Quote Originally Posted by Steve Smith View Post
I have used some K64 which was twenty five years out of date and always kept at room temperature and all it had was a slightly cooler look than normal so I don't think we need to worry too much about it.

Which brings me to this question:

How does a non-substantive colour reversal film get shifts in colour with age if the colour dyes are not added until processing?

I have ~10-15 rolls of Kodachrome (K-14) dating from ~1982-1998.