p.7 #2How long do you think a latent image lasts on undeveloped film?
I haven't looked through all the posts, but I agree with coralnut. I found some frozen 4x5 Efke film (a Croatian film as I recall) that had been exposed maybe 15 years ago. After some tests with the same film (same box actually, unexposed and frozen), I found that exposed film developed very "thin" negatives. I'm confident in my exposures (from 15 years ago, since I was shooting 4x5 back then). All I could conclude was that the film lost some of its latent image. This was a "silver rich" film made in a "traditional fashion," and I believe that manufacturers like Kodak and Ilford have found a lot of tricks to make their latent images stable, low reciprocity, low retriculation, etc, which has improved the film. They made good film, but it's expensive.
So, how long does the image last depends, I believe, on both the film and the storage conditions.