My father's Kodachrome slides from the 1950s, 1960s, 1970s and early 1980s look as though they were shot and processed last week; the colors are as rich and vibrant as - I would guess - they day they were shot. His Ektachromes from the 1950s and early 1960s (when he apparently gave up on the film) are of uneven condition: some look almost as good as the Kodachromes; others have a blue cast. Perhaps the determining factor is the quality of processing? His small collection of Fujichrome slides - all shot between 1974 and 1976 - look like s#*t: all have faded to magenta (all are in Fujichrome cardboard mounts). Dad's collection was stored for its entire life in his "man cave" (i.e. his basement den, with a humidity of around 45-50 per cent (humidifier) and a year round temperature of 18-20C (68-70F range, more or less).