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  1. #31
    Photo Engineer's Avatar
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    Oh, the Ammonia is the bad actor if you use Ammonium Hypo. It effectively increases the activity of the halide solvent. It also increases the chance of fog and especially dichroic fog.

    PE

  2. #32
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    Quote Originally Posted by Photo Engineer View Post
    Do not use Ammonium Thiosulfate.

    There are many solutions to this problem, but some silver halide solvent is going to be needed.

    PE
    Good advice, stick to Sodium Thiosulfate

    “The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”

    Francis Bacon

  3. #33

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    Sodium thiosulfate was used in some early (1920 era) reversal processes, but it was somewhat tricky and often lend to fog. It is a silver solvent, needed in the first developer to produce a clear image. Sodium (or potassium) thiocyanate was found to be a better and more reliable solvent for this use. As noted above, ammonium compounds are generally bad actors in developers.

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