Lighten up: design principles for inconspicuous lighting of public art

Parks & Recreation, Oct, 2005 by John Sarkioglu

It is generally understood that public art is a free-standing and three-dimensional form, often site-specific and varying in size. Public art, in part, conveys our history. The resulting imagery, be it life-like or contemporary in appearance, is the product of the artist's integrity, creativity and skill. Public art may be found in every urban, suburban and rural community, be it on the sidewalk or on grass within a park. Although materials and methods of construction vary, from painted surfaces to cast metals, most often the art objects are dark and fade away in the evening under the fall of darkness.

Lighting public art is an art form in itself. Each sculpture or exhibit requires customized lighting design that is dependent on the natural environment and the landscape, and requires different design creativity for each project.

When the Fairmount Park Art Association, under the direction of Director Penny Balkin Bach and Assistant Director Laura Griffith, undertook a program to illuminate two of its public art projects, it wanted to call attention to the richness of their public art, which had gone unnoticed because of its surrounding darkness. Philadelphia is known to have more public art than most cities in the U.S.

To highlight this art legacy, local monies became available and programs were established to promote their day-time and evening visibility. Our lighting design firm was commissioned to focus on two areas: Kelly Drive and the International Sculpture Garden.

Kelly Drive is a meandering drive through the Philadelphia Fairmount Park system that parallels the Schuylkill River with sculpture located on both sides of the roadway. University boathouses that house scull shells for racing dot a major portion of the area between the river and the roadway. A bike path and sidewalk parallel the road.

As one might imagine, vehicles, joggers, scull racing, baby strollers, cyclists and in-line skaters create a unique energy in and around the 40 pieces of public art that adorn each side of the roadway. Unlike a museum setting where one's sight line to a flat object of art is some what fixed, outdoor art has a varying sight line from varying elevations looking from different speeds.

Mother nature has a flattering way of lighting outdoor art. Not only does the art become illuminated from the sun directly, sometimes modeling the art--where one side is brighter than the other by using thousands of foot candles of light striking the surface--redirects the rays of light upward in a flattering way onto the sculpture. These redirected rays of light are forgiving as they reduce shadows created by the intense overhead sunlight.

Our role as lighting designers is to attempt to recreate this natural lighting affect with artificial light. In order to accomplish this for Fairmount Park's sculptures, the design firm undertook full-scale mockups for six of the 13 sculptures to review sight lines and lighting intensities.

Because some of the sculpture pieces were required to be seen from across the roadway, lighting hardware was mounted to city poles and aimed at directions that would have the back of the fixture facing traffic leaving the city. We used relatively small lighting fixtures that were about 6 inches in diameter by 9 inches long with louver guards and metal halide lamps.

Ballasts were removed and relocated to the opposite side of the pole to further reduce the fixture profile. Because the optics are within the family of parabolic aluminized reflector (PAR) lamps used, it enabled the design team to use one fixture type.

To replicate the sun's natural indirect effect, bunkers were built into the ground in front of the object. When city poles were not available, we incorporated new 5-inch diameter poles at 45-degree angles in front of the sculpture to house the hardware necessary to create illumination from above. In these instances, the same lighting fixtures were used; however, the ballasts were cylindrical and situated with the pole shaft, again to reduce the profile of the visible lighting fixture. All lighting materials were painted to blend with the natural environment.

Unlike the Kelly Drive commission, the International Sculpture Garden at the foot of Penn's Landing is like a museum without cover. Although the International Sculpture Garden existed, the new scope of work required a change of grade and elevation, necessitating the removal, relocation and expansion of the area to support additional three-dimensional sculpture work. Full-scale mockups were undertaken to renew aiming angles and intensity of light on sculpture and walking pathways.

We initially began our first mockup using a 39-watt metal halide PAR lamp. Although at this point in time it is the smallest lamp available, it was determined to be brighter than necessary. The design consideration was to render this outdoor museum as if it were in a living room: soft and flattering. To achieve this reduced diffused effect, we met with the lighting fixture manufacturer in our in-house mockup facility, who agreed to further elongate its standard 3-inch diameter by 6-inch-long fixture. As an extension to this standard fixture, we added a 1.5-inch diameter by 12-inch-long snoot that reduces the diameter of the lamp imagery and intensity on the objects. With a 1.5-inch fixture diameter, visible light leaving the fixture became almost non-existent.