Lately I have been experimenting with expired film. I have a variety of expired film stocks, but I started with a couple rolls of expired Tri-x since black and white film usually has more latitude than color film. Having gotten a feel for how expired black and white film responds, I was ready to try color. I have about a dozen rolls of both Vericolor III (VPS) and Vericolor 400 (VPH), so those are the two color films I choose to started with.
My experiments with high-speed black and white film seemed to validate the rule of thumb that calls for overexposing film one stop for each decade it has been expired. Kodak Vericolor 400 is a high speed color film, so it would need at least the same amount of compensation. The roll expired in March of 1990, so as a baseline I treated it as an ISO 50 film. The box speed for Vericolor III is 160. Since the emulsion is less sensitive it should degrade somewhat slower than the more sensitive emulsions. I used ISO 40 as a baseline for it, it also expired in March of 1990.
The overexposure that I used for each of the films seemed to produce acceptable results from an exposure perspective. Neither of the films reproduced color correctly, but I don’t think that is a result of exposure. I think that the dyes used in the films degrade at different rates. Both of the rolls were dense, but the negatives from the Vericolor 400 had much more of an orange tint than the negatives from the Vericolor III. That is probably why the Vericolor 400 was less able to reproduce reds in the final images. The Vericolor 400 images above should have had dark pink skies near the horizon, and almost no red can be seen. The Vericolor III did better, but the amazing deep purple’s should have actually been more red to pink. I’m not complaining, I like the result, it’s just not actually how the sky looked that night. Even though the rolls came from the same lot, it is still possible that the rolls experienced different storage conditions. I will compare these rolls to future rolls that I shoot in the lot to look for inconsistencies.
So, I have a couple of takeaways from this batch of experiments. First, it seems that all ISO 400 film, not just black and white, should be overexposed one stop for every ten years it is expired. Lower ISO film doesn’t seem to need as much overexposure. For ISO 160 film it may be appropriate to overexpose one stop for every 15 years it is expired. I’m going to stop attempting to formularize overexposure for now and just work on expanding the rules of thumb. The second takeaway is that individual colors, especially red, in different color film stock can degrade at different rates. More experimentation will be needed to see if there is consistency in how colors degrade for any given film stock.
|Film Type||Rule of Thumb|
|ISO 400 b&w film||overexpose 1 stop for every 10 years expired|
|ISO 400 color film||overexpose 1 stop for every 10 years expired|
|ISO 160 color film||overexpose 1 stop for every 15 years expired|