Recurrent black smearing / streaking on last frames of Kodak 35 mm films (since ~2020)

[Lachlan Young]

@Joerg Bergs . Can you explain your workflow, please?

• How you extract the film from the cassette for processing?
• Are the films processed by hand or machine?
• What type of machine?
• Do you use twinchecks to match film to docket/order pouch?
• What type (if any) of film clips do the lab use, for hanging negative strip prior to scan/print?

And the other question for @Joerg Bergs is: how many people are doing the loading, and is it all happening on one site?

With an awful lot of these intermittent faults, while there might have been small manufacturing changes (e.g. to plasticiser or gelatin extenders) that make the emulsions fractionally more sensitive to physical mishandling in some specific lab environments, I do also wonder if a significant percentage also relates to people advancing the film until it's taught at the end of the roll, then on rewinding it somehow ends up getting wound back into the cartridge the opposite way out - on thinking further about it, this was the one time I saw the fault (or something similar) to the one described.

And while all 135 Kodak colour is now on Estar, the B&W is (as far as I can tell) still on CTA - the bases are quite readily identifiable by handling characteristics on loading to reels.

 

[Joerg Bergs]

I have already described the equipment we use. The film shown here was exposed with a Leica M6, so there was no fast-forwarding followed by exposure. The Kodak black-and-white film used is also coated on Estar base.

We label films with double numbers, but this is unrelated to the issue described, as the problem occurs at the end of the film, not at the beginning.

I do not know which cameras our customers use. For scanning there is no need to clip the film. We use only clips for the dip&dunk, but not for the other machines.