Unreasonable test of bellow light-tightness?

[Steve Goldstein]

The bellows on one of my cameras was taped by the previous owner to repair some light leaks. It's a good taping job, actually, very neatly done and seemingly effective in my experience. Yesterday I was doing stuff around the house so I set the camera up in bright roomlight (not direct sunlight), loaded a holder with a sheet of TMY-2, pulled the darkslide, and let is sit that way for an hour. The only protective measures I took were to shield the dark-slide opening in the holder and to leave both caps on the lens. The film came out uniformly light grey, guessing maybe 0.3 by comparison with a 0.45 center filter. Developer was HC-110, Dilution B, time per F-4043.

Was my test excessive? How many of you guys leave a camera set up with the slide pulled for this length of time during the day?

Now I'm wondering if I should replace the bellows...

[Bob Salomon]

First, you don't need to shade the slot. You just learn how far to pull the slide out so the film is fully uncovered and the slide is still in the slot. Draw a line on that point so you always know how far to withdraw the slide.
Next, you need to find out what the minimum amount of time is for your camera to develop base fog. It shouldn't at any length of time.

[jp]

Can you see the shadows of the film holder edges You could pull the darkslide half way and see how light interferes with that obstacle to get an idea of where light is coming in.

[Steve Goldstein]

I can see clear film rebate all the way around.

[Jim Noel]

The bellows on one of my cameras was taped by the previous owner to repair some light leaks. It's a good taping job, actually, very neatly done and seemingly effective in my experience. Yesterday I was doing stuff around the house so I set the camera up in bright roomlight (not direct sunlight), loaded a holder with a sheet of TMY-2, pulled the darkslide, and let is sit that way for an hour. The only protective measures I took were to shield the dark-slide opening in the holder and to leave both caps on the lens. The film came out uniformly light grey, guessing maybe 0.3 by comparison with a 0.45 center filter. Developer was HC-110, Dilution B, time per F-4043.

Was my test excessive? How many of you guys leave a camera set up with the slide pulled for this length of time during the day?

Now I'm wondering if I should replace the bellows...

Short answer - YES.

[Ted R]

In my opinion that was an unreasonable test.

But if you are the obsessive type :-) before replacing the bellows make a careful check of the light-tightness of the joint between the back and the camera body and between the lens panel and the camera body, don't assume the leakage is in the bellows it may be elsewhere.

[Jim Jones]

Lens caps are more for lens protection than for completely blocking the full spectrum of light. This test may be more informative with metal lens caps or a blank metal lens board.

[Bob Salomon]

In my opinion that was an unreasonable test.

But if you are the obsessive type :-) before replacing the bellows make a careful check of the light-tightness of the joint between the back and the camera body and between the lens panel and the camera body, don't assume the leakage is in the bellows it may be elsewhere.

Or it could be a problem with where the bellows attaches to the camera.

[Steve Goldstein]

Jim, the caps were on the lens more to protect it against me than to block the light - the shutter was closed.

The flashlight test hasn't shown any light leaks yet, but now that you guys mention it, I didn't test where the bellows attaches to the standards, or where the back mounts. Into the darkroom tonight!

[tgtaylor]

My guess is that the bellows is not UV tight.

Thomas