so i had an experience with expired (in 1991) fujichrome 50, and all the shots look overexposed by one-twe stops. after some research i found out that:
Negative films fog darker with age (or temperature), as grains get thermally, chemically, or cosmic ray exposed. Negative films have a large exposure latitude, so you can increase exposure to get above the fog.
Reversal films fog lighter with age. That is why photos may look overexposed. But they don’t have the large exposure latitude, so you can’t increase exposure to get above the fog. You are squeezed between fog and the top of the curve.
#photography #slide #reversal #negative #positive #fujichrome #film #filmphotography #expired