What did I do wrong on these B&W negatives?

[adelorenzo]

I just processed another roll from that camera and same problem. Instead of being 3-4 frames at the end of the roll this time it was 5-6 frames in the middle of the roll. It was a bone dry reel and everything seemed fine loading it and when it was coming out of the tank. I really don't think there is a problem with the processing, I've done enough rolls to know when I've screwed something up.

Since the sides of the negatives are dark this is leading me to believe it is a camera issue and the film is not getting light somehow. Would it be possible that I have film problem? Maybe the film is curling and so the top and bottom edges are not getting exposed? I was shooting at -30 C and the camera was very cold so I am wondering if this is causing some kind of problem in the camera.

I'm going to try shooting a test roll indoors to see if cold is a factor, and also will try a different film back to see if that is part of the problem. Maybe my pressure plate isn't working in the cold?

Here are some more scans, as always any thoughts and feedback welcome.

[MattKing]

Was this shot using a Pentax 645NII? If not, what type of camera?

[MARKNABIA]

looks like the curling is pretty consistent on each frame.try to send your next film to the lab, then if it the same problem, you might wanna check your camera...

[adelorenzo]

Yes, it's with my 645NII.

I have had recent rolls out of this camera processed by a lab and at home without this problem. So either it has happened very recently or it's somehow related to the cold weather. If I can shoot a test roll indoors without a problem then maybe I can narrow it down to temperature.

[Bob-D659]

Well looking at the first new frame you posted, it almost looks like light is coming around the bump on the lower right side. Check the camera, something could be buckling in front of the shutter curtains and causing a shadow on the film, maybe?

[johnielvis]

well--are you rolling the film on the reel so the emulsion is facing toward the center of the reel (with the wind of the roll) or so the eumulsion faces away from the center (against the wind on the film spool)?

if outside, then maybe the "spring action"is causing the film to press against the reel more tightly--if so, try winding emulsing side in.

well...actually this is sounding more and more like it's the film...I just noticed that it is not kodak film....I've had wierd problems with non-kodak films in the past...
you may have a bad batch of film.

well...it's not that bad--just shoot with a slight bigger border and one day the source of the problem will become apparent and you'll let us all know. This little bit of artsy extra border isn't worth snifflng about and may become fashionable---I say EXPLOIT it...print with the weird border and take full credit for discovering a new way of hipsterizing a pic...even though you don't know what causes it, you know how to get it...use your camera with your film and your normal dev process...nobody else can duplicate it!!!!

[adelorenzo]

This is on Pan F+ but the last roll was Delta 400 so I'm reasonably confident it's not a film issue. I've had good rolls out of both of these batches of film.

I did have some unexpected vignetting on a few shots. I'll open the camera and lens and see if anything looks weird.

[adelorenzo]

I shot a film test with Tri-X tonight. All the frames came out just fine, using my normal agitation and development style. I really don't think this could be a development problem, especially since the frames with these problems have clear edges.

So that means it is looking like a camera or a lens issue and possibly cold related. I opened the back and cycled the shutter and don't see any problems. Ditto with the lens, everything appears normal. I'll inspect the film back a little closer and compare it to the other ones that I own.

I just can't think of how light could be getting blocked from the sides of the frames, which is the top and bottom of the film in the camera. Is my film buckling in the cold?

[Bob-D659]

Well I just had a look in my 645, the original one, the light absorbing liner behind the mirror and in front of the shutter appears to be a flock covered plastic liner. It could come loose, I guess and buckle and bow out on the sides, in front of the frame rails. If you can lock your shutter open on a B or T setting it's easier to look at. You do have to push in on one of the pins on the grip side of the camera to fool it into working without a film insert.

Those "marks" are on the sides of the frame and the camera, not the top and bottom.

[Rafal Lukawiecki]

Would it be possible that you stored the film next to a chemical for quite some time that would desensitise the emulsion at the edges of the the first few frames? A bit like a fat roll light leak but vapour, not light. I realise this is a long shot, but long term storage next to Ferricyanide etc? Or, frozen storage with humidity, ice forming, backing paper sticking... Brain storming.

It is puzzling how regular the top and bottom is. I suppose mechanical issue is more likely, in the camera.

Ps. I did not realise it is between frames, was thinking top and bottom. Ignore my suggestion, please.