Here's a short brief of how I expose all of my expired film, and the exposure times and ISO I used. This tipster also tells about how different expiration dates influence the speed of the film.
Photographers around the world have always been using expired film to get saturated pictures and other effects according to the expiration date of the film. What we can consider as expired film are those that are a couple of years older than its expiry date.
A film that has a couple of months passed its expiry date, will not provide different results than an non-expired film.
Usually, I overexpose by one stop and edit in Photoshop or select some options of color correction before scanning, in order to get results similar as a cross-processed film. Here are some results applying this method.
There’s a rule that states that a film loses one stop of its speed after a decade of expiry. So, if you’re lucky to own a film with 10-20 years of expiry, apply this rule. At each 10 years underexpose by one stop. If it’s ISO 400, after 10 years will be ISO 200.