Storage and Care of Architectural Records

Damage from light is cumulative and nonreversible. The energy in visible and non-visible light is sufficient to drive degradation reactions such as fading of media, or darkening and embrittlement of wood-based papers. Materials should be protected from overexposure due to direct sunlight and from constant interior lighting. If materials are stored in a lit office, viewing room or stack environment, exposure may be controlled by boxing, sleeving or covering materials when not in use. Windows can be covered with blinds or curtains, or window panes with ultra-violet (UV) filtering film (also useful for covering glass-fronted bookcase doors) or double UV filter glazing. Fluorescent lights, which emit higher amounts of UV but less heat than incandescent bulbs, may be shielded with special UV filtering sleeves for the bulbs or with diffusers on the fixtures. Filters and diffusion reduce the amount of UV light, but do not eliminate damage completely. Meters can also be used for testing the efficacy of UV filters over time. Motion-sensing lights or timers can help to reduce light exposure in lesser-used spaces, as well as reduce energy costs. Light levels in exhibition, reading or storage spaces can be monitored with a light meter capable of taking UV and visible light readings. Some types of colored images (blueprints and sepias, drawings made with watercolor, pastel, marker or colored pencil) are extremely susceptible to fading and should be viewed in controlled conditions. In a reading room environment, these materials should be covered with a larger piece of clean acid-free paper whenever they are not in current use.