Jobo & Pyrocat split quantity

Discussion in 'B&W: Film, Paper, Chemistry' started by Wilfried, Jul 22, 2004.

  1. Wilfried

    Wilfried Member

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    I'd like to use Pyrocat in a two step development using a Jobo processor with a 3005 Expert drum. If I normally use 800ml of developer for 14 minutes, would I need to use 2x800ml for 7 minutes each or 2x400ml for 7 minutes each?

    Wilfried
     
  2. sanking

    sanking Member

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    If you can slow the rate of rotatin down to 10 RPM or less you should not need to do split development with Pyrocat-HD under any circumstances.

    I would only do split development if normal development were resulting in excessive B+f. With most films this would not be the case, even with high RPM speeds.

    However, if you are getting excessive B+f and are not able to slow down the rotation I would recommend dividing the 800ml of developer into two units and do 2X400 ml seven minutes each or a total of 14 minutes. This assumes that the 400 ml will be enough to provide complete coverage of all of the films being developed.

    Sandy King
     
  3. Wilfried

    Wilfried Member

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    Thanks for your help, Sandy.

    The slowest speed of my processor is 26rpm; my film is TMY 8x10. I can do all my development in one step, except for N+2, which works best if I split it.

    Regarding your last statement ("This assumes that the 400 ml will be enough to provide complete coverage of all of the films being developed.") - how much would that be per 8x10 sheet (using 2:2:100)?

    Thanks,
    Wilfried.
     
  4. sanking

    sanking Member

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    I calibrate my procedures on the basis of about 250 ml per 8X10 sheet, or the equivalent, of the 2:2:100 dilution.

    And yes, if the slowest speed of your processor is 26 RPM and the film is TMY I think split development might help to cut down on B+f. TMY is one of those films that develops a lot of general stain with fast rotary development with pyro staining developers.

    However, there are ways to slow down the rotation of your Jobo so you might also want to look into that for the sake of convenince. I don't use Jobo so can not give any details but maybe someone else will.

    Sandy King