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Thread: TF-4 fix

  1. #41
    Donald Qualls's Avatar
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    OTOH, phenolphthalein may be a "regulated substance" these days, since they pulled it from the laxative market after finding out it was carcinogenic (if you used it, as a laxative, every day for about twenty years, I think). And again, it's still one more chemical to source; I'm reasonably sure I won't be able to get it from the local pharmacy, and if I were interested in buying the chemicals from a chemical dealer, I'd just get ammonium chloride and be done with it, or buy TF-4 from Formulary.

    Red cabbage juice is litmus -- that is, litmus indicator is made from red cabbage. As suggested, though, while it's nice for getting a quick and dirty indication of "acid or base" the change is too gradual to use for an end point. And of course the indicator in stop bath changes color at a distinctly acidic pH (about 5.8, IIRC), which is inconvenient if you want to be slightly alkaline. I suppose I could get a pH test kit at the same pool/spa outlet that will presumably supply the hypo crystals, but then I'm paying for someone to package it up so a pool owner who knows nothing at all about chemistry can keep his pool comfortable.

    Part of the point, for me, is establishing the ability to keep this stuff up after the analog photo industry as we know it is gone -- but then if I'm making modern Daguerreotypes on silvered glass, and developing them in vitamin C and coffee (to avoid the mercury), I can fix them just fine in plain hypo (as was done 165 year ago). The other part of the point was to try to figure a simple way to do things with chemicals that aren't labeled as photographic, and automatically marked up 400% as a result...

  2. #42

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    Plain Sodium Thiosufate (Hypo) and Ammonium Chloride are readily available as bulk dry chemicals and they are inexpensive. Ammonium Sulphate is also readily available as a bulk dry chemical and it is inexpensive. The combination of Hypo and either Ammonium Chloride or Ammonium Sulfate will give you a near neutral pH Ammonium Thiosulfate fixer (non-hardening).

    If you want to buffer your Ammonium Thiosufate fixer, there are several inexpensive chemicals available including Sodium (or Potassium) Metabisulfite and Sodium Sulfite.
    Tom Hoskinson
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    Everything is analog - even digital :D

  3. #43
    MikeS's Avatar
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    I use Kodak C41 and I add 1oz. of Ammonia (regular household stuff) per liter which brings it up to a pH of 7 when I'm developing with pyro or another staining developer. When I'm using non-staining developers I also use C41 fixer, but instead of the ammonia I add about 10ml of hardener in it . This works fine for me.

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