Exposure, Light Leak or Darkroom Issues?

[mjandreo]

Hello,

I'm new here and new to large format photography. I have a Zone VI camera (bail back). I'm processing myself using the Stearman Press SP-445 and Ilford chemicals (shot on 4x5 ilford fp4+). For some reason the bottom 1/5 of my negatives seems to expose correctly or darker where as the rest of the negative is overexposed and more blurry.

Any idea of what's going on here? Any help appreciated - thanks!

Marc
images below - first 2 images are scans of the bw photos, second 2 are negatives

[mpirie]

Looks like a light leak in either the film holder or in the back.

Mike

[stefn]

Agreed, light leak somewhere. Did you use the same film holder for all shots? If so, it's probably the holder, if not then it could be the camera back. Make sure the holder is seated correctly before pulling the darkslide. Assuming that is the case, one possible fix is to drape your dark cloth over the camera back & holder once you're set up to shoot, although further investigation is warranted.

[Louie Powell]

You problem may be that as you are pulling the darkslide, you are also inadvertently and unknowingly lifting the holder away from the back of the camera. This allows light to get inside the camera to fog the film, and occurs because the handle on the darkslide is short which means that it is difficult to grip. This is a known issue with bail-type backs. If this is the problem, the fogging will always occur across the short dimension of the negative and on the end of the holder away from the darkslide opening.

I also have a Zone VI and had a similar issue years ago when using a model 405 polaroid back. My problem was that when drawing the darkslide, I was inadvertently lifting the polaroid holder away from the back of the camera, allowing light to get inside the back and fog the portion of the film that was revealed as the slide was being withdrawn. The root cause was that my fat fingers could not fit under the handle to pull it out without also lifting the back away from the camera.

The solution involved a combination of things. As stefn suggested, I adopted the practice of draping the darkcloth over the camera when drawing the darkslide. Also, I used a coin as a lever when initially pulling the darkslide - using a coin meant that I was pressing the holder against the back rather than trying to pull it away. Once the darkslide was partially withdrawn, it was flexible enough to allow my fingers to fit under it to pull it the rest of the way without pulling the holder away from the camera. Finally, the ultimate solution was that I used up my remaining stock of polaroid film, and since it was no longer being made in that size, I could no longer use that 405 back.

[mjandreo]

Thanks for your answers! So I did have a dark cloth over the back when inserting/re-inserting the dark slide. When re-inserting the dark slide I have noticed that it often doesn't go in totally smoothly - it will take probably 3-5 seconds for me to get it back in...is that normal? Will that cause the over-exposure of 4/5 of the negative as seen above?

Also I just tested reinserting dark slides with a flash light in the bellows and it seems like the bail back is very secure and no light leaks out when I pull out or re-insert the dark slide.

I also did a flashlight test last night and noticed that my lens board wasn't completely light tight. Could that cause the 4/5 of the negative to be over-exposed?

Thanks for any info!

[Keith Fleming]

I also have a Zone VI camera, and years ago I had problems with light leaks. I sent it to Richard Ritter (www.lg4mat.net) for calibration. He fixed the problem, and calibrated the camera--including ensuring the ground glass wat at the right distance for proper focusing.

Wood cameras, after all, are made of wood. Time, use, humidity, etc. can cause wooden cameras to need repair and calibration.

I should add that Richard was involved in the actual manufacture of Zone VI cameras and the Zone VI modifications to Pentax light meters.

Keith

[Huub]

Thanks for your answers! So I did have a dark cloth over the back when inserting/re-inserting the dark slide. When re-inserting the dark slide I have noticed that it often doesn't go in totally smoothly - it will take probably 3-5 seconds for me to get it back in...is that normal? Will that cause the over-exposure of 4/5 of the negative as seen above?

Because the light leaks look like an even fog along a straight line, they are probably caused when pulling or inserting the darkslide. The part that was covered my the darkslide getting the right exposure, the open part being hit by stray light, causing the fog. Darkslides should slide in and out smoothly without using to much power. Old ones can get a bit sticky, which might be cause of it all. Clean them and then excersize them a few dozen times until the darkslide can be pulled and inserted with ease.

[Gary Beasley]

Thanks for your answers! So I did have a dark cloth over the back when inserting/re-inserting the dark slide. When re-inserting the dark slide I have noticed that it often doesn't go in totally smoothly - it will take probably 3-5 seconds for me to get it back in...is that normal? Will that cause the over-exposure of 4/5 of the negative as seen above?

Also I just tested reinserting dark slides with a flash light in the bellows and it seems like the bail back is very secure and no light leaks out when I pull out or re-insert the dark slide.

I also did a flashlight test last night and noticed that my lens board wasn't completely light tight. Could that cause the 4/5 of the negative to be over-exposed?

Thanks for any info!

You need to fix that light leak at the lens board before doing anything else. Any light leak of any kind will cause serious problems.

[mjandreo]

UPDATE: So I fixed the light leaks at the lens board by placing double black tape over all the leaking areas (and then ordering a new lens board). I also flash light tested (flashlight in bellows) in a dark room and tried pulling out dark slides to determine exactly where the leaks were happening. It turns out that the problem was specific only to the poor-fitting lens board area and not to the film holders or dark slides. Problem solved and all my negs are coming out fine now! thanks for everyone's input.

You need to fix that light leak at the lens board before doing anything else. Any light leak of any kind will cause serious problems.