PMK pyro, but no stain

Discussion in 'B&W: Film, Paper, Chemistry' started by dario, Jun 25, 2012.

  1. dario

    dario Member

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    Hi folks

    I've just used PMK pyro for the first time. I developed a sheet of FP4+ using the procedure set out in the Book of Pyro, but while the image looks fine, there's little or no stain.

    I mixed up the stock solutions from a pack bought from Photo Formularly and all seemed to be well. The A solution is a very slight straw colour.

    I haven't ever seen a neg developed in PMK, so I'm not sure what to expect. If I look at my neg for long enough I can convince myself that there is a slight yellowish tinge, but that's all.

    I presoaked in distilled water, developed for 10 mins with agitation every 15 seconds, washed in tap water for five minutes, fixed in standard Ilford fixer for 4 minutes, returned the film to the developer (which had turned orange during the course of the development) for 2 minutes, then washed for 25 minutes.

    What am I doing wrong?

    Thanks.
     
  2. PhotoJim

    PhotoJim Member

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    What film? Some, particularly t-grain films, don't stain that much.

    I use a water stop and an alkaline fix, which will maximize stain but from what I understand, a standard acid fix should still leave plenty of stain left.

    Incidentally the returning-the-film-to-the-developer step has been depracated. I have not done this for years and I still get excellent stain. However, I don't use a presoak; I've never had a reason to do so.
     
  3. dario

    dario Member

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    Thanks PhotoJim - As I mentioned, it's FP4+ (4x5).

    On looking at the neg again and putting it beside negs not developed in pyro, the stain is a bit more obvious. Overall, it's a sort of straw colour, including the film edges, but it doesn't seem very intense. Perhaps it's just a matter of me not knowing what to expect.

    I have read about the afterbath being no longer recommended, so might give that a miss in future.

    I don't usually presoak films, but Hutchings gives it as a means of avoiding streaking, so as this was my first attempt, I thought I'd better follow his advice. Certainly the neg seems to be free of any streaks or unevenness.
     
  4. Ian Grant

    Ian Grant Subscriber

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    The colour of the stain varies from film to film so there may be stain but you're just not noticing it.

    Ian
     
  5. dario

    dario Member

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    Thanks Ian. I guess the proof will come when I try to print it. :smile:
     
  6. c6h6o3

    c6h6o3 Member

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    Exactly. Visible stain (or not) on a negative tells you nothing. How the negative prints tells you everything.
     
  7. Michael R 1974

    Michael R 1974 Subscriber

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    I agree it can be difficult to judge by eye, particularly since the stain is proportional to silver density. It should look somewhat greenish-yellow in comparison to a non-stained FP4 negative. FP4 stains quite well in PMK.

    The conventional wisdom is acidic fixers reduce stain. I always used neutral/alkaline fixer with staining developers, but never tried a side by side test with a standard acidic rapid fixer, so I don't know if this is true or not. I just went with the recommendations in The Book of Pyro.
     
  8. Klainmeister

    Klainmeister Member

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    So you made the two solutions.... you need to make the working solution (part A and B) while you do the presoak, otherwise a working solution oxidizes and won't stain well after an hour or two.
     
  9. PhotoJim

    PhotoJim Member

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    Sorry, I missed that you said this was FP4.

    FP4 normally stains very intensely. Plus-X stains a little moreso but also has more general stain. I find the stain on both to be very obvious.

    If you're tube or rotary developing your sheet film the presoak might be more necessary - you can always experiment. For now I'm tray developing with PMK, or developing 35mm and 120 in standard tanks.

    Klainmeister has it right - I'm not sure if you're mixing up your working solution well in advance. You should mix it up immediately before use. I start using it within a minute of mixing it - there's no need to wait. Pour out your water, measure out your A and B solutions (I pour the A into the water as soon as I measure it), and dump the B solution into the A + water as soon as you're ready to develop.
     
  10. JBrunner

    JBrunner Moderator Staff Member

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    1: Skip the "developer after bath". It does nothing but add to B+F.
    2: Use an alkali fixer.
    3: Mix PMK directly before use because it oxidizes rapidly, and even more quickly under agitation.
    4: Make a fat negative to begin with.
     
  11. john_s

    john_s Member

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    The stain I get with PMK and currently with Pyrocat appears subtle compared to some dramatic examples I've seen like these:

    http://www.coxblackandwhitelab.com/pyro.htm

    I attribute this to the fact that I like a well exposed negative that is not very contrasty because my cold light head seems to produce lots of contrast compared to reports of others. The effect of the stain is still effective, though.