Lighten up: design principles for inconspicuous lighting of public art.

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.

Following our in-house mockup, the lighting manufacturer provided a working sample that was used in a second mockup at the site. This mockup proved successful both with sculpture intensity and color rendering. Aiming angles dictated the use of 25-foot-high poles situated among trees wherever possible. Although the fixtures are long, they are small in diameter, and to further reduce their profile, cylindrical ballasts were used and placed in the pole shaft. Where it was evident that overhead lighting would recreate unnatural shadowing, in-ground lighting fixtures were recessed in front of the art to counteract this effect. The result is an idyllic setting that will impart a sense of serenity to visitors.

Unlike the Kelly Drive and International Sculpture Garden outdoor museum, which are Philadelphia-centric exhibits subject to interpretation by those who visit, the Iwo Jima Marine Monument in Arlington, Va., represented a different kind of challenge simply because it is a representation of a real event that occurred at a specific time in our history. The Marine Monument is a memorial tribute for all marines, but especially for the 6,821 servicemen who gave their lives during a 34-day assault on Mount Surabachi in Iwo lima from February to March 1945.

For those unfamiliar with the monument, there are six cast bronze figures, each at a height of 32 feet. The flagpole measures 40 feet from the top to its base. The plinth oil which the servicemen and flag are situated is 10 feet high. The total height of the monument is 78 feet, and is considered to be the world's tallest bronze sculpture.

The original lighting installation consisted of recessing in-ground fixtures cast between the simulated rocks on top of which servicemen stand, placing the American flag in between them. The intent of the artist was to have the sculptured figures floating in the night above ground, creating an eternal moment in time, carved in the heavens.

Through time, this effect was eroded because of water seepage into the light fixtures. In its place, the National Park Service (NPS) maintenance staff located floodlights at ground level situated among the monument's circulation paths, illuminating the entire monument, including the base, which changed the effect from a moment suspended in time to an earth-bound monolith.

It quickly became apparent that the design needed to recreate the inspiration of the original design, yet improve upon its unfortunate creation of uncharacteristic facial shadows. In discussing various lighting considerations with National Park Representative Ranger Andy Wenchel and local architects John Mott and Ellen Jenkins, it became clear that adapting new recessed in-ground fixtures as replacements would not be acceptable because they did not want a reoccurrence of previous water seepage problems. There was a prerequisite from the NPS not to replace the in-ground fixtures located within the plinth.

A full-scale mockup was undertaken with the Fine Arts Commission, NPS, architects and visitors. At that time, we were required to demonstrate a variety of lighting options. Other alternatives were sought that would give the same illusion as originally conceived, and eventually, the theatrical footlight concept as a design alternative and was accepted.

Not to be deterred, we suggested a surface-applied raceway system on top of and along the circumference of the plinth that would contain directional 39-watt metal halide PAR lamps. The raceway, reminiscent of a continuous theatrical footlight, had its vertical surface faced with black granite to simulate the plinth material. The raceway height is six inches and sits back from the lace of the plinth by eight inches. Because of the 10-foot-high plinth, those walking along the monument's paths have no view of the vertically applied granite stone that conceals the raceway.

The lighting system and granite face piece are secured together, like spokes of an umbrella, all going back to a metal band that is mounted to the vertical face of the simulated Iwo Jima rubble and stone. In addition to the footlights, two forward poles were located within trees at diagonal corners to the monument. On these poles, small metal halide PAR lamps illuminate the upper one-third of the monument to flatter any facial shadowing created by the footlights. The installation is now underway, and completion is scheduled for April 2006.

The lighting industry continues to evolve and adapt to changing technologies. New lamp sources in smaller packages with different beam patterns are being developed annually. Unless you are involved in lighting design only, it is difficult to concentrate on these new developments and how to creatively employ their use. It is for this reason that artists and architects should consider consulting with individuals whose profession is to deal in the everyday design with light.

Lighting Design Dos and Don'ts

Dos                                Don'ts

Do retain a professional whose     Don't select lighting hardware
livelihood is lighting design,     for its physical appearance
not the sale of lighting           unless you've seen it in
equipment and light bulbs.         operation and that it performs
                                   to your expectations.
Do retain the professional
lighting consultant in the         Don't downplay the importance
early phases of the project.       of the art illumination by
                                   selecting a competing decorative
Do make sure that the              fixture.
professional understands the
landscape and its environment      Don't look for the easy way out
in which the sculpture is to       as inconspicuous lighting is
be located.                        better and more effective than
                                   the obvious.
Do take into consideration
surrounding buildings, nature      Don't consider any assistance
walks and drives as they all       if the individual assisting is
have sight lines to the piece      to gain by making a sale.
of sculpture to be illuminated.

Do believe that lighting can
make a difference.