Fogged film

Discussion in 'Large Format' started by z_z|1, Jul 25, 2002.

  1. I have just gotten a bunch of film processed and several of the negs
    where fogged. Must have happened in the camera as the edges were
    still clear as they should be.

    On some of the pics I took I had put the film holder in the camera
    and pulled the slide. Then I waited for the light to get right.
    This could have taken several minutes. The exposures where around
    1/15th of a second so not excessively long. On the neg, you could
    still see the image, but fogged. This happened with both B&W and
    color.

    Sucks, it took me hours of heavy hiking up a mountain to get to the
    spot I wanted. Fortunately not every picture was fogged so got
    something out of it.

    My question is do you normally leave the dark slide out when you are
    waiting for the light, or just pull it out before you take the
    pciture?

    Eric
     
  2. I leave th slids in. Check your bellows; you may have a pinhole leak.
     
  3. I'm not an expert (only been shooting LF for 4 months) but most likely to be light leaking in through bellows.
    As you are getting sharp edges probably not the holders. But make sure the holders are numbered and the number of the holder goes on your notes so then its possible to track any faults back to a holder.
    I always remove the DS as soon as I'm set up and while I'm waiting for the right moment. On one occasion (and only once) I removed the DS and waited for three minutes and at the crucial moment could not fire the shutter - I had left the iris open all that time while waiting and, heh presto, a tranny with nearly no detail on it.
    Hope this helps but might get better advice from the many more experienced LFers here.
     
  4. I pull the dark slide and then immediately cover the holder with the dark cloth every time I make a photograph. However, if the whole image area was fogged, I'd guess as others have said that it's a bellows leak. In my (unfortunate) experience, when light enters the holder as a result of the dark slide being pulled the result was diagonal streaks, not a uniform fogging of the entire image area. I suppose though that could vary depending on the direction of the light. You can check for bellows leaks by opening the camera in a dark room and shining a flash light inside the bellows while you observe from the outside.
     
  5. Eric- I had a similar problem not long ago. Though I wasn't
    waiting too long for the shot to happen. I checked my bellows
    and found no holes, the holders seated nicely and all. So, I was
    stumped until I removed the new lens I had just mounted. I had
    neglected to paint the INSIDE of the lensboard flat black.
    Apparently, the film bounces light back to the board and it
    reflected non image light back to the film, creating some fog.
    Painted the board, Voila, problem solved. Hope this helps
    Gary
     
  6. Eric, you might also want to check your lensboard for small holes. I had this happen to me with a wooden lenboard. It appeared that another lens had been mounted on the board and all of the original holes had not been plugged. To discover this, I took the camera into the darkroom in total darkness used a small flashlight and projected the beam around the bellows while looking into the film end of the camera with groundglass removed. Originally I suspected a bellows leak, not finding one I shined the light onto the lens and there it was, a small hole allowing light to enter. Ed
     
  7. Eric, since every neg. is not fogged, I would suspect leaking light traps on some of your filmholders. If the fog was caused by a bellows or lensboard pinhole, you would probably see some degree of fogging on all of the films. Most light traps on filmholders will leak when exposed to strong direct sunlight over a length of time. Cover the slot with a darkcloth or opaque object while pulling the slide, and keep it covered until replacing the slide. The material in the traps becomes compressed over time and the slots are no longer light tight when the slide is pulled. If a filmholder leaks, it is usually impractical or impossible to repair it.
     
  8. Thanks everyone for the excellent tips and suggestions. I will investigate each one of them. Since I don't precess my own film I guess to identify the film holders I would have to notch them so I could match negs to holders. Is that what most of you do?

    Eric
     
  9. if you are just going to run some test shots, then you can just put a numbered card or chalkboard in each shot and not the number on the holder

    Of course if the fogging is so bad you couldn't read the number...

    tim
     
  10. As you don't process yourself put the check of the film holders as the last thing to do. If you have access to a Polaroid film holder, that will save you a lot of time and probably money too. Else, rent one. As you don't process yourself, the cost of the polaroids will probably be less than the developing costs and you will have ruled out everything except the possibility of leaking film holders within the hour.<br>
    The most probable thing is a leaky or pinholed bellows and you can easily start up with checking for that. All it takes is that you, in a darkish room, put a flashlight/electric torch inside the camera and extend the bellows. You will quite easily see if and where there is a leak.
     
  11. I once made the mistake of pulling a metal filmholder out of a plastic bag in the dark cupboard. A tiny bit of static electricity light occured, barely enough to see - I loaded the film anyway and 2 sheets were faintly fogged on development on one side.
     
  12. Another possibility. I had a similar situation once that appeared to be fogged film like you described. The film edges were clear, but the image area was so dense that it appeared to have been fogged evenly over the entire neg. However, I eventually found that the problem was grossly extreme overexposure caused by a faulty shutter. When I would close the old Graphex shutter, the blades would not always close completely, leaving a very small shutter opening. If I exposed immediately after pullling the dark slide, there was no problem. But, if I waited some time before tripping the shutter, there would be an extreme amount of additional exposure because of the bad shutter. You didn't mention the lens and shutter you are using, so you might want to check them out also.
     
  13. I am using a Rodenstock 150mm Geronar. It appears to be working fine. I also took the camera, sans lens in to the darkroom and shone a light into the front end. I couldn't detect any pinhole light leaks. It's a mystery! I will be out again tomorrow and will try again. Just in case I bought some new film holders to see if that makes a difference. I'll let you know.

    Eric
     

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