Straight Line Light Leak on Verticals

[G Benaim]

Hi all,

I've gotten a new to me light leak, was hoping you could help me diagnose it. It's a straight thin line of higher density one the darkslide side when shooting verticals, so it's an 8 inch line just inside the edge of the exposed area. This has happened only w my plastic holders so far, and I use both wood and plastic. When shooting verticals, I insert the holder such that I pull the darkslide down, not up, leaving the baffle less exposed to direct light. I use a Master view, fwiw. Have at it, light leak experts!

GB

[Louie Powell]

Let me make sure that the problem is clearly stated: you are getting fogging along the darkslide. This occurs ONLY when you are shooting verticals, but you routinely (ALWAYS) orient the camera back so that the darkslide end of the holder is down.

Is that a correct statement of the problem?

Does this problem occur with only one holder, or have you noticed it will most or all of your holders?

Occam's Razor suggests looking for the simplest possible solution. I could suggest that the light trap in your holder(s) is opening when the darkslide is withdrawn due to the effect of gravity, but that is unlikely to affect all of your holders, and it's a stretch even then.

Is it possible that you are inadvertently lifting the film holder away from the camera back when you reinsert the holder following an exposure? That would tend to fog the end of the film near the opening where the darkslide goes in.

I know that in my case, when I orient the camera back so that the darkslide pulls down, the back of the tripod is in the way and it is necessary to bend the darkslide in order to get it out of the filmholder. If that's the case, the process of reinserting it could easily pull the back away from the camera and lead to fogging.

[G Benaim]

Hi, Louie,

I've noticed it on several holders, and I too was thinking it has to do w the angle of insertion of the slide. I'll try it w the slide pointing up just to see.

[Gene McCluney]

One should always grip camera and ground glass and exert pressure to "squeeze" them together against the holder, while removing or inserting darkslides, thus helping to prevent the darkslide pull from leveraging the holder away from the camera causing a leak.

Some holders have very "stiff" darkslides that have a lot of friction, so you have to pull rather hard. To correct this just wax both sides of the darkslide with good old Johnsons Paste Wax (available in the floor care section of supermarket). Apply a light coat completely across the face of both slides of dark slide, then buff with a soft cloth. Amazing how much easier the darkslides slide in and out. This will in no way do any harm to the dark slide or the film.

I think you are slightly pulling the film holder away from the camera, even if it doesn't seem like you are. The above 2 techniques will help.

[G Benaim]

Thanks Gene, I'll try squeezing the back. The slides on the plastic holders are too loose, if anything, not too tight.

GB

[Brian Ellis]

If you're concerned about light getting into the holders when you shoot verticals, you might try just laying your dark cloth across the top of the holder after the dark slide is pulled instead of turning the camera back upside down. That's what I did (using a BTZS dark cloth, which is smaller and lighter than a typical "horse blanket") after I got a few leaks shooting verticals and never had a problem again.

[Ole Tjugen]

I had something similar at one time, and finally traced it back to a missing felt strip along one side of the camera back. This allowed a tiny amount of light to leak in - but since that side was on the bottom in landscape orientation (pulling the dark slide out to the right), it wasn't obvoius in those cases. On verticals it was along the side and thus saw a lot more light leaking in...