I recently came across a large lot of expired 120 film. The lot included a variety of black and white and color films with a wide range of expiration dates, and the price per roll was a fraction of the cost of new film. I snatched it up. The idea is to perform some informal experiments to see how various films have held up over time, the unknown storage condition notwithstanding, and to test some common axioms used when shooting expired film.
One of the axioms that I want to test, perhaps the only one, is that it is necessary to add one stop for each decade a film has been expired. I have looked for a formula or chart that would help me understand how the base density of film increases over time, but I was unable to find one. Kodak provides some information regarding film degradation in their film storage guidelines, but nothing about the rate of decay due to gamma radiation or negligent storage. So as I use this lot of film I will be looking to corroborate that maxim.
Update: I have started compiling a system of rules of thumbs for shooting expired film.
For the first roll in this series of experiments I went with one of my favorites, Kodak Tri-X. This particular roll expired in September of 1976 and is one of the older rolls, so it should only get better from here. This film was shot at box speed, well 320, which is habitually how I rate Tri-X for some reason. Almost all shots were exposed as metered with a Sekonic L-308. The exceptions are noted in the image captions, but they are probably obvious. And, though it looks like I thoughtlessly used reflective metering, I used incident metering as appropriate for almost all the shots. Oh, I also used a K2 filter (yellow 8), because that’s what Edward Weston would have done.
Having stared at the scans and negatives for I while, I have a few observations. First, it appears that there is merit to overexposing expired film. The only image which looks remotely correct is the one which was overexposed by 2⅓ stops. On the next roll of expired Tri-X I will do proper bracketing, at least after the first 3 frames. That’s because my second observation is that the first few frames, the ones closer to the exterior, seem to be denser. Unfortunately I don’t have a densitometer to verify that.
As you can see, and perhaps as you expected, none of these photos turned out very well at all. But that’s alright, it’s just a good reason to go out and shoot another roll.