Bleach formula of Kodal Sepia II

Discussion in 'B&W: Film, Paper, Chemistry' started by Andrew Moxom, Jul 25, 2008.

  1. Andrew Moxom

    Andrew Moxom Member

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    Okay, I have been experimenting with the Kodak Sepia II product and have to dilute the Pot Ferri bleach significantly as the stock solution is REALLY active. I dilute to about 1:10. That said, I discard the solution afterwards as I worry about longevity after so much dilution. I find that I use the pot ferri way quicker than the actual sulphide toner and am looking to make my own blend of pot ferri/bromide bleach that mimics Kodaks sepia II product.
    does anyone have any starting points or recommendations for this mix of chemicals?

    Thanks
     
  2. Tom A

    Tom A Member

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    A simple mix for a bleach is:

    Potassium ferricyanide 10g
    Potassium bromide 5g
    Water to 1000ml

    This is working strength.

    Tom
     
  3. Ian Grant

    Ian Grant Subscriber

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    A more common ratio is:

    Potassium ferricyanide 100 g
    Potassium bromide 100 g
    Water to 1 litre

    Dilute 1+9 for use.

    If you use Sodium Chloride in placew of the bromide you get much warmer tones.

    Ian
     
  4. Andrew Moxom

    Andrew Moxom Member

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    Thanks guys
     
  5. dancqu

    dancqu Member

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    Why the bromide, or chloride for that matter.
    After the bleach the silver image exists as the
    insoluble silver ferocyanide. How that image
    might then tone in a sulfide bath I can not
    say. Soon may know though as I've now
    the P. Ferri. and sodium sulfide. Dan
     
  6. Rich Ullsmith

    Rich Ullsmith Subscriber

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    You need rehalogenate the emulsion, or it won't be active in the developer or toner. Pretty sure if you if you bleach without rehalogenating, it goes poof. Like Farmer's reducer.
     
  7. dancqu

    dancqu Member

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    Farmer's reducer has fixer in it. Thiosulfate will dissolve any salt
    of silver. The image should convert to silver sulfide. Dan