Identifying Mystery "High-Contrast" Film

I bought two 100-foot bulk rolls of expired film from eBay. One is Plus-X, expired in 1998. The other is in an aluminum canister, with a handwritten "High Contrast" label taped over the original, which was Plus-X. There was also a bulk loader with what turned out to be the last remnants of another Plus-X roll. My theory is that the original owner loaded a pre-1998 Plus-X roll into the bulk loader and then reused the empty canister for whatever the "High Contrast" film was, if it didn't come in a canister itself.

The High-Contrast film is in an unmarked black plastic bag inside the aluminum canister. It is wound onto what feels like a metal spool, not just onto a core as I'm accustomed with bulk film. I loaded a short length of it onto a developing reel in my changing bag and developed it in 510-Pyro for 10 minutes, along with a similar snippet of the film that was in the bulk loader (which I now know to be Plus-X).

The film developed clear with a brownish tint. It has no pre-flashed lettering along the edges. It is drying pretty straight and flat, even when placed on its edge. Any thoughts on what this might be likely to be? See attached image of the mystery High-Contrast film along with the darker grayish Plus-X.

It could very well be this film:


https://blog.jimgrey.net/2025/07/21/film-info-sheet-kodak-high-contrast-copy-film-5069/

Thanks for that link! That seems promising. The info sheet is just what I needed, because it specifies that there are no frame numbers on the 35mm perforated bulk roll version of the film. Do you think that would also mean it has no other lettering along the edges? It's not specified explicitly, but if they didn't frame-number it, perhaps they skipped any edge markings entirely? Quoting: "Forms Available: KoDAK High Contrast Copy Film 135 in 36-exposure magazines (HC135-36); and 35mm, perforated, not frame-numbered, 50 feet on No. 162 spools (HC710)."

Now a follow-up question presents itself... if this is the film, what IE, developer, and developing time I should use to get usable negatives for general-purpose photography. But that is off topic for this thread.

Maybe I'll just try loading a roll, shoot at EI 64 since the data sheet specifies that for tungsten light and I'm accustomed to B&W films having a higher daylight speed than tungsten speed, and see what happens in my favorite developer!

arn_becker said:

Do you think that would also mean it has no other lettering along the edges?

Click to expand...

Probably.
That would have mostly been used in machines designed for record retention of paper documents.

Over the years Kodak produced a number of high contrast copiy films. Photoweare (UJltafinehoue) has sold several including Kodak So 331. I don't know the difference between the version, I did shoot of 331, rated at 25 and developed in a divided developer it was interesting if you experimental. PW gives this link for a user group.

In the late '70s I worked as a technician in a custom lab. We used HCC to make title slides from line artwork. That film was replaced by Technical Pan by the mid-1980s.
Any exposure/ processing instructions you find for HCC will be to make high-contrast results (duh). If you want to use it for normal in-camera photography, you'll have to test. And test again.
Use a low-contrast, dilute developer, Formulary TD-3 might work. Expose generously, with lots of bracketing. You may get something usable.