Thought I'd update this thread with some findings from my first bulk load of the unlabeled can. Turned out it was Kodak TMax 400 Professional (TMY 5053). Can't tell how old it was... but if my Wiki-fu is strong, looks like the TMY was replaced by TMY-2 in 2007 - so at least 19 years old. Lots of the film was fogged, so someone probably opened the can to take a peek. Still some redeeming shots...
Shooting this film, I obviously had no idea what this was. I metered for ISO 100 hoping for the best. At development, I looked up the possible development times on the Kodak Reference Data Guide I also picked up from the estate sale.
I used D-76 1:1 @ 75°F, while the guide provided guidance at 20°C (68°F):
- TMax 100: 12:00
- TMax 400: 12:30
- Plus-X: 7:00
- Tri-X: 10
Using the longest time of 12:30, the reduction in time between 68°F and 75°F was ~69% based on other films that provide multiple temperature ranges. That put dev on this film around 8:30, which would be exact for TMax, pushing for Plus-X, just a little over for Tri-X, and whatever else the heck it might be would hopefully be okay.
I shot for dev time of 8:00. Fixing time based on leader strip was around 4:30 so double that would put me at 9:00 - I fudged this to 12:00 because I thought it was clearing a lot slower than I expected.
Surprisingly, an ISO 400 film exposed correctly at ISO 100 due to age? Can't really explain it...
- didn't know the film; shot at ISO 100; guessed correctly on dev time 8:00; fixed for 12:00 to be sure; exposed just fine