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Thread: PMK & Time

  1. #1
    brucemuir's Avatar
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    PMK & Time

    I'm throwing this one out here for discussion in hopes I can gain some knowledge on the way PMK Pyro @ 1+2+100 works (generally speaking because my chemistry is limited at best).

    I've noticed that recommended starting times don't vary a lot except in relation to film speed.

    What I'm getting at is…
    does PMK pretty much soak in and do it's thing to completion and lengthening the time would have little affect on contrast.
    I'm sure it does have an effect but is it as dramatic as say a D76 or Xtol.

    Also any thoughts on the ratios. I've seen a few different recommendations but have always stuck with 1+2+100 because basically I don't know what the ratio differences would do. I do know the part B is the metaborate so I assume this is to regulate the PH for some reason?
    Is that a correct assumption?

    Thanks for bearing with me on my limited chemistry and effects but this is the place to learn and believe me…I DO appreciate all help.

    Happy Holidays and a prosperous New Year's to All.

    Bruce

  2. #2
    payral's Avatar
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    I think the best thing to start would be to read "The book of Pyro" by Gordon Hutchings (1992).
    You will get most of your answers.
    Happy New Year

  3. #3
    brucemuir's Avatar
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    Yes p ayral I inevitably will pick up that book and have had it ready to purchase online several times but something else always took precedence at the time.

    I know it is a good one, and I think it even specifically deals with PMK extensively (Mr Hutchings came up with the Formularys version that I use) which would be helpful to me.

    Really trying to stir some good convo here if anyone has anything.

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    Bruce: You are clearly more experimental than I am! I've been using PMK for something like 20 years, always at 1:2:100, and with relatively minor changes to the recommended times, based on my own testing. PMK does follow an expected time/temperature curve for contrast. My "normal" time is about 1 to 1.5 minutes shorter than the times in the book, because I was consistently getting negatives that were more contrasty than I liked. Hutchings mentions in his book that the curve flattens at the 20 minute mark, developing beyond that adds no more contrast. I've never come close to using a time that long. As for proportions, the only one mentioned in the book is 1:2:100, so that I all I've ever used. (As an aside, since you don't mention the format you use, I've been very happy with PMK for 4x5 and 120 films; for 35mm I prefer D-76 1:1.)
    Regards, Pete Lewin

  5. #5

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    PMK has a short life once it is mixed into a working solution and put to use. In extended-time tests with sheet film processed in trays, I found that it poops out after about 16 minutes due to oxidation. I found that I could get a decent N+1 out of it at the 1:2:100 dilution, but getting to N+2 was difficult. 2:2:100 would double the amount of developing ingredients at the same PH and presumably increase the contrast of the film over the same amount of time as the normal dilution. Increasing the part B would increase the PH of the solution, which might boost contrast, or it might increase fog. You'll have to see for yourself. PMK produces different amounts of visible stain with different films, so it's difficult to predict without actually trying it.

    Information I found about developing times varied widely depending on film type, exposure, development method, agitation. You really have to determine what works best for your own methods. In most cases, I found that about 9 minutes worked pretty well for me using Tri-X and T-Max 100. Delta 100 develops much more rapidly, about 6.5 minutes for normal, all at 1:2:100 dilution, 70 degrees F.

  6. #6
    payral's Avatar
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    Some information from Ron Wisner backup site:
    http://web.archive.org/web/200904240...r.com/pyro.htm
    If you use Tri X sheet film.

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    brucemuir's Avatar
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    Thanks for your experiences guys.
    Okay that makes perfect sense pgomena... regarding oxidation and using ratio to combat the useful life of the developer although I don't think I'll ever need more than 14-15 minutes.
    I haven't used PMK with sheets as I use trays and don't want my hands in that stuff for a protracted amount of time.

    Im using it mostly for 120 and I think I used it with some TMX in 135 awhile back.
    I see people mention they avoid 135 with it but I thought half the idea was for grain masking.
    I just souped some Trix 400 for 12 minutes and although the negs aren't too contrasty I would definitely want to cut back in a situation where there is a large sbr.

    I'm really liking the tonality I'm getting so far with Trix in 120.


    edit: thanks for that link payral

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    Bruce, it does not soak in and go to completion the way a two-bath developer does. It works by time, temperature and agitation the way general purpose developers do. So it is just as important to work out your own film speed and development time with PMK as it is with XTOL, D-76 etc. The difference is that the image density is composed of silver plus dye ("stain"). So it can be difficult to judge the printing contrast of the negative without printing it.

    The reason some people don't like PMK with small negatives is because Pyro negatives are indeed grainier than negatives developed in a general purpose solvent developer such as XTOL, D-76 etc. The grain masking effect of the dye helps slightly.

  9. #9

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    I found PMK with Tri-X 35mm to be very sharp, it produced very good shadow detail, and was quite grainy. With Delta 100, it was smooth and wonderful. It was fine with 120 and sheet films. I use disposable non-powdered latex or nitrile protective gloves whenever I use PMK or Pyrocat-HD. It's not difficult to wear gloves when processing sheet film in trays.

  10. #10
    Bob Carnie's Avatar
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    I have been using PMK for awhile now and here are some of the things I have noticed

    If you want a push developer , I would defer to a different developer.
    The mixed Pyro dev oxidizes really fast... therefore I use two developers 1 liter each and split my normal time for trix into two 7 minute devs and keep the first bottle for stain.

    I will go as high as 16 min for dev and as low as 10 min dev using combined times.
    Mixing with distilled water is critical.
    I have followed Mr Hutching's book pretty much and tend to think the tannin effect is the most important item for this developer.
    For scenes with low contrast lighting ratios I do not see much use for Pyro over other developers
    Different films stain different colour and starting balances when printing tend to differ a bit.

    I will sometimes double the ration and go 20 ml A 40 ml B and 1000 ml water , this seems to give me a boost in overall density, not contrast.
    Pyro works well with a rotary process and is a one shot only process .

    I also believe that low light single source lighting really shows Pyro's capabilities.

    I processed and printed a series of 8 x 10 neg's for Steve Evans that he was commissioned to photograph of the Distillery District here in Toronto before it was transformed into the go to location.
    His exposures were all between 1 second and 1 hour long and these neg's and subsequent prints are IMHO some of the best I have ever done. If the room was lit by a bare bulb we could see detail everywhere and still see the filament inside the bulb with no halitation, or soft muddy highlights.



 

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