Proper dilution of Kodak Rapid Fixer Solution A ???

Discussion in 'Kodak' started by Phil Glaser, Apr 28, 2004.

  1. Phil Glaser

    Phil Glaser Guest

    Hi,

    I need to dilute Kodak Rapid Fixer solution A only (for fixing prints
    that are to be toned) and am unsure as to the proper dilution. I see
    one place on Kodak's web site that says 1:3 (which sounds correct for
    film but not paper), another that says 1:7). Then again, I've
    extrapolated from the instructions that come with the fixer (which
    include instructions only for dilution with solution B) and my results
    don't match either 1:3 or 1:7 (but I'm mathematically challenged).

    What is the magic ratio?
     
    Phil Glaser, Apr 28, 2004
    #1
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  2. Phil Glaser

    Jazztptman Guest

    Phil, If you are using a longer fixing time (2-4 minutes for RC and 5-10' for
    fiber base papers) in a tray and do not need a hardening fixer, you can use the
    paper dilution of 1 portion of Part A to 7 portions of water. If a
    non-hardening fix is prerred, use Part A only - Part B is the hardener.

    The more concentrated 1:3 ratio is used in rapid roller transport B&W paper
    processors with fix and wash times in the range of 20 seconds each. Only part A
    is used in this application as the hardener would shrink the emulsion and not
    allow proper fixing or wash to take place in such a short time.
    Bernie
     
    Jazztptman, Apr 29, 2004
    #2
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  3. Phil Glaser

    Phil Glaser Guest

    I need to clarify some things Both the fixer and paper instructions
    suggest that the fixing time with rapid fixer is 1 minute for RC,
    whereas the instructions for Kodafix suggest 2 minutes for RC. So when
    you say to fix RC for 2-4 minutes, is it because the directions are
    not conservative enough, or because leaving out the hardener
    necessitates a longer fixing time? I would have hoped that, with
    _rapid_ fixer, I would not have to fix for as long as with Kodafix.

    The other thing is that I what I am starting with is not the powder,
    but the liquid concentrate of Part A. Do I still use 1:7 part A to
    water with the liquid concentrate? Ther reason I ask is that the
    instructions suggest the relative amounts to make one gallon (which is
    way more working solutiion than I need at any given time) and it does
    not look to me like the dilution, based on extrapolation, would work
    out to 1:7.

    Thanks!

    --Phil
     
    Phil Glaser, Apr 29, 2004
    #3
  4. Phil Glaser

    Jazztptman Guest

    Phil said: I need to clarify some things Both the fixer and paper
    instructions suggest that the fixing time with rapid fixer is 1 minute for RC,
    whereas the instructions for Kodafix suggest 2 minutes for RC. So when you say
    to fix RC for 2-4 minutes, is it because the directions are not conservative
    enough, or because leaving out the hardener necessitates a longer fixing time?
    <<
    Phil I was going by memory. I think you're correct and Kodak calls for 1-2
    minutes with RC papers.
    long as with Kodafix.<<

    Kodafix (the liquid concentrate) is also a "rapid" ammonium hypo fixer. Not
    much different from Rapid Fixer. The only "slow" fixer Kodak has is the powdred
    Kodak Fixer, which is a sodium hypo fix.
    liquid concentrate of Part A. Do I still use 1:7 part A to water with the
    liquid concentrate? Ther reason I ask is that the
    instructions suggest the relative amounts to make one gallon (which is way more
    working solutiion than I need at any given time) and it does not look to me
    like the dilution, based on extrapolation, would work out to 1:7.<<

    Yes, 1:7 for the liquid concentrate Rapid Fixer. 1 part of part A concentrate
    to 7 parts water.The directions probably also call for some part B which is why
    the volumes do not work out to an exact 1:7 dilution. Good luck and have fun
    printing.



    Bernie
     
    Jazztptman, Apr 30, 2004
    #4
  5. Rapid fixers can cause bleaching of fine grain silver
    images typical of paper prints if the paper is left in them
    longer than necessary for fixing. For that reason most
    manufacturers of "rapid" fixers give two dilutions: one for
    film and another for paper. For film, which is more
    difficult to fix than paper, the usual dilution is 1:3 or
    1:4, for paper the dilution is 1:7. The fixing time is about
    doubled when paper dilution is used. If you are a careful
    worker in the darkroom you can use film strength rapid fixer
    for paper, but beware that the fixing time will be between
    30 seconds and 2 minutes, depending on the paper. When rapid
    fixer is used in a neutral form it does not bleach so the
    whole issue becomes moot. If no hardener is used the fixer
    can be neutral. Agfa color fixer is neutral pH rapid fixer.
    Also, Kodak Rapid Fixer with Hardener, can be used without
    the hardener added. The pH is less acid this way (but I
    don't know what it is) so there is less chance of bleaching.
    With alum hardener the pH of a fixing bath is around 4.5.
    Hardener is not needed by many of today's films and
    papers which have much harder emulsions than those of some
    years ago. The hardener prevents excessive swelling of the
    gelatin in the fixing bath and wash. For emulsions that are
    soft and swell excessively the presence of a hardener can
    actually decrease fixing time by shortening the diffusion
    path fresh fixer must take to get into the emulsion and
    fixer reaction products must take to leave it.
     
    Richard Knoppow, May 3, 2004
    #5
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