Since it is not possible to keep collections completely in the dark at all times, staff must compromise to provide the minimum amount of light necessary for the tasks being performed, such as exhibition, research, or searching the stacks. Lighting during research and storage will be considered here; see Session 5: Collections Care for more information on exhibition.
Controlling UV light depends on eliminating or filtering sources of light with a high UV component (e.g., natural daylight, and fluorescent, tungsten-halogen, and metal halide bulbs). UV filtering film can be applied to windows. Blinds, shades, or heavy curtains will control UV light (as well as visible light and infrared light). In areas lighted by fluorescent bulbs, low-UV fluorescent bulbs or UV-filtering sleeves must be used. If filtering sleeves are used, they must be transferred to the new bulb when the bulbs are changed.
Natural light should be blocked completely from storage areas. Lights should be turned off when storage areas are not in use, and light levels should be kept as low as possible. Rearrange shelving and collections so that light does not fall directly on collections. Boxing or placing materials in folders and drawers will also protect them. Any reduction of light reduces long-term damage. Each institution should develop guidelines and implement them to control light where collections are used or stored.
See a Light Control Checklist (PDF, 232k).