Keepers of the Frame (1999)

An exploration of film preservation and restoration in the United States. We learn about nitrate film, which turns gummy before either disintegrating or burning, and which can cause nearby films to also go bad. We see "safety" film, which can also deteriorate with "vinegar syndrome." We see some of the places where films, once thought to have no lasting value, were discarded and rediscovered decades later. Soundtracks are often on film and are prone to the same problems, or for the earliest sound films, are on separate discs that often get separated from the film. Colors can fade, sometimes to the extent that the image is gone. The impressive Cinerama format has been abandoned except for some dedicated enthusiasts. Also worth preserving, but presenting their own problems, are avant-garde/experimental films and home movies.