Drying marks on film

Discussion in 'Large Format' started by neil_miller|1, Mar 20, 2002.

  1. Please help me! I am having terrible trouble with drying film - the sheets look OK after they come out of the wash, but dry with outlines of runs and areas of lighter/darker density where water has drained off. The puzzling thing is some sheets come out perfectly! On average, about 50% of the sheets I dry are affected to a greater or lesser extent by these marks.

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    I've tried everything I can think of - the water in my area is hard and used to leave chalky deposits, so I tried deionised water which was a bit better. I then invested in an RO system which eradicated the deposits entirely and has almost resulted in no drying marks at all on roll film, however sheet film is still affected and so is 35mm to an ever greater degree.

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    I have used a tank to wash the film in with water feeding in from the bottom and out at the top. I have used wetting agent and found even more marking and runs. I have tried hypo eliminator at the correct interval during the washing sequence and am not sure that it has had any noticeable effect.

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    For 5x7 sheet film I leave the film in the unicolor drum after processing and rinse with 600mm of water on the motor base for 1 minute. This is emptied out and another rinse (same vol.) for 2 mins, followed by 5 more rinses of 5 mins duration each rinse. The film comes out clearer and more evenly developed than I've ever seen it, but after drying in my durst hot-air dryer it has these horrible marks all over it.

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    I know the marks are caused during drying as I can see from the gelatin where the marks will be - where the water has cascaded off the sheet, following a roughly diagonal path echoing the way the film has been hung. The marks are on the emulsion side - the other side is perfectly clear. The marks will not wash-off - they have become areas of low density in the middle of the mark with a ring of darker density at the fringes.

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    I hope some of you can help, as this is driving me nuts - all my careful work and planning is being ruined by something that I have semmingly no control over.

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    Sorry about the rant.

    <p>

    Neil.
     
  2. Do your final treatment after washing in Photo-Flo mixed in distilled
    water. Use only one half as much Photo-Flo as recommended on the
    bottle, as too much of it will leave residue on the film.
     
  3. I personally purchased distilled water to mix with my chemistry, make
    sure that I give my fix about 25% more time than my film developer
    time (T-Max film to make sure that the anti halation layer gets
    completely eliminated in my drums), keep my washes short at two
    minutes each (in my JOBO) and use a minimum of ten washes and do not
    use any hpo eliminator of photo flow at all. Because my new darkroom
    is still about two months from completion, I just air dry the negs in
    my bathroom after introducing a short amount of humidity into the air
    by running the shower for a short period. I make sure that my forced
    air furnace does not kick in during the drying period. My negatives
    come out clean and completely without drying marks and dust. Good
    Luck
     
  4. I had the same problem - my film had drying streaks on certain frames
    that left the densities uneven. I then tried what a previous post
    already mentioned - the final step of photoflo mixed with distilled
    water - it worked, and the negatives had even density and no
    streaking.

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    I took the older film which already had the streaks, resoaked it,
    then applied the photoflo and distilled water, and they dried fine.
    So I recommend that you do that with your film that has the problems -
    hopefully it will work for you, and you won't have any lost negatives.

    <p>

    Good luck!

    <p>

    James Webb
     
  5. I agree with 1/2 the amount of Photoflo but if you have a decent photo
    store nearby, get some LFN. It is made by Ethol or Edwal. All you need
    is a drop so by the small dropper! It works great in the pre water bath
    also. Really breaks the tension in the water.
    Cheers
     
  6. Try drying them without the hot air. That is let them dry over night
    after a bath in a photo flow water. In my experience you have to
    be carefull with Ilford and especially Agfa.
     
  7. I almost wonder if what you have are development marks and not the
    effects of drying.

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    I had some serious problems with Agfa 120 films. I had processed
    thousands of 35 mm
    rolls (literally I worked for a newspaper) without any trouble but I
    often would get
    uneven development with 120 film processed the same way. So I
    started to use a running
    water pre-wash as well as stop bath. (Stop bath wasn't even
    AVAILABLE to use at the
    newspaper! Not that it mattered) After these changes my film
    development problems went completely away.

    <p>

    The use of stop bath was suggested just so the development was
    instantly halted over the
    entire surface of the film. We hacks had just used a water rinse
    between developer and
    fixer and with the bigger negative perhaps some development was
    still progressing on
    parts of the film area, while it had stopped (so to speak) on some
    areas.

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    The next time I became unhappy with development was when I started
    processing 8x10
    film. I had been using a Unicolor drum and roller to process two
    sheets of 4x5 film at a
    time. I used about three ounces of developer solution and had been
    getting good results,
    so I tried it with the 8x10 and had really bad, uneven development.
    Everyone I talked to
    recommended increasing the volume of developer solution so now I use
    about eight
    ounces. I've increased the volume of volume of developer solution
    for 4x5 as well since I
    think that I was sailing pretty close to the wind with just three
    ounces.

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    I should add that I use a running water pre-wash for all of my film
    processing from 35
    mm (now that I'm no longer a hack) right up to 8x10.
     

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