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  1. #1

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    Stannous chloride foggant recipe

    I'm online from my basement, developing a roll of Agfa Apx100 as slide.
    I've used this foggant recipe:

    Part A (buffer):
    1000ml water
    16ml acetic acid 80%
    32g sodium acetate trihydrate

    Part B:
    1000ml water
    0,5g stannous chloride

    So far so good: the image is uniformly fogged. The problem is: the part A + part B after a while turns cloudy, especially after being used.
    Is it normal?

  2. #2

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    1) I° developer: Fomatol P 1+0 + 4g/400ml hypo + 20ml Rollei RMB5;
    2) stop: 2% acetic acid;
    3) wash 5-10-20;
    4) bleach: 2g/1000ml potassium permanganate + 55g/1000ml sodium bisulfate;
    5) wash 5-10-20;
    6) clearing: 25g/1000ml potassium metabisulphite;
    7) wash 5-10-20;
    8) foggant: foggant recipe (acetic acid/acetate buffer) + 0,2g/400ml stannous chloride;
    9) wash 5-10-20;
    10) II° developer: D76 1+0 + 20g/1000ml sodium carbonate;
    11) wash 5-10-20;
    12) fixer 1+9;
    13) wash;
    14) selenium toner 1+20;


    temperature: 19°C
    1) 12min, 5 inversions every minute;
    2) 1min
    4) 5min 1 inversion every 15 seconds;
    6) 3min, 5 inversions every minute;
    8) 2min, 5 inversions every minute;
    10) 6min, 5 inversions every minute;
    12) 4min, 5 inversions every minute;
    14) 4min, 5 inversions every minute.

  3. #3
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    With use, as acidity drops, it can become cloudy. A chelating agent would probably help.

    PE

  4. #4

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    Acidity drops mean that pH goes below the buffer pH?
    I've designed the buffer to have approx pH 4.6. Now the question is: how can the foggant bath go below pH 4.6?
    There's a buffer to prevent it...
    And the step before is water so there's not any alkaline or acidic carry-over...

  5. #5
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    Well, SnCl2 can do this SnCl2 (aq) + H2O (l) is in equilibrium with Sn(OH)Cl (s) + HCl (aq) and this can cloud up. It can take place even in acid.

    Adding some ETDA should help.

    PE

  6. #6

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    Ok, got it.
    Another chemical powder on the buy list!
    :-))

    So, if I measure the pH after the bath has turned cloudy, I should get a reading below 4.6 right?
    Tomorrow I'll try.

    P.S.: glutaraldehyde works wonders!!!

  7. #7
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    It might be 5.0 or higher by now, but the formation of the precipitate goes on, once started and in the absence of a chelating agent. That is the purpose of the other ingredients in the Kodak reversal bath. It prevents the precipitate from forming.

    PE

  8. #8

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  9. #9
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    Very nice.

    PE

  10. #10

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    There's something wrong with my pic above.
    Maybe too much hypo...

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