Curved Streaks on Film

Discussion in 'Film and Processing' started by kenneth_swoyer, Feb 4, 2016.

  1. Hello Forum Members!
    I've been reading this forum for years but this is my first post. I tried to see if this question had come up but cannot find anything - if I'm using the wrong search terms, my apology.
    I've been shooting on a used Nikon FM2n for about two years. On every roll I've taken in for processing it has been returned with curved streaks on a few of the photos. Not many, but 2-3 and it's bumming me out. Here is an example (see the darker lines to the right of the taller tower):
    [​IMG]
    At first I thought maybe it was a lens issue. But I'm using three different lenses and see no regular patterns. Then I thought it was poor processing. I've taken film to three different places and it has happened with each one of them. Then I thought it might be a camera issue but I'm not quite sure how this could be caused by rubbing or something like that.
    Anyway, has anyone encountered anything like this? Am I just having bad processing luck? Maybe a leak in an iris (again this has happened with multiple lenses)?
    Thank you in advance!
    -Casey
     
  2. I'm wondering if this is a shutter problem. The FM2n has a vertically traveling focal plane shutter, and the leading or trailing edge may follow a patter like that. There could be some damage to the edge of the leading or trailing shutter blade that makes the edge protrude extra into the traveling slit of the shutter. If that was the case, this would happen only at the highest shutter speeds (like 1/2000 and 1/4000), where the slit is narrow enough that the roughness could be a significant percentage of the slit width.
    Another possibility is that the shutter is bent, and is scraping against the film on some exposures.
    The FM2 series has very thin very light shutter blades to get a high X-sync speed, and high top shutter speed. Easy to damage, particularly with a stray finger when loading film.
     
  3. Let's see if we can narrow the cause down more. When looking at the negative on a light table with a loupe, what are you seeing in the affected areas? Can you see any physical damage to the negative? Do the streaks extend into the rebate (edges) of the film? My first suspect is camera, but for the life of me I can't think of anything that may cause something like this. Is the film commercially rolled, or do you load your own? Is it the same type and batch of film each time? Were all the same rolls processed by the same lab? Does the size of the streaks change, or are the streaks identical in size, shape and location?
    I'm sure we'll figure it out.... :-/
     
  4. I read in the camera's specs it has a vertical-travel, metal focal plane shutter. Perhaps the shutter somehow brushes the film from time to time. My best guess.
     
  5. I would agree with both Johns', it's probably being caused by the arm that moves the shutter blades. IIRC, it moves in an arc pattern, so it's probably time for a CLA and repair.
     
  6. You might also check the pressure plate on the back. If it's misaligned it could push the film onto the shutter
     

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