Of all the films produced during the silent era (1895–1930), approximately 95 percent have been lost. Of all films produced during the nitrate sound film era (1930–1955), only about 50 percent survive in any form. Even many films from the most recent years of film history have failed to survive, due to color fading, marginal status (industrial films), and archaic formats (for example, Cinerama). Probably as much as 60 percent of all television production has been lost.
Films from the entire nitrate era (1895–1955, silent and sound) have decomposed due to poor storage conditions. In the first stage of decomposition, the film turns sticky, while the image disappears in a gelatinous mass. In the second phase, the film roll solidifies into a hard disk, making the retrieval of any images virtually impossible. Finally, the material turns into a brown powder. Since nitrate film is highly flammable, many films were lost in fires. In fact, it was not uncommon for commercial film companies to burn their vault holdings because they saw old films as merely a liability and an expense once they had made their initial theatrical runs. Not until the advent of television and later consumer video were rereleases of economic interest to the major corporate studios.
Other problems of film stability appeared with time. In the 1970s, it was discovered that newer acetate films decomposed through what was termed the "vinegar syndrome." Rather than turning gooey, the films became brittle and buckled, making them unprojectable. Color film was also subject to decay. While the old Technicolor films have remained relatively stable, color film stocks from the 1950s (Eastmancolor) have been subject to extreme fading, leaving prints and negatives looking pink after only two decades or less. Finally, the advent of television and video brought with it more than three dozen television and video formats that appeared and disappeared over the last forty years, making it necessary to preserve not only the electronic moving images in these formats but also the equipment that played them. For example, many two-inch quad tapes (the first videotape format from the late 1950s) can no longer be accessed because the large and cumbersome machines used to play such tapes no longer exist. Unlike film material, which can be viewed with the naked eye or with standardized projectors, videotapes are encoded and decoded by machines from specific manufacturers and are usually incompatible with machines from another manufacturer.
The whole area of digital information preservation and access, whether on the Internet or on DVDs and other new digital media, compounds issues of format migration and is only now being confronted by moving image and sound archivists. For film and television archivists, these new media present ever greater challenges, given a lack of standardization on the one hand and the ephemeral nature of the media on the other. Formats are appearing and disappearing even more rapidly than was the case with analog video, making preservation a complex issue, indeed. Furthermore, many classic films still held by copyright holders are being digitized and often manipulated in ways not intended by the original producers, making them more commercial but no longer true to their original content and form. For example, recent DVD "restorations" of some classic Technicolor musicals no longer look like the original Technicolor, which is characterized by garish color and a slightly soft focus, because it is now possible to eliminate these "defects" digitally.