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  1. #11
    Greg Davis's Avatar
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    Ed, I don't regenerate simply because Kodak specifically recommends against it when using a rotary processor in the Z-131. I admit, though, that I haven't tested it one way or the other with my process control strips to see if there are any consequences of regenerating. But since it only costs me 19¢ per 8x10 sheet in bleach, I haven't worried about it much.
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  2. #12
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    A rotary processor aerates the bleach and thus regenerates it as far as oxidation is concerned.

    However, a bleach is used up by consuming halide ions and therefore oxidative regeneration is not, in itself, sufficient to restore the bleach to its original activity. Then there is the pH change to consider and other minor changes.

    You cannot do this for too long of a time before you run into problems with retained silver, higher grain and reduced color saturation.

    PE

  3. #13

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    PE, thanks for the details! I wish there was an easy way to tell when bleach was no longer regenerateable. I use the kodak bleach regenerator product to regenerate it, which seems to have worked fine so far. I should run a test with fresh bleach to see if I can detect a difference.

    Ed

  4. #14
    Greg Davis's Avatar
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    Would a test like Kodak ST-1 work for residual silver in C-41 films? Or is it only effective on B+W materials?
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    The retained silver test is for AgX not Ag itself, and it will fail. The object of the bleach is to change Silver to Silver Halide and therefore it interferes with the test. We used X-Ray fluorescence, as that was the only test at-hand that worked well.

    PE

  6. #16
    Greg Davis's Avatar
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    I am going to assume that is not something I can do at home.
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  7. #17
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    Greg;

    If you use a bleach within reason and regenerate it by oxidation (even a Jobo can do this with rotary action induced aeration in a blank (no film) run), it will about double the Kodak or Fuji figures if not triple it. The key is overuse and image degradation.

    You can possibly test the bleach by adding some AgNO3 in Acetic Acid. If you get a good cloudy precipitate in fresh bleach, then compare this to a well used one. The well used one will not form as much precipitate. Or try a small piece of copper such as an old copper penny. A bleach should dissolve one. So measure with used bleach. (I have not run these tests with the newest bleach, but have with RA4 blix).

    PE

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