The Star-Spangled Banner, a national treasure and the central artifact of the Smithsonian's National Museum of American History, is displayed on a table with a slight incline for easy viewing in a carefully fabricated two-story high climate controlled case. Given the preservation requirements of minimized exposure to light, the lighting solution was to provide a uniformly illuminated level of one footcandle across the entire artifact. This is achieved with a single source of light that is carefully calibrated to maintain uniform light levels.
The viewing platform is by design the least illuminated zone in the exhibit dedicated to the Star-Spangled Banner. Finishes were strategically chosen by the design team to ensure that the Star-Spangled Banner could be viewed in a comfortable manner without distractions in the glass surface. The areas leading to and from the viewing area were carefully designed to foster smooth transitions for eye adaptation given the change in light levels.
The interior finishes and surface treatments at the viewing platform were selected to absorb as much light as possible to provide appropriate levels of contrast and optimal viewing conditions of the artifact, which is illuminated according to conservation guidelines.
Given the historical significance of this object, all equipment and devices are external to the display environment. A light attic separated from the display case allows for illumination with good color rendering. The Star-Spangled Banner is lit using a single projector that carefully displays a calibrated image that function as a light reduction screen on the display table. This method of visible light control is capable of maintaining a uniformity of 1 footcandle with /- 0.25 footcandle variation from this lighting baseline.
Lighting section detail at the light attic, showing the projector on a movable steel armature and wall-mounted monitor.
Lighting plan detail at the light attic, showing the projector on a movable steel armature and wall-mounted monitor.