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Thread: What's causing this fogging in my film?

  1. #1

    What's causing this fogging in my film?

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    Is this bad tape on my holders? See it on enough of my negs recently to be an annoyance. the film went through airport carry on X-ray 3 times and was in DHL and customs hands for 3 weeks for additional good measure.

    Couldn't be a light leak in my changing bag right? I always try and drape the darkcloth around the camera back as soon as I pull the slide, but as we all know sometimes that's akin to 'hoisting the mainsail' and isn't feasible in certain weather conditions. The film was fresh, from Keith Canham.

  2. #2

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    Re: What's causing this fogging in my film?

    If this is happening on the flap end of the film, try using a black marker to blacken the flap and the area into which it closes.
    If it is on the slot end, NEVER LET YOUR HOLDERS BE EXPOSED TO THE SUN. You say you put the dark cloth around the back AS SOON AS you pull the slide. This could be too late. How large is your darkcloth? I assume you are using a 4x5 camera, if so,you need a dark cloth at least 4x5 feet, smaller will often be inadequate.
    I learned from Cole Weston to use a cloth large enough to drape over your holder box and transfer the cloth and film holder to the camera at the same time. The easy way is to keep the film between the tripod legs and dark cloth over the camera. Then with a large enough cloth there is never a problem with light streaks through the holder, the back of the camera or the bellows.

  3. #3
    Vaughn's Avatar
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    Re: What's causing this fogging in my film?

    It happen while film was in the holders -- probably in-camera. It is rare for light to leak past the light traps of the flap, even with no tape, let alone damaged tape...and the fog pattern does not indicate that.

    It possibly could be from pulling the darkslide slightly towards you while removing it before the exposure. Easy to do standing in tight high places!

    If it is a very common problem (many negs from different holders), then I would suggest it is a light leak within your camera system. Do the flashlight test of the bellows, camera back, and lensboards. It is always good to do one before a big trip, not that I do it often enough (I lost three months of 4x5 images of New Zealand due to light sneaking in thru a big gap between the body of the camera and the film back.) Also check for shiny surfaces within the camera.
    "Landscapes exist in the material world yet soar in the realms of the spirit..." Tsung Ping, 5th Century China

  4. #4

    Re: What's causing this fogging in my film?

    Quote Originally Posted by Jim Noel View Post
    If this is happening on the flap end of the film, try using a black marker to blacken the flap and the area into which it closes.
    If it is on the slot end, NEVER LET YOUR HOLDERS BE EXPOSED TO THE SUN. You say you put the dark cloth around the back AS SOON AS you pull the slide. This could be too late. How large is your darkcloth? I assume you are using a 4x5 camera, if so,you need a dark cloth at least 4x5 feet, smaller will often be inadequate.
    I learned from Cole Weston to use a cloth large enough to drape over your holder box and transfer the cloth and film holder to the camera at the same time. The easy way is to keep the film between the tripod legs and dark cloth over the camera. Then with a large enough cloth there is never a problem with light streaks through the holder, the back of the camera or the bellows.
    Thanks Jim, it's a 5x7 Deardorff special. I have one of those BTZS dark cloths specifically designed for 5x7 with a closed elastic "tube" on one end. Maybe it's time to retire it, as the design of it doesn't really allow me to insert a holder while it's draped around the camera back, it's hard to explain without showing you. It is smaller than a normal black fabric one.

    I'm getting the fog on both of the short sides. The tape looks strong on all the holders and they are already black fidelity elites which look to be in good shape. But perhaps you are right about the cloth...although with wind and rain it gets tricky to employ the technique you describe.

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  5. #5

    Re: What's causing this fogging in my film?

    Quote Originally Posted by Vaughn View Post
    It happen while film was in the holders -- probably in-camera. It is rare for light to leak past the light traps of the flap, even with no tape, let alone damaged tape.

    It possibly could be from pulling the darkslide slightly towards you while removing it before the shot.

    If it is a very common problem (many negs from different holders), then I would suggest it is a light leak within your camera system. Do the flashlight test of the bellows, camera back, and lensboards. It is always good to do one before a big trip, not that I do it often enough (I lost three months of 4x5 images of New Zealand due to light sneaking in thru a big gap between the body of the camera and the film back.) Also check for shiny surfaces within the camera.
    Thanks Vaughn, I would hope after doing this for 20 years that it is not from pulling the slide toward me while removing, but perhaps I am getting rusty. I did do the flashlight test before I left and will do it again now. I'm also using a 150 rodenstock W lens on everything, which has a huge image circle - don't know if that could also be a contributing factor?

  6. #6
    Vaughn's Avatar
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    Re: What's causing this fogging in my film?

    You got the most fogging on the corners of the hinge-end when you had the most light hitting those corners from the lens -- so internal flare with that extra light coming in with that wide-coverage lens might be be an issue. A lens shade that cuts off some that extra might help when using it. Bright foggy days will produce the most flare (other than pointing the lens towards the sun.) Relatively bright light (relative to the total exposure) is coming into the lens from all directions.

    After 45 years of LF work, I still think about pulling the slide out straight -- especially hanging off cliffs, etc! An old 5x7 with weak springs also reminds me. I squeeze the film back and the camera body together while I take the slide out on all cameras whenever possible. 11x14 darkslides can be very interesting to remove at times!

    The reason I suspected it in your case is that often the light shoots across the holder and fogs the opposite end also.

    The light leak test should show you any problems with the holder hinges, also. Remove the darkslide of the suspected holder when you use it for the test and get that flashlight tight into the corner and pointed into the corner.
    "Landscapes exist in the material world yet soar in the realms of the spirit..." Tsung Ping, 5th Century China

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    Re: What's causing this fogging in my film?

    I agree with Vaughn. AS for a dark cloth the one I use for 5x7, is 5x8 feet. I also use it for 8x10, 5x12 and 7x17. The best purchase I ever made. It is too bad the young man who was making them was forced out of business. It is black and slick cloth on the inside, and white somewhat rain repellent on the outside.

  8. #8
    Cor's Avatar
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    Re: What's causing this fogging in my film?

    I had a similair inconsistent problem with my Toyo Field 810M, which I finally traced down to a tiny gap between my bellows and the back frame were the groundglass and filmholder sits. Very difficult to see even with a strong flash light shining inside the bellows in my darkroom. Apperantly this tiny tiny gap was enough to cause this fogging. Perhaps understandable when you sometimes wait for the right moment after removing the darkslide, as well as the angle of the sun towards said gap.

    Good luck,

    Cor

  9. #9
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    Re: What's causing this fogging in my film?

    Looks like mist from the water.

  10. #10

    Re: What's causing this fogging in my film?

    Quote Originally Posted by Cor View Post
    I had a similair inconsistent problem with my Toyo Field 810M, which I finally traced down to a tiny gap between my bellows and the back frame were the groundglass and filmholder sits. Very difficult to see even with a strong flash light shining inside the bellows in my darkroom. Apperantly this tiny tiny gap was enough to cause this fogging. Perhaps understandable when you sometimes wait for the right moment after removing the darkslide, as well as the angle of the sun towards said gap.

    Good luck,

    Cor
    Thanks – Yeah that's what I suspicious it might be. (at least some of the time) I do think there might be a correspondence between yanking the slide and waiting for the wind to die down and the ones that show it. I need to get a better flashlight and try the bellows from the inside. I've just been using my iphone flashlight from the outside, can't see any leakage that way.

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