Pyro activator recrystalisation

Discussion in 'B&W: Film, Paper, Chemistry' started by mark snowdon, Feb 18, 2008.

  1. mark snowdon

    mark snowdon Member

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    I have been using pyro developer for some time now without significant problems but have recently found that the activator is coming out of solution forming a crystalline mass at the bottom of the bottle. I use the pyro made by Mike Maunders (UK) which was sold by Creative Monochrome and also Retro Photographic (both UK based). For those not familiar with it, it comes in 2 powders which have to be mixed with distilled water to make the 2 concentrates, like PMK. I do not know the formulation as it has not been published. Has anyone else encountered this problem with pyro activator? I wonder if temperature may be a factor as it has been very cold here in UK – will this cause the recrystalisation? Should the activator be stored in warm conditions?

    Any advice from the many experienced pyro users would be very much appreciated.

    Regards,

    Mark
     
  2. Snapshot

    Snapshot Member

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    Mark,

    The precipitate may be due to cold. I had 10% sodium metaborate solution precipitate form due to frigid temperatures. It's likely that is the case for your pyro activator.
     
  3. Tom Hoskinson

    Tom Hoskinson Member

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    The activator will need to be an alkali.

    According to the Film Developing Cookbook (Anchell and Troop):

    1. PMK Solution B concentrate (the activator) is 1400ml distilled water plus 600 grams of sodium metaborate (aka Kodalk), plus distilled water to make 2 liters.

    It is not unusual for sodium metaborate to precipitate out of solution.

    6 grams of sodium metaborate powder will activate 1 liter of PMK working developer.

    (see page 76 of The Film Developing Cookbook (Anchell and Troop)

    2. The British Journal Pyro-Metol formula Solution B concentrate (the activator) is 750ml distilled water plus 65 grams Sodium Carbonate (monohydrate), plus water to make 1 liter.
     
  4. Trevor Crone

    Trevor Crone Member

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    Hi Mark,

    I now mix my own pyro(PMK) and the activator is sodium metaborate (soln.B). This is mixed to form a highly concentrated solution (300g/litre although I reduce this to 250g/litre) and will almost certainly crystalise at low temperatures.
     
  5. Tom Hoskinson

    Tom Hoskinson Member

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  6. gainer

    gainer Subscriber

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    Another activator that I have tried is triethanolamine (TEA). The 99% variety from www.chemistrystore.com worked as well and in the same proportions as the Hutchings metaborate formula. You should do a test because your personal idea of "as well as" may not be exactly the same as mine. TEA has high viscosity at low temperatures, so I keep a container of it in a warm place.
     
  7. mark snowdon

    mark snowdon Member

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    Thanks for the advice and information. I have sorted out the problem with the Pyro part B – heating the contents of the bottle followed by agitation puts the crystals back into solution. Storage in low temperatures seems to have been the cause of the re-crystalisation.