Shot some really expired C41 film, got to the lab, they recommended a one stop push processing due to the age of the roll. Got the result back, absolutely stunning colours and sharpness, no grains to speak of. Still got 9 more rolls to go. But the push processing makes it a bit more expensive than I feel I can afford. So can I shoot this ASA 100 speed film at 50 instead and process as usual? Or is there any other differences I should think about? The film in question was a 120 roll film of fuji susperia expired in '96.