Homebrew Hardening Fixer?

Discussion in 'B&W: Film, Paper, Chemistry' started by rknewcomb, Apr 11, 2008.

  1. rknewcomb

    rknewcomb Member

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    Hello,
    I'm using Efke 25 film in 4x5 and 8x10 size and trying to process it without getting scratches. Many have said that it has a soft emulsion and a hardening fixer is needed. I could use regular kodak fixer or the Kodak Rapid fix that has hardener but I have two issues with that.
    1) I would prefer to mix my own fixer from sodium thiosulfate because it is cheap to make and also because my darkroom sessions are sometimes spaced far enough in time that a freshly made fixer seems like a good idea vs whats been sitting in the bottle since the last time.
    2) The odor of Kodak fixer is fairly strong for my darkroom that is located in my house.
    So, can I just add some Kodak hardening solution to my homebrew fixer? I have some from the past when I've used the rapid fixer without the hardener plus there are hardeners that can be mixed from scratch.
    Is there a less smelly hardening fix that I can mix in smaller batches?
    I also asked this question on the Large Format list, but thought more people might be able to help if I also asked here.
    thanks for the help.
    Robert newcomb
     
  2. Aurelien

    Aurelien Advertiser Advertiser

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    You can buy Tetenal Hardener. You have just to put it in your fixer. That is what I do with efke ad sometimes with Foma films in 120, in order to avoid curling.
     
  3. Paul Verizzo

    Paul Verizzo Member

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    No!

    The separate hardener is of the aluminum sulfate kind. Most hardening fixers use acetic acid, which is why they smell. I just checked my (never used) bottle of hardener that comes with Rapid Fixer. It is sulfuric acid, aluminum sulfate, and water. I'm not going to give it the whiff test, that would mean breaking the seal and it might leak. Not sure even why I keep it.

    It will not work, or work well, in plain hypo, pH about 6. It needs to be more acidic.

    I think, emphasis on think, that formalin does not require an acid fixer. PE, where are you? Also, you can fix in your hypo and then harden in a subsequent bath. And don't worry about freshness of fixer. If it has 15 grams of sodium sulfite per liter (all prepared and normal formulas have it), it will keep nigh unto forever. Well, almost, anyway. If in doubt, test it with a film clip.
     
  4. rknewcomb

    rknewcomb Member

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    I couldn't find a place in the US that sells the Tetenal Hardener, plus I don't know how it is different then the Kodak hardener which is easy to find but Paul says won't work due to a ph problem.
    Could I change the ph of my straight hypo so the hardener could then be used?
    Could I simply make a separate hardener bath to be used after the fixer?
    Or, could I buy the Koday Rapid fix in liguid form and just mix smaller batches as needed?
    Robert N.
     
    Last edited by a moderator: Apr 11, 2008
  5. Paul Verizzo

    Paul Verizzo Member

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    "Could I change the ph of my straight hypo so the hardener could then be used?" Yes. Sodium metabisulfite, acetic acid, sulfuric acid, citric acid, etc. How much? Look to published formulas for guidance or buy pH test strips.

    "Could I simply make a separate hardener bath to be used after the fixer?" Yes, that's what I was saying. While combining hardener with the fixer is a long time tradition, it adds other complications in washing, i.e., takes more time. Frankly, my take on the chemistry is that it is a stupid decision. Someone might feel otherwise.

    "Could I buy the Koday Rapid fix in liguid form and just mix smaller batches as needed?" AFAIK it is only available in liquid form. Use 1:4 film strength for film and paper, there is no logical reason to dilute further. Don't worry, it will not go bad for many years if stored in normal heat. If you use an acid stop bath or good water bath before fixing, there is nothing there to cause oxydation. It's not developer.
     
  6. Tom Hoskinson

    Tom Hoskinson Member

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    I shoot and process a lot of Efke 25 and Efke 100 film (35mm, 120 rollfilm, 4x5 sheet film, 5x7 sheet film and 8x10 sheet film)with no emulsion damage (no nicks, no scratches no dings). I NEVER USE A HARDENER OR HARDENING FIXER. I use TF-4.

    Sacrifice some film, practice with the room lights on and learn how to handle the film without damaging it. ONCE THE THE EMULSION IS DAMAGED, HARDENER WON'T FIX IT.

    If you can't learn how to handle the film without damaging it, then you couild pre-harden it (with one of the Formalin or Formaldehyde based prehardeners).

    BUT YOU WILL STILL NEED TO LEARN HOW TO HANDLE THE FILM WITHOUT DAMAGING IT in order to pre-harden it - take one of Michael and Paula's workshops if you can't learn how to do it by yourself.
     
  7. Photo Engineer

    Photo Engineer Subscriber

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    If you wish to use a hardening fix, it must be at pH 4.5 and use either acetic acid or sulfuric acid. The odor is mainly a mix of acetic acid + sulfur dioxide from the Sodium Sulfite used as a stabilizer. In the other direction, you can use an alkaline fix at pH 8 or 9, with formaldehyde or one of the other aldehyde hardening agents.

    Either way, you have an odor.

    Tom is right. Learn to handle film, or use a harder film such as from Kodak, Ilford or Fuji.

    PE
     
  8. juan

    juan Subscriber

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    I've processed a lot of Efke film and I've found that damage to the emulsion can occur at any stage in the process. A hardening fixer will only help during the fix and wash - you film could be badly scratched before then. Efke film can be discouraging, but if you learn to handle it correctly, as Tom and PE have said, you can be successful. Plus, you'll know that you are also handling all your other film correctly.
    juan