I have a bag of film that I’ve been toting around with me for the past 15-20 or so years. From the boxes, the film “expired” around 2002 or thereabouts.
I shot a couple of rolls of it and things looked OK. I was looking at the density of the resultant negatives, and I was a tad disappointed. I developed a new roll of Ilford Delta 400 today, and it looked quite a bit different from the old Kodak T-MAX 400 TMY that I shot. I’m not talking about minute details about how it renders the picture; I’m talking about the gross level of density on the roll.
So I decided to look a bit deeper into the topic. I found an article from Popular Photography about exactly this.
This article confirmed my suspicions. It seems that film starts to lose speed over time. Since I’m working with two-decade-old film, I’ll have to downrate the speed by about a full stop. That makes sense given my results. So the 400-speed film is now a 200, and the 100 is now 50. Of course, I can develop it longer, but that brings up other potential issues like fogging.
I have enough of the film around to conduct some real experiments to see how to use it in the present. That said, I think I can safely say that I shouldn’t use it for things that I really want to preserve. But, I think I’ll first just try to develop a bit longer and see what the results hold.