n. (also UV filter)a material that absorbs ultraviolet radiationLeisinger 1963, 77Ultraviolet filters, temperature and humidity controls, filtered air-conditioning systems, electronic alarms, and good exhibit equipment have made the permanent or semipermanent exhibit a possibility.Crews 1989, 122FOUR TYPES OF ULTRAVIOLET FILTERS were evaluated for their effectiveness in reducing fading of wool dyed with selected natural dyes and one synthetic dye. . . . The control specimens colored yellow with the weld dye retained more of their yellow color because of the yellowing of the wool substrate whereas the weld-dyed specimens exposed to light behind UV filter underwent no yellowing, only fading caused by the visible radiation. Ritzenthaler 2010, 137Ultraviolet filters, which contain UV absorbers, are available in many forms, including rigid acrylic sheets, flexible film or foil (either polyester or acetate), or as a coating or varnish. Plain window glass will filter UV radiation below 325 nanometers but transmits UV radiation between 325 and 400 nanometers (it is possible, however, to have glass sandwiches custom-made with a UV filtering film interlayer). To be effective, a UV filter must be well fitted to ensure that all light passes through the filter rather than leaking out at its edges.
Filters are used between light sources and archival resouces to reduce degradation from ultraviolet radiation (also known as ultraviolet light). Common forms of ultraviolet filters include film placed on windows or plastic shields placed around fluorescent bulbs.