3.6 Light, ultraviolet (uv) radiation, x-rays

3.6.1 Light and ultraviolet radiation have several deteriorating effects on audiovisual carriers. Many polymers, e.g. PVC, deteriorate under prolonged or permanent exposure to light. Extremely dangerous is the influence of light to the life of recordable optical discs (“dye discs”). Tests have shown that permanent exposure of such discs to daylight—and specifically direct sunlight—can render them unreadable within weeks.18 To what extent small doses of light over a period of years would influence such discs stored in their containers, but not in dark archival rooms, has not been explored. It is, therefore, wise to avoid any unnecessary exposure of all audio and video carriers to light, and to pay particular attention to ensure that any direct sunlight, which may also cause temperatures above safe limits, is inhibited.

Several audiovisual archives have installed low uv light systems in their storage rooms. This is a wise precaution particularly in busy archives where lights are kept switched on for long periods or permanently.

3.6.2 X-rays, as emitted from airport equipment, has, as opposed to undeveloped films, no influence on audio and video carriers. Tests have shown that extremely high, lethal doses used to decontaminate objects from germs such as anthrax spores, do not harm the recorded signals. It is not known, however, whether and to what extent such treatment may influence the further life expectancy of treated materials.

18. Kunej 2001.