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

[Joerg Bergs]

Hello everyone,

I would like to report a recurring issue that I have been observing for several years now and would like to know whether others have seen something similar.

Observation:
On virtually all Kodak 35 mm films I have used since approximately 2020 – color negative and black & white alike – I see dark smearing or streak-like marks on the last frames of the roll, typically frames 37–39.
The marks are always located near the end of the film, i.e. the section that sits closest to the spool core when fully wound.

Key characteristics:

• Appears on almost every Kodak 35 mm film, regardless of emulsion (Portra, Tri-X, T-Max, etc.)
• Always limited to the final frames of the roll on the emulsion side
• The pattern looks like black smearing or streaking, not typical light leaks. There is no silver visible on the emulsion
• Consistent position relative to the film end

What can be ruled out:
This issue is independent of development method.
It occurs with hanger development, dip-and-dunk or transport systems, and in JOBO tanks.
It occurs with different developers, chemistries, agitation styles.

Because of this, it does not appear to be a development or processing artifact.

It is also not camera-specific and appears across different cameras and workflows.

Hypothesis and open questions:
Given that the marks only affect the film end, appear regardless of processing, and are consistent across Kodak 35 mm films, I suspect a mechanical or material-related cause.
Possible factors could include film base or backing layer behavior near the spool core, pressure, friction, or adhesion at the film end, or changes in Kodak’s 35 mm film manufacturing, backing, or attachment to the spool core in recent years.

Questions to the community:

• Has anyone else observed similar marks on recent Kodak 35 mm films?
• Are there known changes in Kodak’s 35 mm cassette, film base, or backing since around 2020?

I am deliberately not drawing conclusions and would appreciate any shared observations or technical insights.

Thank you very much.

 

[koraks]

This is a wild guess, but it may be emulsion damage incurred during confectioning / spooling the film into the cassettes. Since it's significantly beyond the part of the film that's typically used, Kodak may simply not care.