Yes, I have seen light when removing the tape from 120 film. When I took a medium format film class at a local university, the professor advised us to never peel off the tape because static electricity can produce sparks. However, light contamination would cause dark areas on the developed film, right?as I recall stripping the tape I would see a faint glow from the adhesive could it be the edge of the tape laying on the emulsion?
I have been out of the business for a long time but in the 70s as I recall stripping the tape I would see a faint glow from the adhesive could it be the edge of the tape laying on the emulsion?
could it be the edge of the tape laying on the emulsion?
(Welcome to Photrio!) I'd be surprised if that extended all the way into frame 36; the tape is a little further towards the end of the film. IME the tape on Kodak film doesn't extend very far onto the film strip; an inch or so.
You might just be on to something with that theory. That's the best explanation I've heard so far.I was thinking that if the tape was to allow some of the adhesive to sort of leak out of the end then the first wrap around the spool could get some on it, obviously only on the very last frame 36+.
Checked closer and found a number of Kodak negatives with this problem!
All on BW Kodak films, not a single on Kodak C-41. My C-41 to BW ratio is probably 10:1, so it was easy to miss at first as OP said that all Kodak films are affected equally. In my case I'd expect at least some of C-41 to have this problem. Hmm...
I can't think of a thing that I do differently when handling BW film vs. C-41 that would cause this.
I don't follow to be honest. It's officially a 36 exp. film. Many cameras like most of the EOS series will expose exactly 36 frames on a nominal 36 exp roll. Most film over the past decades has performed fine that way from the first frame to the last; there's already a safety margin in both the leader and trailer ends of the film. I don't see how it's reasonable to accommodate for what now starts to look like a manufacturing defect by rewinding early.35 exposures on a roll is considerably more sane and convenient.
I don't follow to be honest. It's officially a 36 exp. film. Many cameras like most of the EOS series will expose exactly 36 frames on a nominal 36 exp roll. Most film over the past decades has performed fine that way from the first frame to the last; there's already a safety margin in both the leader and trailer ends of the film. I don't see how it's reasonable to accommodate for what now starts to look like a manufacturing defect by rewinding early.
Let's call a spade a spade - it's a defect and it's not supposed to be there, regardless if it's frame 36, 1 or 18.
7 strips of 5 fit on 8x10 much more comfortably than 36
The defect as shown is firmly WITHIN frame 36 as indicated by the manufacturer's edge imprint and thus within the area of the film officially intended for image-making.A 'defect' out by the tape and beyond the end of frame 36 isn't a defect
The book predates the recent expansion of confectioning at Eastman Kodak and thus it's not certain that the presently used equipment works the same as the equipment shown in the book. It's entirely plausible that a new conceptual design will involve new failure modes.The machine that does the cutting/ taping/ staking of the canisters is on pg.290 of Bob Shanebrook's book.
When was your C41 film manufactured? It certainly affects C41 as well and what is even more concerning is I may be starting to see the same issue on 120 too.
It's entirely plausible that a new conceptual design will involve new failure modes.
I understand your point.It's not that hard to understand that OP is looking for input on Kodak film produced at about 2020 and later. And I went and had a look at my films that met that criteria. I couldn't find (yet?) a C-41 roll with the defects I'm seeing on my Kodak BW.
The emulsion defect occurring beyond frame 36 can be observed on all of our processing systems, including hand development — but not on every roll.
I've processed plenty of Kodak 135 film (BW and colour) in the same time period (some even shot to the end of the roll) and not seen the same defects, even on Tmax 3200 which can be pretty sensitive (I've seen others, including canister lip tensioning problems on Kentmere 400). However, I am not using an RT machine and always break open the canister for loading reels, so I am not tensioning the end of the film hard. If the length of the film has been shortened even by just a little, systems that rely on that bit of slack at the end of the roll are going to produce problems.
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