Pyrocat HD negs and platinum printing times

Discussion in 'Alternative Processes' started by Ray Bidegain, Jun 21, 2004.

  1. Ray Bidegain

    Ray Bidegain Member

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    I would like to a technical question, of those of you that are using pyrocat HD for you platinum printing. I have been using it for a bit and really like the fact that my negatives for platinum print well in silver as well. The issue I am having is that the printing times for the platinum are way too long. In the area of 30-60 minutes. I have a home made light box that prints a TMY D-76 neg in 8-10 minutes. Are you finding your exposures to be this long, or am I way over exposing the negatives. I don't think that I am over exposing but I can't explain the long times.

    Any feed back on your experiences would be greatly appreciated.

    Ray Bidegain
     
  2. Mateo

    Mateo Subscriber

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    Which film?
    I had the exact same problem with Ilford HP5 but FP4 and efke Pl100 are closer to my standard 12 min exposure. I went back to Abc because it's easier to see my films status in developement.
     
  3. Jorge

    Jorge Inactive

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    Pyrocat has a greater UV absorption that any other developer, this is why it is so wonderful for pt/pd, you can get high contrast with little effort. Although not apparent in the negative, you are overdeveloping for alt printing. ease down a bit on the development and you will see the negatives print just as well.

    My tests show me that Pyrocat absorbs from 1 to 1 and 1/2 stops more UV light, so if you have really dense negatives I am not surprised at your times.
     
  4. sanking

    sanking Member

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    There should be very little difference in printing times between well exposed and properly developed negatives developed in Pyrocat-HD and a non-staining developer such as D76 or Xtol. Printing times are determined by shadow density, and since stain is proportional to silver density, lowest in the shadow areas and highest in the highlights, there should be little difference in density in the shadows between a negative developed in Pyrocat-HD in contrast to one developed in a traditional developer.

    My own negatives developed in Pyrocat-HD print in about 8-10 minutes with a bank of BLB tubes, with the tubes about 5" from the printing plane. High speed films (HP5+, Tmax 400, etc.) develop more B+f than slow and medium speed films and for this reason may need slightly longer development times. Very long exposure times (and 30-60 minutes is quite long) could result from several conditions.

    1. Over-exposure. If you over-expose by one stop you more than double your printing times.

    2. Use of slightly fogged film. As film ages, or if left in high heat for too long, it develops a higher B+f from fogging. This can easily add a stop or more to your exposure times with a staining developer like Pyrocat-HD.

    3. Too much agitation in development can also lead to higher B+f levels.



    Sandy King
     
  5. Ray Bidegain

    Ray Bidegain Member

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    Thanks for all your help, I am going to try less exposure in camera and see if it helps.

    Ray