Recognize this HCA recipe?

Recognize this HCA recipe?

  1. craigclu

    craigclu Subscriber

    Messages:
    871
    Joined:
    Sep 8, 2002
    Location:
    NW Wisconsin
    Shooter:
    Multi Format
    craigclu submitted a new resource:

    Recognize this HCA recipe? - Recognize this HCA recipe?

    Read more about this resource...
     
    Last edited by a moderator: Feb 6, 2016
  2. Ian Grant

    Ian Grant Subscriber

    Messages:
    18,114
    Joined:
    Aug 2, 2004
    Location:
    West Midland
    Shooter:
    Multi Format
    2% Sodium Sulphite works just as well. The EDTA will help with some hard water. It's not that critical it's not a hypo eliminator just an aid for shortening wash times.

    Ian
     
    Last edited by a moderator: Sep 15, 2008
  3. john_s

    john_s Subscriber

    Messages:
    1,110
    Joined:
    Nov 19, 2002
    Location:
    Melbourne, A
    Shooter:
    Medium Format
    It looks a lot like Richard Knoppow's "believed to be" close to the Kodak, but double strength (1+9 for working strength) instead of 1+4. I mix it double strength too, making it easier to store.

    This quote either from rec.photo.darkroom or pure-silver:

    <start of quote>The purpose of the sequestering agents is to eliminate a tendency of the sulfite bath so form a sludge with alkaline salts in the water, probably not necessary when the wash aid bath is not used to its capacity. You can make your own wash aid. The formula below is not official but is pretty close to what is in KHCA.
    Sodium Sulfite, dessicated 100 grams
    Sodium Bisulite 20 grams
    EDTA tetra-sodium salt 1 gram
    Sodium Citrate 1 gram
    Water to make 1 liter

    The above is a stock solution. For use dilute one part stock to four parts water.

    <end of quote>

    RK has said that there is some doubt in his mind about the citrate and EDTA levels. He said he didn't know if his figures for these were pre- or post- dilution.

    The quantities of citrate and EDTA in your formula are different. Ryuji Suzuki also had a formula with different amounts of these two minor ingredients, and I think Wolfgang Moersch here at APUG had yet another. Maybe it can be found.
     
    Last edited by a moderator: Sep 16, 2008
  4. john_s

    john_s Subscriber

    Messages:
    1,110
    Joined:
    Nov 19, 2002
    Location:
    Melbourne, A
    Shooter:
    Medium Format
  5. john_s

    john_s Subscriber

    Messages:
    1,110
    Joined:
    Nov 19, 2002
    Location:
    Melbourne, A
    Shooter:
    Medium Format
    And from Ryuji Suzuki's web site a similar formula (working strength):

    <start of quote>
    A standard washing aid is:
    Washing Aid
    sodium sulfite 15g
    sodium metabisulfite 5g
    water to make 1.0 l
    target pH 6.5 to 8

    When scum is formed on the solution or processed material, addition of about 0.5g/L of disodium or tetrasodium EDTA with about 1.0g/L of sodium citate is suggested. Stock solution including the EDTA and citrate tends to keep longer.

    Kodak Hypo Clearing Agent contains EDTA and sodium citrate to reduce the calcium scum. With hard water, sulfite in the wash aid forms insoluble calcium scum unless EDTA is added. These are also useful in preventing precipitation of aluminium hardener that may be carried over from the fixer (if acid hardening fixer is used).
    <end of quote>