The Liberty Bell, America's symbol of freedom, is safely nestled in its new home on Independence Mall in Philadelphia, PA. The Bell is now just steps away from its former home in historic Independence Hall where our nation's founding fathers signed the Declaration of Independence in 1776. Designed by the Philadelphia architectural firm of Bohlin Cywinski Jackson (design principal Bernard Cywinski; design architect Ken Mitchell; Jeffrey Lew project manager), the new red brick Liberty Bell Center has a glass wall that allows the Bell to be bathed in sunlight during the day and seen from the exterior of the pavilion at night. The lighting design involves daylight compensation as well as 360Þ lighting of a dark bronze object.
Lighting for this historic icon and its new home (on the site of George Washington's home during the Continental Congress) was designed by Grenald Waldron Associates, based in Narberth, PA. Ray Grenald served as design principal, with Dan Edenbaum as project designer and project manager (Edenbaum is now president of Drago Illumination in Ardmore, PA). “In looking at the Bell, we asked ourselves what impact we wanted it to have on the public,” says Grenald. “Not only is it the holy grail of liberty, but a symbol that gets more and more symbolic as time goes by. The architects were very conscious of this and decided to really put the focus on the bell.”
A native of the Philadelphia area, Edenbaum remembers visiting the the Liberty Bell as a child. “As a result of having literally grown up with the Bell as a revered icon, I was compelled and eager to be involved with the lighting design for its new home,” he says. “Work on the lighting design began in March of 1999.” The project involved working with the National Park Service (the client), as well as diverse design teams, as the new Liberty Bell Center is part of a three-block historic site. Of concern was not only the design concept, but also the installation and operational costs of a lighting system.
“One of the things that Bernie Cywinski said in a meeting early on in the design process that struck me and gave the design focus was that when you approached the Bell he wanted it to be almost a ‘holy experience.’ He wanted you to feel like you were stepping on ‘sacred or hallowed ground.’ The image of the Bell should be that powerful,” notes Edenbaum. “To help determine the best way to illuminate the Liberty Bell itself, early on through the initial design process, Ray Grenald and I agreed that a mockup on the actual Liberty Bell was going to be necessary to ensure that what we were designing on paper would turn out like we expected it to in real life.”
The designers' concern was based on the dark bronze surface of the Liberty Bell. “We needed to strike the right balance of light qualitatively, quantitatively, and chromatically,” Edenbaum points out. The 30' ceiling height in the Bell chamber meant that incandescent lighting was not practical (too many watts, says Edenbaum). Instead, Philips WhiteSon 50W ceramic high pressure sodium and Par30 70W Philips Master Color ceramic metal halide lamps were used with Nokia track and Indy track heads that tilt and rotate for extra flexibility. The track is placed in a pocket along the ceiling and is meant to disappear as much as possible.
“To help create the dramatic impact, the light beams had to be tight and well controlled, capable of accenting a 3' by 4' object from 30' in the air with as little spill light as possible,” says Edenbaum. Yet the glass curtain wall allows sunlight to stream in, requiring compensation for high levels of daylight on one side to be factored into the lighting design.
“For the mockup, the Park Service was very co-operative and the design team was allowed to bring an assortment of lighting instruments into the Old Pavilion to do some tests after hours one night in October of 1999,” Edenbaum recalls. “Through that mockup we determined that a mixture of ceramic high pressure sodium and ceramic metal halide was going to provide the right mix of color to enrich the dark bronze while also providing the intensity needed to give the Bell highlights and luster.”
Calling upon his dance and theatre lighting background, Edenbaum set out to light the Bell as if lighting a ballerina on stage, using the two distinct colors and intensities of ceramic high pressure sodium and ceramic metal halide to help render, or model the shape of the Bell.
“By alternating the color and intensity of the light around the Bell, it is modeled more three dimensionally than if only a single color or intensity was used,” he notes. As many as six metal halides paired with three sodium lamps might hit the bell in one spot to help with the sculpting, and combat the high sunlight.
The control system, a Leviton 8000 Series, is used with photocells to allow for daylight compensation. “It stood to reason that if there are high enough levels of daylight, we should be able to turn some of the lights ‘off,’ thereby extending the maintenance cycles and lower operating costs,” says Edenbaum.
“Because the Park Service operates their facilities with rotating staffs we knew we had to design a system that is extremely simple to operate, yet flexible enough to be able to adapt to different or future programming needs. The control system was designed so that when the facility opens in the morning the Park Ranger has to touch one button which puts all of the sub-systems into a pre-determined scene, and then activates daylight harvesting via the photocells. At night when the facility closes again, the push of one button puts the Bell Chamber and Exhibit Hall into nighttime viewing scenes, and ensures that all others subsystems are turned ‘off.’ A time clock controls activation of the exterior areas. In this manner the building really almost takes care of itself.”
By fall 2003, the Bell was set to be moved into its new home. The schedule leading up to the opening ceremony meant that Edenbaum had to aim the lights for the Bell before it was actually in place. “To facilitate this, the architect provided a to-scale foam core cut-out of the Bell,” he notes. “Keeping in mind that we were evaluating lighting on a white foam core cut-out, everything looked good.” But there was no way evaluate or make adjustments to the lighting, or controls, until the Bell was in place and the audience was there for the grand unveiling event.
“The mockup early in the design process was absolutely invaluable,” Edenbaum adds. “For the first few weeks after the opening several of the design team members would occasionally visit the Bell at its new home. The nature of the daylight in the building changes a lot during the course of the day, and it will continually change during the course of the year as the angle of the sun changes.”
To add to the dramatic impact of the Bell, the design of the pavilion brings visitors through an exhibit area that houses historic documents and information. “People see ‘relatively,’ compared to what they see before,” says Grenald. With this in mind, and to ennoble the Bell, the rest of the building was designed to be subordinate.
As a result the exhibit area has a low ceiling with gray acoustic tile and a granite wall. It is also a noisy space with an intentionally confined feeling to increase the contrast with the volume of the Bell chamber. Lighting in the exhibit area is a low voltage cable system by Bruck Lighting with 50W MR16 lamps. The cables are stretched between supports cantilevered from the walls, and integrated seamlessly into the architecture.
“In its old home the Bell looked black, not bronze,” says Grenald. “Now when you walk from the exhibit area, a dark closet so to speak, into the bright Bell chamber, it is sitting there like a little jewel. The room is very quiet and the light is very strongly focused on the Bell. It is a very moving experience. Something that has touched your soul.”