I'm just getting back into film photography and have some film, mainly Jessops, left over from my film days around 20 years ago!
From what I've read, if the film hasn't been kept in a fridge/deep freeze, you should overexpose by 1 stop for every 10 years, ie for 20 year old 200 ISO film shoot it as if it was 50 ISO.
From my limited experience (4 rolls of 20 year old expired film) a roll of Kodak Gold 200 ISO metered at 100 ISO gave good results (colours a bit muted) and the first roll of Jessops SHR 200, also metered at 100 ISO was reasonable too bit not as good as the Kodak. Using the above rule they both should have been shot at 50 ISO but dull wintery days in Scotland don't give much light, hence my decision to modify the rule!
The next roll of Jessops 200 I did shoot at 50 ISO but the results were very poor, images weren't sharp and colours were bad - apart from the first 3 shots when I hadn't realised that although the camera (Olympus OM2) was set to auto, the shutter was set to B and therefore remained open as long as I held it down (I thought the shutter sounded odd on the first shot but it took another 2 shots before I realised why!), so they should have been overexposed but they actually looked pretty good. I therefore decided to shoot the next roll of Jessops 200 at 25 ISO when we next got a brightish Saturday or Sunday, which was this morning. I developed it this afternoon and the negatives certainly look better but the acid test will be once the film has dried and I can scan the negatives and see the colours and sharpness.
I've still got more rolls of old film so experiments continue!
