Simple Pyro

Discussion in 'B&W: Film, Paper, Chemistry' started by nworth, Jun 13, 2012.

  1. nworth

    nworth Subscriber

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    Gordon Hutchings disclosed a new pyro developer, called Simple Pyro, in the March/April edition of View Camera magazine. See the magazine for details. I haven't tried it yet, but it is certainly simple. It may be possible to mix a stock solution of TEA and pyro (and sulfite), but the diluted solution almost certainly will not keep for more than a few hours.

    Simple Pyro

    Sodium sulfite 500 mg
    Pyrogallol 5 g
    Triethanolamine 10 ml
    Water to make 1 l

    Adjust sulfite to control overall stain.

    Use films at ISO rated speed. Develop as follows:

    EFKE 25 6 min
    EFKE 50 7
    EFKE 100 9
    HP-5 11
    Tri-X 10 min at EI 250
    TMY 10

    EFKE films respond to +/- development. About 25 - 33
    percent change in development is one grade of contrast.

    Ref: Gordon Hutchings, View Camera, March/April 2012
     
  2. Michael R 1974

    Michael R 1974 Subscriber

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    I think this was just one of his early experiments. Pyro on its own typically results in a speed loss, and sulfite needs to be very low for significant imagewise stain.
     
  3. nworth

    nworth Subscriber

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    According to the article. this is a new development. I certainly haven't seen it before.

    I finally got around to actually trying this developer. I tested it on EFKE PL-100M. I mixed it according to the recipe shown above, and developed the film for 9 minutes. For comparison, I also ran some of the same film in D-76 (1+1) for 10 minutes. My guesses about its life seem to be correct. The developer starts turning brown as soon as you add the TEA. When I poured the developer out after developing the film, it was a bright brownish-red. I'd say it's only good as a one-shot with a mixed life of an hour or so, but I haven't really tested this.

    The developer produces very nice looking negatives with the characteristic yellow-green pyro stain. Densitometry shows it has slightly lower contrast and a longer straight line section than D-76 (1+1) with this film. I ran desitometry tests with both white and blue light (I do not have a UV densitometer.) The curves are almost exactly parallel, except at the highest densities. The stain seems to just add density, not contrast. Under 50X magnification, Simple Pyro produces negatives that are very slightly grainier than D-76 (1+1), but they are also noticeably sharper.
    Simple Pyro Test.jpg
     
  4. Michael R 1974

    Michael R 1974 Subscriber

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    So based on your blue/white channel measurements it looks like general as opposed to imagewise stain. Would you say film speed is lower or about the same as D76 1+1?
     
  5. nworth

    nworth Subscriber

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    You can get an idea from looking at the raw data. The density difference between the top an bottom step is 1.53 for white light and 1.59 for blue, so there is some image stain effect, but probably not much. King has pointed out, however, that effects can be greater in the ultraviolet. As for emulsion speed, there is no toe area to get real speed point measurement, but from the low density data I would estimate that D-76 gives about half a stop more speed than Simple Pyro. The step tablet exposures were based on EI 100, reading the light box intensity and opening up 5 stops. This works well enough to give useful curves, but there are enough uncalibrated things involved that I wouldn't rely on it for real speed measurements.
     
    Last edited by a moderator: Jun 21, 2012
  6. Michael R 1974

    Michael R 1974 Subscriber

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    Thanks for posting the tests. Interesting stuff.
     
  7. jim appleyard

    jim appleyard Member

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    Do we have a good & cheaper substitute for TEA? I know that very little is used, but at $10/pint, I'd hate to go and buy it find that I don't like the developer.
     
  8. desertrat

    desertrat Subscriber

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    I guess you could use clear household ammonia, with no sudsy stuff added, but it's kind of unpleasant stuff to work with in an open tray in a darkroom. I tried using pyro and ammonia once on some Efke R100 in 120. I got images, but I got better results with other developers.
     
  9. Rudeofus

    Rudeofus Subscriber

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    I would strongly advise against ammonia in developers and your results support this. Ammonia may fog your film and it is a strong silver solvent compared to a tertiary amine like TEA.

    @jim appleyard: Don't worry about the US$10 for a pint of TEA. If you really don't like the results, you've also wasted at least one roll of film, some fixer and a lot of time, so the US$10 should not be the biggest issue. Besides there are plenty of decent rev recipes where you can use up the remaining TEA, e.g. DS-10, DS-12 and here is one with pyro.