the silver chloride, and that would be a bad thing, because it would damage if not destroy the gelatine emulsion. So, DO NOT use either form of water sterilization tablets in this process.
    Gadget Gainer

  7. #27
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    To sum up, my suggestion would be to develop your paper in a strong print developer with the room light on so that it turns as black as it will go. Wash it thoroughly, bleach it under red light in the ferricyanide + potassium bromide or chloride solution, wash and dry it (still in dark or safelight) and see if you can use it as contact printing paper.
    Gadget Gainer

  8. #28

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    Quote Originally Posted by gainer View Post
    To sum up, my suggestion would be to develop your paper in a strong print developer with the room light on so that it turns as black as it will go. Wash it thoroughly, bleach it under red light in the ferricyanide + potassium bromide or chloride solution, wash and dry it (still in dark or safelight) and see if you can use it as contact printing paper.
    what is the prupose of the ferricyanide? (FYI, I do not like to mess with cyanide, with a couple exceptions)

  9. #29
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    Wow, if youre going to do all this work, it must be for quite a pile of paper. How much paper did you fog?

  10. #30
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    Quote Originally Posted by knoxissimpler View Post
    what is the prupose of the ferricyanide? (FYI, I do not like to mess with cyanide, with a couple exceptions)
    Ferricyanide, usually the potassium compound, IS the bleaching agent most often used.

    FYI, ferricyanide is not cyanide. If you use Farmer's Reducer or the bleach-redevelop method of sulfide toning, you are probably using ferricyanide. It is used in many photographic processes. Perhaps one of the professional chemists in our group will explain the difference and the necessary precautions for unusual use. It is not the same as potassium or sodium cyanide, which will generate HCN gas even in mildly acidic solution.
    Gadget Gainer

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