light leaks using 120 roll

Discussion in 'Medium Format Cameras and Accessories' started by pellicle, May 9, 2008.

  1. pellicle

    pellicle Member

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    Hi

    I'm getting intermittent light leaks down my film which I suspect is caused by improper tension on the take up roll. My camera is a Bessa 6x9 folder, which I do not believe has any leaks itself. The film door has quite a reasonable light seal, and there are no other signs of light leaks in this camera.

    I've noticed that the design of the camera has a small pair of springs either end of the spool at the supply side reel to keep tension as well as a small curved spring which seems to 'grasp' the reel. These seem ... well flimsy. The take up spool has only the small curved spring.

    I've recently bought another camera (a Holga) which has a small foam pad stuck on the inside where the take up spool is, this seems to wind the reels much tighter (applying greater friction as well as pressure).

    I'm wondering about modifying the Bessa to include this feature.

    Alternatively it could be light from the 'red window' ... however this would then (in my opinion) appear on every frame (as I wind on with the window uncovered every frame) rather than just at random (if at all) intervals.

    anyone have any thoughts on this?


    sample image

    [​IMG]
     
  2. xtolsniffer

    xtolsniffer Member

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    I got the same thing when using an old Cononet Captain 120 format camera from the 1950's. When I took the roll out, it was wound really loose on the take-up spool so I got the same light leaks as you, basically because light was leaking in at the edges of the wound-up roll. I bent the spings in a little which helped, but I still have the problem, so all I do is take the film out under a coat (or in a changing bag if I can be bothered to take it out with me), then pop the film into a light-tight tin. Then in the darkroom take it out in darkness. Of course if you're not developing yourself, the lab won't know this.
     
  3. ricksplace

    ricksplace Member

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    My experience has been that the tension on the supply spool is more important than the take-up spool. If the tension on the supply spool is solid, the tension on the take up spool will be too. When you load the film, hold the supply spool with your finger to induce tension. Keeping the supply spool tight might solve your problem.
     
  4. pentaxuser

    pentaxuser Subscriber

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    I have an Agfa Isolette I which out of about 20 rolls has exhibited what I believe to be a loose roll once. As you say if it were the red window which I have as well, it would show up on several or even all frames. Having said that I'd still be inclined to wind on with the window in shade and make sure that the metal cover over the red window,if you have one, is then pushed back into place. It stuck me that the red window over many years may lose its safe light quality slightly and certainly having a strong sun shine on it isn't sensible. If you only have a red window and no further protection I'd stick a piece of black or silver tape over the window.

    I made sure this time that I held the supply spool down with a finger while pulling the backing paper onto the take-up spool and once I had wound on the film at the end, I opened the back in subdued light and held the spool tightly while extracting it. It might be enough to simply then pull the backing paper extra tightly before using the gummed label but if I were not to unspool and develop almost straight away I'd now be inclined to try and find a 120 film holder and place it into that. Then not open it until I was in darkness and ready to feed onto the developing reel.

    That cured the problem and demonstrated that on the previous occasion it was simply a loose roll and not a light leak from the camera back or bellows.

    OK this is belt and braces stuff but no great hassle and such precautions pay dividends.

    pentaxuser
     
  5. pellicle

    pellicle Member

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    Folks

    thanks for the helpful suggestions. I've only used 35mm (tight cassettes) and 4x5 (lisco film holders) so moving to 120 is a learning curve in some ways.

    After reading the suggestions here and based on my experience with the foam blocks in keeping the takeup spool tight I'm strongly suspecting the lack of tension provided by the Bessa takeup. I'll be looking into making a slight modification in this area.

    thanks :smile:
     
  6. max_ebb

    max_ebb Member

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    If there isn't enough resistance on the supply spool to keep tension on the film as it winds onto the take up spool, then film flatness might also be an issue.