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Thread: Fixer precipitate and Marks on Negatives

  1. #1

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    Fixer precipitate and Marks on Negatives

    Hello all,

    I unfortunately used some fixer that had developed some precipitate gunk to fix some negatives yesterday, and want to know how I can remove it from my negatives. It's regular Kodak fixer w hardener, so it's sodium thiosulfate, sodium metabisulfite, and potassium alum for hardener. I have no idea what the precipitate is, but it looks kind of like little flakes. I tried soaking the negs in distilled water, and also refixing, and neither worked. Is there something else I can try? I remember reading that sodium carbonate is used for de-hardening prints. Assuming the precipitate is related to the hardener, could that possibly work? Thanks for any suggestions,

    GB

  2. #2
    Resident Heretic Bruce Watson's Avatar
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    Re: Fixer precipitate and Marks on Negatives

    Quote Originally Posted by G Benaim View Post
    Hello all,

    I unfortunately used some fixer that had developed some precipitate gunk to fix some negatives yesterday, and want to know how I can remove it from my negatives. It's regular Kodak fixer w hardener, so it's sodium thiosulfate, sodium metabisulfite, and potassium alum for hardener. I have no idea what the precipitate is, but it looks kind of like little flakes. I tried soaking the negs in distilled water, and also refixing, and neither worked. Is there something else I can try? I remember reading that sodium carbonate is used for de-hardening prints. Assuming the precipitate is related to the hardener, could that possibly work? Thanks for any suggestions,

    GB
    Little tiny black flakes? That would likely be metallic silver. It's part of the emulsion now. Sorry. I've lost enough negatives like this that I now use fixer as a one-shot (just like developer) to eliminate this problem, which it has.

    Bruce Watson

  3. #3

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    Re: Fixer precipitate and Marks on Negatives

    Hi Bruce,

    This was actually fresh fixer, though it sat unused for about a month.

    GB

  4. #4

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    Re: Fixer precipitate and Marks on Negatives

    You might try asking this question over on APUG. Perhaps "Photo Engineer" can provide an answer.

    Good Luck,

  5. #5
    Resident Heretic Bruce Watson's Avatar
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    Re: Fixer precipitate and Marks on Negatives

    Quote Originally Posted by G Benaim View Post
    This was actually fresh fixer, though it sat unused for about a month.
    Seen odd things with fresh fixer too. I had some old-fresh fixer that I started to use that had little mostly clear bits floating on the top. The bits were quite small, long and thin and pointy on the ends. Maybe a millimeter long. But I saw it before I used it so I didn't end up with any on my negs. I called Kodak about it and they couldn't tell me anything about what it was or what caused it to form which isn't really surprising since all they had was me on the phone. If they'd had samples...

    I'd second searching APUG and if you can't find an answer post a question there. Photo Engineer is a great source, but he's also a busy source. But there are other resources there too.

    But back to your original question... if it's stuck to your emulsion it's pretty likely permanent. I've tried various ways to get stuff off and found that most every effective method was also destructive. So prevention is the best bet.

    What I did was to become a cleanliness fanatic. At least twice a year I clean the darkroom from ceiling to floor drain. Every wall, every surface, under shelves (you'd be surprised), everything. Then I switched to one-shot chemistry for film. Developer, stop, fixer, all of it. One shot. Then I switched to distilled water for mixing. Then extended that to washing. Then extended that to a policy that only distilled water touches the film or the film side of the equipment. Then I made sure that drying equipment was drying in an orientation such that what little dust there was couldn't dry on surfaces that film touches.

    It's maddeningly obsessive. But with each step my dust problems went down. I knocked down the incidence of crap on my negs by about 95%. Still not completely clean, but much better. And I'd rather be obsessive on the process side than spend hours and hours dust spotting after the fact.

    But that's me. Clearly YMMV.

    Bruce Watson

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