LIGHT PIPING: A NEW LIGHTING SYSTEM FOR MUSEUM CASES
In November 1988, Field Museum opened its Inside Ancient Egypt exhibit. This exhibit utilizes a new lighting system to illuminate a large case, a reconstructed shrine, and simulated burial niches. This system, referred to at Field Museum as “light piping,” is based on the technology of prismatic film first developed by TIR Systems of Canada and further developed and marketed by 3M Corporation for commercial lighting and sign-age. The potential of the system for museum exhibit lighting was recognized by Paul Martin, then lighting designer at Field Museum, who developed the light piping illuminators described in this paper.
The light piping system is a radical departure from the lighting systems previously used in the museum. In other exhibits, the majority of display cases utilize fluorescent lamps in boxes located on the top of each case. Previous temporary installations have used incandescent lighting. These lighting methods have been of concern to conservators for several reasons. First, the light boxes utilize fluorescent lamps that emit ultraviolet light, which is damaging to many of the objects inside the cases. Ultraviolet-absorbing sleeves have only recently been used to limit ultraviolet emissions. Second, accidents have occurred when light bulbs were replaced; for example, falling bulbs or tools have broken objects inside the cases. In addition, starting with the Inside Ancient Egypt exhibit, the climate inside most of the cases is controlled with humidity modules (Sease 1990, 1991). The environmental control of these cases would be disrupted by servicing light fixtures within them, and thereby subjecting their contents to sudden changes in relative humidity.
As the light boxes are located on top of cases and are vented, heat buildup within the cases is not an issue at Field Museum. It is, however, an important conservation consideration in museums in which exhibit cases have internal light fixtures.
To eliminate the problems of heat buildup inside cases and the disruption of cases when light bulbs or fixtures are changed, the light piping system was chosen as the best means of lighting the somewhat unusual Inside Ancient Egypt cases. Light pipe illuminators provide a flexible, cost-effective means of safely lighting display cases while at the same time providing maximum flexibility and creativity to exhibit designers. The piping system can be used to get light into otherwise inaccessible areas. An added advantage to the piping system is that it does not detract from the ambience of a case re-creating a historical or natural history scene, such as a period room or a diorama. In such situations, modern light fixtures are out of place and distracting. Based on our experience with this exhibit, we feel the light piping system has tremendous potential for use in the exhibition of all kinds of museum collections.