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  1. #11

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    I got this private message from Ian C,which I found very helpful:

    "I’m surprised anyone thinks that 2-bath fixing is controversial. I read the recommendations and the reasons for doing so many years ago in books written by the personnel of Eastman Kodak. I believed then as I do now that they were the most authoritative source of photography materials knowledge. I started darkroom work in 1987. One of my coworkers gave me a single film-developing and printing lesson in his darkroom. He used single-bath fixing. He told me that people who process a greater volume usually use 2-bath fixing, but he didn’t do that. He simply discarded his fixer after 25 8” x 10” prints. It works, provided you’re good at keeping track of the number of prints you’ve fixed and don’t “cheat”. After I’d done this a couple of years, I noticed that some of my older Kodak Polycontrast prints had ugly purplish stains on them. It takes a few years of reaction with the oxygen in the air for this to become evident, but then it’s too late.

    I did some reading of Kodak books. The stains matched their descriptions of “inadequate fixing”. Further reading suggested that I could eliminate the problem by 2-bath fixing. I practiced this from that point on and never had another stain-ruined print. You may already know this, but I think it’s worth repeating. In 2-bath fixing, fix 1 does the majority of the work, even if it has become weak. Then bath 2 only has to dissolve any small amount of unexposed silver salts that remain. After 25-30 8” x 10” prints (2000-2400 sq. inch) you scrap fix 1 and the partially used fix 2 becomes the new fix 1. Of course you need a new fix 2. You repeat the process every 2000-2400 sq. inches of processed paper. In this way you always have a relatively strong fix 2 ready to intercept any unexposed silver salts still remaining in the print after fix 1. It’s a clever idea, gives you maximum use of your fixer, and guarantees complete fixing so that you prints are permanent with respect to fixing. I can’t imagine why anyone would do otherwise."

  2. #12
    RalphLambrecht's Avatar
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    Quote Originally Posted by mts View Post
    ...Fixing is either complete or not...
    The problem is, fixing is never entirely complete. To decide on two-bath over one-bath fixing depends on how complete you want it.

    During fixing, undeveloped non-image silver is dissolved by thiosulfate without damaging the metallic silver image. The first fixing bath does most of the work but becomes increasingly contaminated by the soluble silver thiosulfate and its complexes. Soon, the entire chain of complex chemical reactions cannot be completed successfully, and the capacity limit of the first fixing bath is reached. A fresh second bath ensures that all remaining silver halides and silver thiosulfate complexes are dissolved. An intermediate rinse is optional, but it protects the second bath from contamination. Fixing time must be long enough to render all residual silver halides soluble, but not so long as to allow the fixer and its by-products to permeate the paper fibers; the former being far more important than the latter.

    So, one-bath fixing works, but it has some disadvantages: longer fixing times, fixing never as complete as two-bath fixing, residual fixer penetration deep into the fibers, leading to longer and not as effective print washing.

    Quote Originally Posted by mts View Post
    ...If you are not re-using fixer you are unlikely to exhaust the one bath...
    Correct, but if you do not change the fixer after every print, you are reusing fixer.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  3. #13

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    Quote Originally Posted by RalphLambrecht View Post
    So, one-bath fixing works, but it has some disadvantages: longer fixing times, fixing never as complete as two-bath fixing, residual fixer penetration deep into the fibers, leading to longer and not as effective print washing.
    Do you say that two bath fixing time is shorter than one? Could you please explain? What is your personal procedure?

  4. #14
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    Quote Originally Posted by wiggywag View Post
    Do you say that two bath fixing time is shorter than one? Could you please explain? What is your personal procedure?
    Yes, two-bath fixing is shorter than one. Take your current one-bath fixing time and split it in half. Now fix sequentially for that time in two baths (where the 2nd is always fresh), and your print will have less residual thiosulfate than with the previous method, because the 2nd fix is always fresh. Consequently, you can fix for less time with two-bath fixing to get the same result.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  5. #15

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    Quote Originally Posted by RalphLambrecht View Post
    Yes, two-bath fixing is shorter than one. Take your current one-bath fixing time and split it in half. Now fix sequentially for that time in two baths (where the 2nd is always fresh), and your print will have less residual thiosulfate than with the previous method, because the 2nd fix is always fresh. Consequently, you can fix for less time with two-bath fixing to get the same result.
    Im not getting this perfectly. Say my normal fixing is 5 minutes with one bath fixing. I then split the time in half, 2.30 minutes. This is my new fixing time. 1.15 minutes I use in the first bath and 1.15 minutes I use in the second bath. Is this the way I should understand it?

  6. #16
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    OK, quick question.

    If I start double bath fixing today with 2 fresh batches of fix, where the recommended rate is 40 sheets, would I ultimately use the original second bath for 80 sheets before it gets discarded? (does that make sense? It does in my head! )

  7. #17
    RalphLambrecht's Avatar
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    Quote Originally Posted by wiggywag View Post
    Im not getting this perfectly. Say my normal fixing is 5 minutes with one bath fixing. I then split the time in half, 2.30 minutes. This is my new fixing time. 1.15 minutes I use in the first bath and 1.15 minutes I use in the second bath. Is this the way I should understand it?
    No. If your single-bath fixing time is 5 minutes, split it in half and fix for 2 1/2 minutes in each fixing bath with two-bath fixing. It's just that the two bath fixing will fix more thoroughly and fixing for two times 2 minutes will be sufficient as well. So, 5 minutes once turns into 2 minutes twice.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  8. #18
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    Quote Originally Posted by hoffy View Post
    OK, quick question.

    If I start double bath fixing today with 2 fresh batches of fix, where the recommended rate is 40 sheets, would I ultimately use the original second bath for 80 sheets before it gets discarded? (does that make sense? It does in my head! )
    Yes, the 2nd bath fixes 40 sheets as 2nd bath and afterwards 40 sheets as 1st bath before it gets discarded. However, measuring silver content is better than counting sheets, and if you count sheets, don't forget to count test strips too.

    A little hint:
    Don't discard your old fixer after a printing session. Discard it in the middle of the session, after test strips and work prints are done. This way you get fresh fixer for the final prints.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  9. #19
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    any comments on on ILford's archival fixing recommendation ... basically highly conc. fix for very short times ?
    Miles :
    cherish light

  10. #20
    Ian Grant's Avatar
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    Yes, it works, very well.

    Ian

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