pyrocatechin two bath.

Discussion in 'B&W: Film, Paper, Chemistry' started by el wacho, Mar 12, 2008.

  1. el wacho

    el wacho Member

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    hi,

    anyone used or heard of this?

    source website at the bottom ...

    BARRY THORNTON'S 2-BATH FORMULA
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    Bath A

    Pyrocatechin 10 g

    Sodium sulphite 2 g

    Potassium bromide 0.5 g

    Water to make 100 ml




    Bath B

    Potassium hydroxide 10 g

    Potassium bromide 0.5 g

    Water to make 100 ml




    Working solutions:

    Mix 1 part A + 14 parts of water (4 minutes)

    Mix 1 part B + 14 parts of water (4 minutes)

    Do not rinse between baths!

    Retrieved from "http://www.photocrack.com/photovergne_wiki/index.php/BARRY_THORNTON%27S_2-BATH_FORMULA"
     
  2. sanking

    sanking Member

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    Yes, I experimented with that formula some years ago. I think it is one of the experimental formulas that led to the two-bath Diaxactol Formula of B. Thornton that is sold by Formulary.

    My advice would be to substitute the 10 g of potassium hydroxide with 40 g of potassium carbonate. I liked this better than the formula as stated because the working pH is much lower and grain seemed a bit finer.

    Sandy King



     
  3. el wacho

    el wacho Member

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    am i right in thinking that after the A B baths are used, they are to be discarded? if so you'll chew through 10g of catechol in no time..

    mr King,

    what kind of modifications could be made to the A bath so that it could be used as a reusable stock A bath ( eg diafine, where the baths A and B are returned to thier respective containers. )..

    any info to point me in the right direction would be much appreciated.


    ta.
     
  4. sanking

    sanking Member

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    I was thinking about Diafine myself. Thornton recommends disposal of the mixed baths, but that may not be necessary, so long as you don't shift the film from one bath to the other. If you do, the working baths will surely degrade in a fews hours. So will Diafine if if you mix the A and B solution.


    Sandy