chromium intensifier

Discussion in 'B&W: Film, Paper, Chemistry' started by sly, Oct 16, 2007.

  1. sly

    sly Subscriber

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    I have some thin 4x5 negatives I'd like to boost a bit. There is shadow detail, just not much separation between tones. The problem was developer temperature, I think. They were tray developed in Rollei Low Speed developer - 22 minutes. Even though I put the tray in a warm bath for the development, they both cooled during that extended time. My darkroom is in an outbuilding, not the house. (Wasn't a problem during the summer - go figure :rolleyes: )
    When I bought my enlarger one of the things thrown in the box was an unopened package of chromium intensifier. I'd like to know if I can use Agfa multicontrast developer or Ilford Multigrade rather than the recommended Dektol. I bought a couple of gallons of the Agfa when our last local source for such things was closing shop. The Ilford was thrown in the box with the enlarger and is of unknown age (haven't tried to use it yet.)
    Thanks in advance for any help, Sly
     
  2. Monophoto

    Monophoto Member

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    Probably. Try it on one negative to see what happens.

    Chromium intensifier requires that the negative be bleached. That's a pretty aggressive step, and before going to that extreme, you might try selenium toning one of your negatives to see if that would give you enough of a contrast boost. IIRC, the recommended dilution for intensifying negatives with Kodak Rapid Selenium Toner is 1:1.
     
  3. sun of sand

    sun of sand Member

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    I just tried some myself the other day
    I bought the stuff just to get familiar with options out there/experiment
    The little foil pouch with bleach got wet somehow -probably years ago-
    I was sure it was trash
    I chopped and smashed up the chunks of bleach and tried dissolving the stuff, anyway
    I went through some coffee filters

    It still bleached the 4x5


    It worked
    Not too much of a difference

    Maybe if printing on graded paper it would help? Don't really know



    I'll try selenium one day ..it does 2 things for you.
     
  4. gainer

    gainer Subscriber

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    IIRC, selenium toning is pretty good protection against anything else happening to your negative, so if the first time doesn't do it, get out your #4 contrast filter or get some #4 paper.

    I use the rehalogenating bleach such as is used with sulfide toning with redevelopment in a staining developer. This can be very simple, as redevelopment will be to completion. As long as you're not concerned about particular printing materials, an MQ or PQ solution with little or no sulfite will stain quite well. The proportions are not critical. Sulfite inhibits staining, so use very little or none at all. The process can be repeated to intensify the stain. The silver part of the image remains. Too much repitition may cause stress cracks in the emulsion due to the tanning action.
    What else does selenium do besides make your hair fall out?
     
  5. gainer

    gainer Subscriber

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    I forgot to mention that the stained image WILL respond to high contrast printing filters on VC paper, as well as to graded papers.
     
  6. Ian Grant

    Ian Grant Subscriber

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    If you use your Chromium Intensifier on a B&W print and redevelop in a simple Pyrocatechin developer you get wonderful olive brown tones. This is the basis of Ilford IT-8 toner published in the Ilford Manual of Photography.

    Ian