Nitrate film caused many projection booth fires, and was extremely unstable. The Italian film "Cinema Paradiso" incorporates that into the storyline. The projectors required fire traps to help prevent a film gate fire from reaching the full reels. What little nitrate film is still out there is basically not usable as it gets very brittle (and there is the fire danger).
Acetate stock had a problem with a chemical breakdown which would lead to "vinegar syndrome" (the film smells very strongly like vinegar). Also, Eastman stocks would fade, leaving only red. This is often visible on prints from before the mid '80s. After that, LPP (low fade) stock was widely used.
Now, with the advent of digital media, things are more clear cut. All you have to watch out for is hard drive crashes that take out your irreplaceable video completely in an instant
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Well ..... on reading the above, particularly the part about the nitrate film being brittle didn't seem compatable with my old film that I thought for sure was the nitrate type. My film is still nice and flexible. I pull them out every once in a while and play them. Besides the home movies, I have commercial movies like Will Rogers movie, a Charlie Chaplin movie, the corination of Queen Elizibeth, so me old sports newsreels showing old 1930s football games, and some cartoons, and also have a reel with footage taken from a B-17 in WWII. All this OLD stuff is still in good condition, so I did some checking. And as usual, I have to eat my words.
I first did some checking in Wikipedia, and while it agreed with the time frame I was remembering about when the switch from nitrate to acetate took place, it said that this only applied to the commercial movies in big 35mm format, and that the smaller movies in 16mm (which is what I have) were always done on the acetate film. Since some of my film collection is home movies, and some is commercially produced movies, and others are military film, I thought for sure that some of it would have been cellulose nitrate, but I wasn't sure how to check. I was thinking about clipping off a couple frames and seeing if it burned, but Wikipedia also said that you could check by looking along the edge of the film, where it would say either "nitrate" or "safety". So I went downstairs, and checked, and sure enough, ALL of them were "SAFETY". I've been nervous about those movies catching fire for years, mainly because I have a LOT of them, but I guess that I needn't have worried.
HOWEVER, I am still convinced that there was some major change in the film technology in the 1950 time frame, because all of the movies I have that are from the 30s 40s, and early 50s are still good, but the film taken in mid to late 50s and 60s have all deteriorated. So there must have been some other change in the process, perhaps the emulsion or the colored dyes, or maybe chemicals used in the processing. An example of how the old film is still pretty good is
http://www.eskerridge.com/bj/steelers/pass1.jpg , which is from film my father took at a 1940 Steeler/Redskin game. It's a bit scratched up due to a lot of rough use, but the colors and images are still good. Movies taken in the late 50s, are hardly viewable, all bleached out.
Anyway, I was wrong about the acetate base being responsible for the deterioration of 50s-60s era film. It must have been caused by something else.
