Pentax 67 light leak?
I've been testing a Pentax 67 kit. I'm very much enjoying the lens selection that came with it, mostly wide angles, which I don't usually get to play with.
Problem is, there is a consistent defect in the negatives I'm processing. About 9mm from the right hand side of the neg there is a thin white line. It prints as black. It's on every neg, on multiple rolls. You can see it on the following photo:
Any guesses as to what it is, and how the problem can be addressed?
That line looks to me like you have dust in the calibration area of a flat bed scanner. Are you observing this on the negs with a loupe, or just on scans? It can't be a light leak they look nothing like that, and it would be white on the print.
Looks like something in your developing tank is scratching the negative. When that happens, the scratch is clear, and it prints black. It's such a straight and thin line that I can't think of anything else it might be, particularly as it is consistent with other developed rolls of film. It won't show up in the rebate, of course since the rebate between negs is clear, but if it traverses the whole roll, it's a scratch for sure. What tank do you use?
Toby: it's not dust on the scanner; I'm scanning 8"x10" prints. I can see it on the neg under a loupe, and on the baseboard while enlarging.
John: I don't think it's something scratching during the development. The reason I say this is the mark is running up and down the "6" part of a 6x7 neg - it's not running down the length of the roll. Does that make sense? I process a lot of 120 film, normally shot on my Rolleiflex TLR. I use Patterson tanks and reels. The mark is on every one of the four rolls I've shot on the camera - the negs were processed at different times.
Doesn't look like a light leak. I'd suspect shutter bounce, but that's just a guess. Does it happen on every speed, or just the highest speeds?.
Most of the time that I've been using this camera, I've been using it at night with 'B' setting - with the mirror locked up. When I'm in the darkroom next I'll look at some negs that were not shot at night and see if the issue is still there.
Can't be a light leak if it prints black, but I can't think what might cause this. Perhaps something physically in the way, thread or hair? Guessing here.
You're right - it can't be a light leak. Sometimes it's hard to wrap ones head around the problem!
Your idea about it being a thread or hair was a good one. I put the camera up on a tripod, put the mirror up and put the shutter on bulb. I used a flashlight and looked very carefully but could find nothing.
It's a shame, as the camera itself is in wonderful shape and the lenses are immaculate. It might remain a mystery!
On every frame of every roll?
Yes, it's on every frame on every roll. It is very faint, mind you, and is essentially hidden if there is detail in the image where the line is. If there is sky, like the image in the initial post, it is very evident.