New developments in museum lighting design

Photos © Nic Lehoux

by Scott Newman, FAIA
Museums employ two key strategies for lighting works of art: daylighting and artificial or electric lighting. (The author would like to thank Thomas Holzmann and Gregory Weithman, AIA, for their contributions to this article.) For the Whitney Museum of American Art in New York City, architects Cooper Robertson and Renzo Piano Building Workshop collaborated extensively with Arup consulting engineers, as well as museum curators and conservators, to design suitable solutions for both imperatives.

Historical gallery design minimized daylight, maximized wall surface, and consequently turned museums and visitor experience inward. When architects did introduce daylight into galleries, it arrived heavily filtered through skylights or clerestories with laylights. Tall volumes of space above the laylights and below the exterior skylight functioned as daylight mixing chambers, employing several layers of filtration and diffusion before light reached the galleries below within an acceptable foot-candle range relative to the type of media on display. This system ensured daylight would not damage sensitive works of art, but also meant gallery visitors rarely had views to the exterior.

The new Whitney Museum of American Art represents a significant change in attitude toward daylight in galleries. The museum design provides a seamless indoor/outdoor experience on each gallery floor with a variety of opportunities to experience the city beyond.

Daylighting reduces the need for artificial illumination, allows works to be shown in the full light spectrum in which they were conceived, and accentuates the three-dimensional quality of sculpture. Technology and careful analysis of programmatic constraints enable this approach while still preserving safe light and environmental levels for the art.

Glazing, motorized roller shades, and flexibility
At the Whitney Museum, the use of glazing on all building façades—not solely those facing north—demonstrates the design possibilities enabled by technical invention. To incorporate this level of glazing, the design team employed insulated glass units (IGUs) with warm-colored edge spacers, as well as clear, low-iron glass with neutral coatings and minimal reflectivity and distortion. A polyvinyl butyral (PVB) and ultraviolet (UV) interlayer is sandwiched between the glass sheets, filtering more than 99 percent of harmful UV radiation. These measures alone are enough to protect the artwork from damage (except in direct sun) and increase the building’s energy efficiency.

Interior roller shades throughout the museum allow for further modulation of daylight during bright times of the day. The Whitney’s design team worked closely with the shade manufacturer to develop the appropriate technical approach to the light control systems. Shades are typically deployed from the ceiling, covering the windows as well as the doors, while interior and roof-mounted sensors track the daylight as it moves around the building. The shades are most often used in bright sunlight; on cloudy days or during the evening, they may be programmed to retract to allow maximum daylight.

For comprehensive control of light transmission, and to provide full sun exclusion from the windows, a 101-mm (4-in.) wide, graduated ceramic frit precludes light from entering the galleries via the 25-mm (1-in.) gap between the shades and the mullions.

Vertical façades within the museum’s galleries are provided with two layers of motorized shades:

  • one for solar/glare control, which cuts down the intensity of light entering the windows; and
  • another for diffusion/light control, which disperses the light that does manage to filter in.
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