Hang-dry film - how long?

Discussion in 'Black and White' started by peter_langfelder, Oct 17, 2002.

  1. Methylated spirit is about 95% ethanol, with the addition of pyridene to give it an incredibly bitter taste, and methylene blue dye, which gives it its name. Contrary to popular belief, it doesn't contain methyl alcohol.

    Ethyl alcohol is quite deliquescent and difficult to keep 'pure' without it absorbing a fair percentage of water. Anyway, I was generally in no desperate hurry to dry my film. So such pyrotechnic shenanigans were a one-off experiment.

    FWIW. Last time I processed Tmax100 (about a year ago) I was surprised how quickly it dried - only about an hour until it was touch dry. That was after finger-squeegeeing the surface water from it and at room temperature ~ 21 degrees C.
     
    Last edited: Apr 30, 2021
  2. Methylated spirit seems not to be a common US name, so I was just suspecting it was methanol based.

    For ethanol, 95% is the best you can do with distillation, and so that is what you commonly see.
    The bottles that you get for lab use have a tax stamp on them. (In the US, anyway.)
    Higher than 95%, they have impurities that you don't want to drink, and no tax stamp.

    I remember learning this in a thermodynamics class, where the professor explained to us,
    which one to get when raiding the lab before a party.

    In the US, we have "denatured alcohol" which is ethanol with some things intentionally
    added that you don't want to drink, and that are also not easy to separate out.

    From: Denatured alcohol - Wikipedia

    it seems that methanol was, at least once, one of the additives, up to 10%.
    The can I have of "denatured alcohol" also claims a methanol addition.

    Otherwise, yes, I often find them dry to the touch pretty fast, but let them dry longer to be
    sure that they are dry all the way through.

    We have a heat pump water heater, which keeps the basement both cool and dry.
     
  3. In the newspaper business during the film days we often used denatured alcohol to quickly dry film when we were trying to get sports photos out under deadline. We weren’t worried much about long term effects on the negatives but then two of the photographers were often smoking cigars while printing so it was a unique environment all around.

    Rick H.
     
  4. I know this is an old thread, but I'll add my input. After washing negatives I let them soak in Photoflow solution for 30 seconds then hang them up. Usually dry in 2 to 3 hours. My darkroom receives air (heating or cooling) from central HVAC so humidity never gets too high.
     
  5. If you want that it dry rapidly, use isopropyl alcohol with a few drops of Photo-Flo as last bath. It dries in minutes.
     

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