Negative "curl"

Discussion in 'B&W: Film, Paper, Chemistry' started by like2fiddle, Dec 3, 2007.

  1. like2fiddle

    like2fiddle Member

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    I recently bought a roll (100ft) of Tri-X and am experiencing something I had not experienced previously with a bulk roll of HP-5. After processing and air drying the exposed film, the negatives are curling edge to edge, to the point that they are difficult to insert into negative holders and darn near impossible to scan on a flatbed scanner. As I mentioned, this has never been a problem with HP-5. I also experienced this, much more severely, with an expired roll of Plus-X I just developed. I wonder if, being winter here in Vermont, the air is so dry that the film is drying too fast. :confused: Even the HP-5 is doing this more than it used to. Any ideas/advice?
     
  2. Trevor Crone

    Trevor Crone Member

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    Try using heavily weighted film clips on the bottom of the film strip when hanging to dry.

    A tempory measure is breathing on the upper surface of the film this should start the film to curl uppermost. It only lasts for a while but might be long enough for you to get it under the flat bed or in the file sheets.
     
  3. wilsonneal

    wilsonneal Member

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    I recently had several rolls of TX120 that curled (slightly) in the wrong direction. I am accustomed to film cupping a little toward the emulsion side. These rolls are flat to curving a little toward the base side.
    N
     
  4. like2fiddle

    like2fiddle Member

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    Thank you Trevor, I'll give that a try. I actually did switch to unweighted plastic clips on the lower end of the film when drying. The strip looks nice and flat while drying, but perhaps the added weight will help permanently set it flat.
     
  5. highpeak

    highpeak Member

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    I think the film dried too fast. Also some weight at the bottom helps a lot.

    Alex W.
     
  6. like2fiddle

    like2fiddle Member

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    This is what I am leaning toward. I will add some weight and see what happens. Interestingly, I tried a roll of Fomapan, which I had never tried before, and it seems to have a thicker base and curled less. The worse cupping, and curling, as in spiral-like, has been the Plus X.
     
  7. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    I have never had any severe problems with curling of the film base in the 35mm format, but I have had some film in 120 format go nuts on me. Some of them, Foma for instance, curl like mad no matter what the weather is like (high or low humidity), others like Agfa and Ilford, dry almost perfectly flat. What I have discovered, however, is how effective it is to dry the film in a smaller room with a steam humidifier in it. Now that gives super-flat negatives.
    I agree the weights help a lot, and that putting the film in Print File sleeves and putting them under weight is another good suggestion. I'm actually surprised that Kodak curls like you say. That's a brand that's been particularly good in that regard (to me).
    Now I have a room that's very cold in the winter, around 50*F. So the film still dries slow enough that I don't have to worry about curling, unless it's a quality of the film base itself, like 120 Foma film.

    - Thomas
     
  8. Tony Egan

    Tony Egan Subscriber

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    In my recent experience Ilford 35mm films are curling a lot more than Kodak and Fuji. The base seems to be a little thinner than it used to be? I've only had the problem you mention with Ilford films but not Kodak. I use heavy weights and after going into sleeves I generally leave under a pile of heavy photo monographs overnight. I also concur that fast heat-assisted drying also compounds the problem.
     
  9. greybeard

    greybeard Member

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    Not long ago I needed to examine 20--30 rolls of 35mm Plus-x and Tri-x that had been stored since 1967 in the attic of a barn in Alabama, rolled tightly and wrapped in paper. The film was wound into rolls about the size of my thumb, and wanted to stay that way. In order to get them into a scanner, I cut each roll into strips, and used pieces of scrap mounting board to hold them flat on a larger piece of mounting board, with tape keeping the assembly together (but not touching the actual film). The whole works went into a warm dry mounting press with barely enough pressure to hold things snugly; the press was heated just really warm to the touch, and then powered off. After the press had cooled (an hour or so) the film came out flat and (amazingly) entirely undamaged.

    I can't say that I would recommend this for anything important, but in this case it was sort of a last-ditch effort, since the film was so curly that it was almost impossible to examine with a loupe, and getting it into a negative carrier would have been even more likely to damage it. It was probably fortunate that the film had been in a low-humidity environment for months before I tried this; I suspect that in Alabama humidity it would have picked up texture and/or particles from the mounting board. If I absolutely had to do something like this on good film, I think that I would use strips of very clean silicone release paper to protect the negatives, and make sure that everything was good and dry before starting.
     
  10. like2fiddle

    like2fiddle Member

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    Thank you all for your replies thus far. I've placed several sheets of negatives under a couple of heavy books for the last two days, and that has seemed to help tremendously. I do think much of the problem has to do with the lack of humidity in the air (we have a woodstove, and it's been fairly cool lately so the air is relatively dry) hence the film dries quickly. Additionally, that Plus X was expired some time ago and had therefore been sitting rolled-up in a cassette for quite some time. I can't explain the new Tri-X curl except for the dry air. I'm going to try weighting the drying film more to see how much that will help.
     
  11. George Collier

    George Collier Member

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    To follow up on Greybeard's method (I have a cigar box full of rolls from my father, taken in the 40s and 50s stored the same, but at room temp) - How about sandwiching the film in acid free board as you suggest, but inside the board, also inside individual folds (both sides of the film) of glassine paper? I've been told that this is a good material for shielding fiber prints when flattening just as you describe, which works well for me (for prints).

    I can test it on film, of course, but I've never really known the composition of glassine material, or it's possible long term effect on emulsions. The heat, as you state, is just enough to feel warm to the hand.
     
  12. greybeard

    greybeard Member

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    George,

    I have negatives that were stored for 50--60 years in glassine envelopes, and they don't seem to have suffered from it. I mentioned silicone release paper because it is very smooth and is pretty much guaranteed not to stick to anything that might have gotten onto the film. If you aren't in a hurry (I needed to know quickly whether the film had anything of immediate interest) you could put the film in a folded strip of either glassine or release paper, and just store it flat under pressure for however many days, weeks or whatever that it takes to flatten out. Heat would accelerate the process, but isn't otherwise necessary. Agfa used to make strip-form glassine sleeves that were assembled like a Venetian blind, and I found one that I had left in a book for a few months. The negatives were just as flat as could be (this would have been 1970s-vintage Tri-x 35mm).
     
  13. George Collier

    George Collier Member

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    Greybeard,
    Thank you for your reply. Actually, I have taken a sample roll from the group I mention, put it into a long Printfile sleeve (the length of the roll). I then took the sleeve and wound it "backwards", emulsion out against the curl, around a small tube (like a paper towel core), left it for months, and when removing it, it returned almost immediately to the curled condition. I assumed flat would do no better.
    I'll try the heat.