Just inherited some PMK pyro

Discussion in 'B&W: Film, Paper, Chemistry' started by wilfbiffherb, Jul 6, 2012.

  1. wilfbiffherb

    wilfbiffherb Member

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    hi,

    i bought a darkroom kit a while ago for printing and with it i got a laod of chemicals. i have been using rodinal exclusively for the last few years but now i have microphen, perceptol,ID-11 and some PMK Pyro. to be honest im not up to speed with any of these developers but the pyro really interests me. the shots i have seen posted online look great (not sure how much of that is the pyro compared to the print). can anyone tell me how ebst to use it and how long the shelf life is? i have 2 batches that come in powder a and powder b.

    thanks
     
  2. vedmak

    vedmak Subscriber

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    First thing about powder is be real careful while mixing it, pyro is a toxic chemical, second if you do mix it use distilled water, pyro usually lasts a very long time even in liquid form. The times for pmk are available at digital trugh website. Usually it is recomended using non alkaline fixer, and water instead of the stop bath in order to maximize the stain, you also might want to put film back in the used developer after you fix it, again to improve the stain.
     
  3. Michael R 1974

    Michael R 1974 Subscriber

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    The other developers you listed are all solvent developers. PMK Pyro (and Pyro developers in general) is an acutance developer. It will give you sharp negatives with more grain as a tradeoff. It is a staining developer. Depending on the film, it will give the negatives a greenish stain which is proportional to the silver density. When printing, the stain increases the effective printing density. This means that the printing density in the negative is the sum of metallic silver density and stain density. Because of this, the silver density can be lower than in conventionally developed negatives. This is an important point. It means that compared to what you are used to seeing in a normally developed negative, a negative developed properly in PMK will appear lower in contrast to your eye. So, particularly when starting out with Pyro, it is important to print your negatives in order to evaluate whether they have been exposed and developed properly. It is hard to judge the negatives by eye.

    The lower silver density, combined with the stain, helps reduce graininess to some degree - although people tend to overstate this effect.

    PMK is a little more tolerant than early conventional Pyro formulas, but still needs carefull attention in processing to avoid streaking and uneven development. Proper agitation is critical.

    To maximize proportional stain ("imagewise stain"), it is generally best to keep the process neutral or alkaline in pH. Use a water stop bath procedure rather than the usual acid stop bath. It is debatable whether or not it is necessary to use a neutral/alkaline fixer rather than a standard acidic rapid fixer, but the conventional wisdom is not to use an acidic fixer. You do not need to put the negatives back in the used developer as is sometimes recommended. Wash with water as usual - don't use a hypo clearing agent.

    These are just some basics but hope it helps.
     
  4. c6h6o3

    c6h6o3 Member

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    My experience with staining developers, and I've used a lot of them, is that for the most part they contain way too much stain. Even if there's no fog stain a developer like PMK can have unmanageable contrast from all that stain. I wouldn't worry about trying to increase proportional stain at all.

    I use ABC pyro with a strong acid stop and Ilford Hypam fixer. I still get what I consider to be too much stain (sometimes). Image stain seems to be a very inconsistent thing.
     
  5. PhotoJim

    PhotoJim Member

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    I find PMK negatives easy to print. If the stain is adding too much contrast, that's an indication of overdevelopment.

    Pyrogallol is slightly toxic so you may want to wear gloves while processing with it.

    I've been using PMK for 11 years now and it's one of my favourite developers. It works well, and the stock solutions last for years.
     
  6. wilfbiffherb

    wilfbiffherb Member

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    thanks for all the info guys. been printing a lot lately so its probably time to get shooting and mix up some pyro!