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  1. #1
    BetterSense's Avatar
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    strange fog with acros

    When hanging up some 35mm acros I noticed what looked like unfixed silver. I had fixed it along with some Tmax so I thought it was odd, since acros has never seemed like a hard-to-fix film to me. After I re - fixed in the same bath, there was no change. I mixed up a hot batch of fix (sprint record speed fix) at 1:3 and tested it with some 35mm film from the floor. It cleared in 30 seconds. After another 5 minutes in the fresh fix, the residue was still there. What could this be? The film expired 2011.
    Attached Thumbnails Attached Thumbnails 20140625_164004.jpg  
    f/22 and be there.

  2. #2
    tony lockerbie's Avatar
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    Very strange, because it looks un-fixed to me, but as TMax usually takes a good minute or more to fix, the Across should have been fine. My experience is that across fixes quickly, like FP4 or Tri-X, so this has me scratching my head.

  3. #3
    MattKing's Avatar
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    Is that dichroic fog?
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  4. #4
    BetterSense's Avatar
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    I have heard of dichroic fog but never seen it. The picture emphasizes the fog...it seems like the negatives might print ok. Is it possible for fixer to be old or spoiled such that it would fix tmax but not acros?
    f/22 and be there.

  5. #5
    MattKing's Avatar
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    Dichroic fog is rarely seen on modern materials. It might be worthwhile to pm Photo Engineer about this.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  6. #6
    BetterSense's Avatar
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    Could this happen if the film was exposed to light between the stop and fix? I have always considered it safe to expose film to room light as long as it was stopped and had been dunked in the fix.
    f/22 and be there.

  7. #7
    Dr Croubie's Avatar
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    Generally, I keep everything in the dark until the first rinse, although it is usually considered fairly safe to bring it into the lights after a few seconds in fixer (at least with paper, I remember my old tech teacher turning the lights on 5 seconds after the last bits of paper were in the fixer at the end of the lesson).
    If, however your first fixer was bad and useless, it would be just like putting the lights on after the stop bath. Whether or not that would cause this problem (at all, plus being on one and not the other) I have no idea though.
    An awful lot of electrons were terribly inconvenienced in the making of this post.

  8. #8
    MattKing's Avatar
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    Quote Originally Posted by Dr Croubie View Post
    Generally, I keep everything in the dark until the first rinse, although it is usually considered fairly safe to bring it into the lights after a few seconds in fixer (at least with paper, I remember my old tech teacher turning the lights on 5 seconds after the last bits of paper were in the fixer at the end of the lesson).
    If, however your first fixer was bad and useless, it would be just like putting the lights on after the stop bath. Whether or not that would cause this problem (at all, plus being on one and not the other) I have no idea though.
    Think about it - even if silver halides in the emulsion are exposed to light in the stop bath stage, when are they going to be exposed to a reducing agent (developer) before they are fixed away?

    As long as the developer in the emulsion has been fully neutralized when the lights go on, it shouldn't be a problem. Essentially, it is a question about how effective your stop bath is.

    With printing, and FB papers, it is much harder to get all of that developer in the emulsion out of the paper, so it is more important to wait.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  9. #9

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    Old film may be the problem.

  10. #10
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    Dichroic fog is a form of physical development, and it occurs - even with fresh and modern film stock - if there is too much solvent in a developer. It's called "dichroic" because it has this yellow-bluish sheen. What you see here is tiny Silver particles that a regular fixer will not remove in a few minutes, and whatever you do to remove it will also attack image Silver to some extent. Since the pics are almost impossible to enlarge this way (see the finger print patterns), you'll have to carefully use some BLIX (C-41 or E6 BLIX, Farmer's reducer, ...) to get rid of it. Make sure you rinse it immediately as soon as the dichroic fog is removed, and rather repeat the removal cycle a few times than remove too much Silver from weakly developed regions.

    As to the reasons why you got this fog: you didn't tell us which developer you used. If it was some normal developer, maybe some fixer got accidentially mixed into it. If you did some experiments with your own brew, go easy on the Silver solvent.
    Trying to be the best of whatever I am, even if what I am is no good.

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