Audiovisual documents

Since the invention of the cinema in 1895, several means have successively enabled the broadcasting of moving images.

The first, silver film, evolved in 1900 with the first sound film. In 1935, colour film made its appearance. Silver film reels are mainly available in 8mm, 16mm and 35mm formats. Several components were used over the years: cellulose nitrate, which was banned from the 1950s because it was highly flammable, cellulose acetate, which triggered vinegar syndrome if the document was poorly preserved, and, finally, from 1990, polyester, which is chemically stable.

However, it was with the magnetic tape that video was democratised. After the first video with an analogue signal (Quadruplex 2″) in 1956 and the first U-Matic cassette marketed in 1971, the invention of the VHS in 1975 enabled it to be distributed to a wide audience. In 1986, the image and sound quality were improved with the appearance of Betacam. Other formats less known to the general public, such as Betacam SP or S-VHS, were used by professionals.

From the mid-1990s onwards, the emergence of digital technology, first stored on magnetic tapes (digital Betacam, then DVCAM and Mini DV), then on optical discs (CD, then DVD), accentuated the process of dematerialisation of video, until the dematerialisation that we know today.

While film-based media can be preserved well, provided they are stored in a warehouse with low temperature and relative humidity, the life of magnetic tapes and optical discs is much more limited, as the materials used for their production are much less chemically stable.