Pyrocat HD - Sodium carbonate instead of Potassium carbonate?

Discussion in 'B&W: Film, Paper, Chemistry' started by Baxter Bradford, Oct 25, 2005.

  1. Baxter Bradford

    Baxter Bradford Member

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    When ordering chemicals for my first attempt with Pyrocat, the chap from Retrophotographic didn't stock Potassium Carbonate and persuaded me that I could use Sodium Carbonate instead. Any advice on how this might affect development/film speed kindly appreciated.

    I see from unblinkingeye an addendum that:
    "Mr. King has modified solution B to use a 100% solution of potassium carbonate instead of a 10% solution of sodium carbonate. An earlier version of the formula published on the rec.photo newsgroup called for 2.5 grams of metol in place of the phenidone. Mr. King suggests that this formulation may be more stable than the phenidone version. The keeping time for solution A when formulated with phenidone is about 3-6 months. Ted Kaufman has recommended substituting a 10% solution of sodium hydroxide for solution B."

    There is no more explanation than that, not we have become accustomed to on APUG!

    I want to keep things as simple as possible, having no desire whatsoever to reinvent wheels, just to reap the rewards of others' hard work. I do now have a digital pH meter if this is any help in adjusting dilutions etc to keep things as close to the mainstream as possible.
     
  2. Baxter Bradford

    Baxter Bradford Member

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    Leon kindly found some information contained in the article by Sandy King that has rendered this thread unnecessary. Here is the ref.

    http://unblinkingeye.com/Articles/PCat/PCat2/pcat2.html

    I apologise for my inaccurate statement about there neing no more information. Quite the contrary it seems.
     
  3. John Z.

    John Z. Member

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    I use the metol listed in the article instead of the phenidone--easier to work with in my opinion. I also use the sodium carbonate. When I have tried the Potassium carbonate on a few occassions the negatives seemed softer--lower contrast overall. Anyone else noticed this?
     
  4. Donald Miller

    Donald Miller Member

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    I use sodium carbonate as well. When using sodium carbonate, the amount of water used must be increased five fold because saturation on NaCO3 is much lower then KCO3...
     
  5. Ole

    Ole Moderator Staff Member Moderator

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    I get around the whole "B" sodium/potassium carbonate solubility problem by not making a "B" at all. Instead I dissolve the necessary amount of carbonate for the final soup in the water, then add "A". One less bottle to keep around.
     
  6. Baxter Bradford

    Baxter Bradford Member

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    Thanks for the info. Am looking forward to getting going on this. Seems I was panicking too quickly.

    Ole, I am intending to use your Quick Fix - OF1 so thanks for the help on this too.