What is this film a friend found?

[MCB18]

friend I know just found a giant roll of 5” film in an aerial magazine, and they have no clue what it is. It’s on a 0.21mm (8.2 thou) base, and doesn’t react to anything they have put it in. Dev, fix, C-41, household bleach… no legible markings on the spool or magazine. I am extremely curious about what this is.
A

(And yes, obviously the part they unrolled is ruined, but that still doesn’t explain it not clearing in Fix…)

 

[loccdor]

Could it be a non-photosensitive leader?

 

[MCB18]

Could it be a non-photosensitive leader?

That’s the first thing I suggested, he said he spooled out quite a bit and it was all the same stuff

 

[Don_ih]

I have a roll of aerial Super XX (super old, obviously) that specifies it has 15 feet of leader and trailer. But that is also just more film (which is great - 30 feet more film than you'd expect - which would be great, but it's 70 years old....).

 

[MCB18]

I have a roll of aerial Super XX (super old, obviously) that specifies it has 15 feet of leader and trailer. But that is also just more film (which is great - 30 feet more film than you'd expect - which would be great, but it's 70 years old....).

I have seen old cans of aerial film that specifically say “opaque leader/trailer“ on them. So I do know that it is a thing, but the dude said he wound off around 30 feet of this stuff whatever it is, and it just keeps going. I don’t know if it’s some really weird thermal developed film or something weird like that, but whatever it is, it’s not normal. Like this stuff is almost 50% thicker than sheet film!

 

[mshchem]

I have seen old cans of aerial film that specifically say “opaque leader/trailer“ on them. So I do know that it is a thing, but the dude said he wound off around 30 feet of this stuff whatever it is, and it just keeps going. I don’t know if it’s some really weird thermal developed film or something weird like that, but whatever it is, it’s not normal. Like this stuff is almost 50% thicker than sheet film!

Dip it into real freaking hot water, if it has a gelatin emulsion it should come off. Otherwise I suspect it is a leader or some other non-photographic plastic film. Could just be dyed base.

 

[MCB18]

Boiling water did nothing, so best guess is that it’s probably some kind of leader tape meant to thread equipment with.