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David Lobato
3-Jun-2016, 12:14
I have an 11x14 Empire State Camera No. 1 with light leaks on most of the negatives. The camera is wood, about 100 years old and in fine condition. After a bit of investigation with removing the back and inserting film holders I found the source of the leaks. Light enters through very thin gaps between the plane of the film holder and the wooden back under the ground glass frame. The light traps in the wooden back are ineffective at blocking light coming around the right angle inside corners on the periphery of the film holder. This is evidenced with a flashlight on the outside frame edge and looking at the inside film plane. This matches with the light streaks and fog patterns on the negatives.

My idea is to stick strips of black felt on the back all around the edge under where the film holder is located. This might seal the thin gaps where light leaks in. The added small distance from the lens should be negated because the ground glass frame will rest on the same felt lined plane as the film holder. Painting the inside light trap surfaces black would also help if the felt does not completely solve the leaks.

Does anyone have experience fixing light leaks with strips of felt? Any recommendations on felt material?

Bruce Schultz
3-Jun-2016, 12:31
I've had a similar problem with a Century 11x14 when the back is positioned in the vertical mode. I always make sure the spring is pushing down on the holder adequately and I also keep the back covered with the dark cloth, even when removing the dark slide. Of course, that's a challenge when the tripod is extended to eye level.
Your felt idea sounds like it's worth a try since it can be done without permanently altering the camera. Any effect on the 'T' measurement for the film plane should have an equal effect on the ground glass.

Randy Moe
3-Jun-2016, 13:33
Use this all the time. It is not black, but brown.

Being poly is sheds very little if any.

http://www.amazon.com/JVCC-FELT-06-Polyester-Felt-Tape/dp/B01455QMX4/ref=sr_1_7?ie=UTF8&qid=1464985904&sr=8-7&keywords=felt+with+adhesive+backing

Greg
3-Jun-2016, 14:19
Also check that the back is not warped. I had an 11x14 Improved Empire State that had a similar light leak. Tried a material similar to felt but the leak was still there. Finally took the back a bit apart and it wouldn't lie flat on a sheet of thick glass. Fixed it but can't remember how... that was probably 35 years ago. But I do remember how the camera was very light and very compact.

Steven Tribe
4-Jun-2016, 01:03
Velvet is a better solution than felt, as it gives a better light seal with varying compression on the material. Available in non fraying widths.

RichardRitter
4-Jun-2016, 02:29
Check the depth of the lock rib glove to the height of the lock rid on the holder.

David Lobato
4-Jun-2016, 15:06
Thanks for the tips everyone, much appreciated. I'll check on both felt and velvet strips. And will cover the back with a dark cloth for insurance. It took only a tiny bit of daylight to fog the film.

I did check for warpage of the back's wooden frame. It was very slight, better than expected for the camera's age.

Richard, the back has no channel for a film holder's locking rib. There is a wood strip that stops the hinged bottom of a film holder just short of the holder's rib touching the camera back. The overall dimension of the back is too small to add a groove.