Possible Light Leaks

Discussion in 'Large Format Cameras and Accessories' started by Silverpixels5, Sep 9, 2003.

  1. Silverpixels5

    Silverpixels5 Member

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    I think I'm having problems with light leaks in my 5x7 gear, but I'm not positive where they are coming from. On two negatives I have what looks like overexposed spots...covering the small area like fog. At first I thought perhaps it was the film holder, but the exposure pattern is exactly the same on both negatives, which would mean both sides of the holder would have to be flawed in exactly the same way on both sides...not likely. So then I'm thinking that its the way this holder was sitting, or sits, in the camera since the leak is at the very edge and goes inward about a cm or less. Does this sound about right? Anything I can do to correct it, or will I just have to toss the holder? thanks!
     
  2. Donald Miller

    Donald Miller Member

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    If the same spot is being overexposed on both negatives then you are likely to have a problem apart from the holder. If the orientation is opposite each other (from side to side) then the holder may be involved. Does it occur on the "notch" end of the film? Or is it at the light trap area? I thought that I had problems with holders as well a while back. I found that I had pin holes in the bellows instead. I found this by loading a holder into the back, removing the lens board and holding a lit flashlight in the camera in a darkened room. Good luck.
     
  3. Silverpixels5

    Silverpixels5 Member

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    It runs along the edge of the film lengthwise. But it does so on both negatives which is why i didn't think the flaw was in the holder. I didn't suspect bellows leak since it is new, but perhaps it isn't attached correctly at the end, so I'll check that out. I'll try what you did, and see how it goes. Thanks!
     
  4. Jim Chinn

    Jim Chinn Member

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    Double check to see that the spring back is keeping the holder in contact with the back. Also check where the bellows is connected to the rear standard. I don't recall what camera you have but if the bellows is held on the standard with a retaining plate and screws, they may be worked loose, or you may have some sort of seperation of material at the back of the bellows on the side of the over exposure.

    Another possibility is the holder frame could have some build up of gunk in the corners or foreign matter imbedded, especially if it is wooden. So check rear frame for dirt.

    Just to make sure on the holders, use a straight edge and check for warpage. A slightly bowed holder could allow a light leak where it seats to the frame.

    I suggest these only because I have run across all of them at one time or another on various cameras of mine or those of friends.
     
  5. Silverpixels5

    Silverpixels5 Member

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    Thanks for the tips. I'll try all of them when I get home today. The camera is a 5x7 Agfa Ansco, with a new bellows. The bellows is attached with screws or adhesive I think. Its an all wood camera, and the film holders(kodak) are wood as well.
     
  6. glbeas

    glbeas Member

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    I've had fog like that from the film being fogged in the box somehow, just one edge of the film was lightstruck. Never found out how that happened, maybe some curious person peeked into the box while I was away.
     
  7. Silverpixels5

    Silverpixels5 Member

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    Well I think I found out the problem with one of the holders (only tested one so far). I did the flashlight thing in the dark with one of the holders in and it seems that if the holder isn't sitting perfctly along the top then light can creep in at the corner...for this holder. The exposed part of the negative for this holder was at the corner as well so I think thats the only leak...for that holder. I have the other holder which had the leaks along the top edge of the film, which means the leak should be coming from the bottom edge of the camera, so I'll test that one this evening and see if I can't correct it. Thanks for all the tips...hopefully I can correct the leaks and not have to toss the holders since 5x7 holders aren't easy to come by.
     
  8. DKT

    DKT Member

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    You could try to take the suspect holder and use gaffer tape to hold it in place? This might help diagnose a leak at that point? We had an Omega 45D that would cause these streaks of light (density) on the neg that for a long time we thought was an agitation mark. Turned out that it was this teeny-weeny pinhole and sometimes it would be there & sometimes not depending on how the bellows was flexed. We had to get a new bellows for that Omega, but in the interim, we still used it by wrapping a darkcloth around the mid-section (bellows) and clamping it tight. It was a PIA to work with everyday, but it kept the film from being fogged. Could be you could do some tests like this, and try to rule out the bellows. The other test might be to take black gaffer's tape and tape the hell out of that holder--get it in place, pull the slide--darken the room--and pop a strobe into it at different angles a couple of times. Then run the film...

    Could also be a developing error.... These things are really hard to track down and will almost drive you nuts....

    KT
     
  9. Silverpixels5

    Silverpixels5 Member

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    Ok i'm pretty convinced that the leaks are from the way the holder sits in the camera. I just developed another negative from a different holder and it has the same patter if light leaks at the top of the image. While it could be the bellows, i doubt it b/c they are brand new, and they seem to be correctly attached to the back end of the camera. Next time I use them I'm just going to keep the darkcloth covered over the back end when I take out the darkslide. Hopefully this will solve my problems.
     
  10. glbeas

    glbeas Member

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    Have you check to see if the camera itself is not warped in some strange way so the holder does not seat right? Or that the 5x7 is made for a standard filmholder? I've heard of some off brands not fitting right.
     
  11. DKT

    DKT Member

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    It could just be the camera back worn down from use. There's an old Kodak studio camera in our collection like this...it's pretty obvious, there are grooves under the spring back from holders being slid in & out from years of use. I've never seen anything like it--the camera was in use in a portrait studio for almost 50 yrs. They shot thousands of negatives on it and literlly wore it out. It wouldn't take much for a holder not to sit right though...
     
  12. Silverpixels5

    Silverpixels5 Member

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    Well I'm going to get a couple new holders to see if its just the wooden Kodak ones that don't fit right. There is no obvious warpage on the camera back where the holder would sit, but then the leak isn't profound either...just apparent. When I was doing the test with the flashlight and hit the right spot, a little light would show through. Then when I adjusted the holder and did the light test again, there was no leak. So I'm pretty sure its dependent on how it's sitting in there. Whethere thats due to the brand or holder or slight warpage in the camera back, I don't know. Time and further tests will tell.
     
  13. glbeas

    glbeas Member

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    How is the spring tesion on the back? From what you describe it may be a little low.
     
  14. Silverpixels5

    Silverpixels5 Member

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    The spring is actually good...but I imagine I can try to make it tighter. The holder seems to be pushed fairly well against the back of the camera when its in there.
     
  15. lee

    lee Member

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    Have you checked the film holders to make sure they are not warpped? I have seen lots of the old wooden ones that are not square anymore. That will cause the holder not to sit snuggly into the slot on the back of the camera.

    lee\c
     
  16. glbeas

    glbeas Member

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    Yeah, too tight and you'll warp the camera putting film in.
    Maybe it's some kind of subtle wear on the back where the film seats allowing the slide to wallow a bit around the proper position. I couldn't really say much without a close look at the camera myself. Have you held a steel rule across the surfaces to check for flatness or some other technique that may apply? If the channel the darkslide goes into has the sides worn away they might possibly be shimmed back to the proper shape.
    Hope you can get it fixed soon, I'm familiar with that frustration with balky gear.
     
  17. Silverpixels5

    Silverpixels5 Member

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    I havn't tried putting a straight edge up to it yet, but I'll do that once I get home. I really like this camera, and it may soon become my favorite if I can get these dag on light leaks taken care of.
     
  18. Silverpixels5

    Silverpixels5 Member

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    Shot four negs today using two of the holders i had problems with, except this time i kept the darkcloth over the camera back when I pulled the slide out and took the picture....no leaks! :smile:

    I'll still have to investigate what the problem was and fix it for good, but until then, this is an adequate solution.