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Thread: Why acid fix?

  1. #31

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    Quote Originally Posted by dnmilikan
    The net result of this chemical reaction is lengthening the effective life of the fixer solution. This chemical reaction will continue so long as there is either the Sodium Sulfite or the Sodium Bisulfite present in solution for the free sulphur to recombine with.
    So the Sulfite has no real benefit for the fixing process itself? I am about to exclude the Sulfite and use a fixer consiting of Thiosulfite only as a one-shot (one-session) fixer for paper.
    Henning Jansen
    Stavanger - Norway

  2. #32
    Jorge Oliveira's Avatar
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    Bill Troop, co-autor of the development cookbook (or similar tiltle) and TF-2, TF-4 fixers posted a long thread in rec.darkroom news group of why alkali fixers.
    In short, he says (but many did not agree) it washes better.
    Usually they are not hardening fixers (but it could be done).

    Since they do not smell, I decided to use it for paper.
    For films, I use an acid hardening fast fixer.

    Jorge O

  3. #33
    Ole
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    I now use mostly TF2 for paper. For film, since I tend to use staining developers - and wish to preserve the stain - I mix a little Ammonium Chloride in plain hypo. So it can't be stored overnight? So what? I mix only as much as I need for one round of processing, and buy my hypo in 25kg sacks. I see no reason to skimp on the fixer, nor for worrying about exhaustion...
    -- Ole Tjugen, Luddite Elitist
    Norway

  4. #34
    Jorge Oliveira's Avatar
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    Ole

    This information re ammonium chloride fixers not suitable to storage is new for me.
    It doesn't keeps or what?

    Jorge O

  5. #35

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    Quote Originally Posted by jansenh

    So the Sulfite has no real benefit for the fixing process itself? I am about to exclude the Sulfite and use a fixer consiting of Thiosulfite only as a one-shot (one-session) fixer for paper.
    Some place in one of the Adams books [The print??] he mentions plain hypo for the second bath in a two bath setup. All the sulfite does is let you keep the stuff.

  6. #36

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    Quote Originally Posted by Jorge Oliveira
    Ole

    This information re ammonium chloride fixers not suitable to storage is new for me.
    It doesn't keeps or what?

    Jorge O
    I don't think he meant that. The lack of a perservite in the fixer is the problem.

  7. #37
    Jorge Oliveira's Avatar
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    Thanks, Robert

    Jorge O

  8. #38
    Ole
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    Quote Originally Posted by Robert
    I don't think he meant that. The lack of a perservite in the fixer is the problem.
    I must have made myself even less clear than usual

    You're right, Robert.

    Since Sulfite, as well as acidity, reduces the stain from pyro/pyrocat developers, it seems like a good idea to me to reduce their (fixer additives, not staining developers) use.

    This whole thread started with my discovering a recommendation to use acidic fix (sodium bisulfite) to remove the ugly stain on negatives developed in some developers, notably pyrogallol.

    It looks as if we now mostly agree that this might well be the case?
    So: Since I want to preserve the stain, I will drop both acidity and sulfite.

    Since one of the primary reasons for using a stop bath is to preserve the acidity of the fixer, that goes out the window too. Unless I need to stop development immediately, of course. Which I mosty don't...
    -- Ole Tjugen, Luddite Elitist
    Norway

  9. #39
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