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  1. #1

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    residue on Negatives

    I am always getting some sort of scum or deposits on my negatives (Tri-X 8x10) after they dry. I use photo flo and dilute it out as I know this helps, but still always some crap on my negs. It is a white caked deposit of sorts. It seems never to affect printing but it bugs me. Could these deposits eat away at the film over time? How do I remove them? Thanks in advance.

    Jordan

  2. #2

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    I wonder if it's mineral deposits - do you mix your photo-flo with distilled water?
    Emancipate yourselves from mental slavery;None but ourselves can free our minds. - Bob Marley

  3. #3

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    I'm pretty sure it is mineral deposits. I have not used distilled water till now, but have already washed this whole batch. How can remove these deposits?

  4. #4

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    Quote Originally Posted by Jordke View Post
    I'm pretty sure it is mineral deposits. I have not used distilled water till now, but have already washed this whole batch. How can remove these deposits?
    Not really sure how to remove them once they're there - maybe PE has a suggestion. The first thing I'd try is re-washing them in distilled water.
    Emancipate yourselves from mental slavery;None but ourselves can free our minds. - Bob Marley

  5. #5
    nick mulder's Avatar
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    I'm certainly no expert and am getting these occasionally myself, usually on the emulsion side - I see them but they dont turn up in contact printing - odd, I mean being opaque they must right ? but they dont, noticeably enough in any case ...

    On a neg that was ruined for other reasons I tried using a microfibre cloth on them to see if they would remove without scratching - I got almost all off apart from a leftover ring which to remove by forced rubbing did crimple the neg ...

    Rewashing doesn't help - ah well, I'm trying both hardener and a new brand of photo-flo soon - see if that helps
    Cleared the bowel problem, working on the consonants...

  6. #6
    Akki14's Avatar
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    I use a very lightly damp piece of tissue to wipe off drying marks if they're on the NON-emulsion side. I don't tend to get weird marks on the emulsion side.
    ~Heather
    oooh shiny!
    http://www.stargazy.org/

  7. #7
    Dave Miller's Avatar
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    If they are mineral deposits, and that seems most likely, then using distilled water for your final rinse (with or without photoflow) should mitigate the problem.
    Regards Dave.

    An English Eye


  8. #8

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    As Dave and others have already said use distilled or de-ionised water as a final rinse will almost certainly solve the problem.

    To remove the stubbon mineral deposits I've resoaked negatives in a standard acid stop bath this will dissolve the calcium deposits found particularly in hard water areas. Just rewash as normal no need to fix.

    An excellent wetting agent a friend gave me the 'heads-up' on is Rollei's RWA super concentrate wetting agent. I found I no longer have to use distilled water or squeegee my films. I just hang them up to dry naturally and they dry beautifully clean and clear.

  9. #9
    Justin Cormack's Avatar
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    I never found photo-flo worked enough (London is a hardwater area). Using deionised water for the last rinse is fine though, and I can buy it easily down the road (sold for car batteries). Stop bath ought to remove them, but prevention is better than cure.

  10. #10
    Joe VanCleave's Avatar
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    I have had issues in the past with both water marks and dust/debris, or some residue, on my dried film. I process both rollfilm and sheet film. I don't have a bona fide film drying cabinet, however, and my darkroom is located in a corner of my otherwise dusty/much used garage.

    What I've found that consistently works for me is I transfer the rinsed film in a closed container (plastic 'tupperware'-type with lid, for sheet film, or the developing tank for rollfilm) from the darkroom to my small bathroom. The bathroom is prepped before hand by removing all towels and throw rugs (it has ceramic tile on floors and halfway up the walls), and then I run the hot water in the shower for several minutes. I set up a metal curtain rod in the shower, dedicated for this purpose, along with metal bulldog clips, with metal hangar wires, that are also dedicated for this purpose.

    Once in the enclosed bathroom, I mix DI water, 91% IPA (isopropyl alcohol, not India Pale Ale; that's for later) and one or two drops of Photoflow. I mix it gentle but well (to avoid sudsing), then each sheet of film is repeatedly dunked and allowed to drain off, several times, before hanging in the shower. For rollfilm I repeatedly dunk the film reel (gently to prevents sudsing of the Photoflo), and gently pull the film off the reel, squeegy with two fingers of my prewetted hand, and hang got dry with a counterweight on the bottom of the roll to permit it to drain properly. Then close the shower door to minimize intrusion of air. For sheet film I also place the tupperware dish of IPA/DI on the floor of the shower stall, below the film, with the idea that the IPA vapors from the liquid will contribute to the drying effect by scavenging additional moisture from the surface of the film. If I had a dedicated film drying cabinet I would do this there.

    I keep this bathroom closed up for several hours, with the bright lights on to add a bit of heat without stirring up the air.

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