The Utah State Capitol was designed by Utah architect Richard K.A. Kletting in 1912 and completed in 1916.
The building’s exterior nighttime lighting composition sought to reproduce the architect’s original design concept, while adopting current lighting and lighting control technologies. The 300-foot dome is gently, yet precisely illuminated from rooftop corners with tightly controlled 400W metal halide floodlights. Uplighting of the dome’s interior is accomplished with 70W ceramic discharge metal halide lamps and in turn provides a warm backlighting of the lower drum’s exterior windows. Balustrade concealed 70W ceramic discharge metal halide lamps wash the upper drum, while recreations of original etched globes silhouette the portico columns.
The Capitol’s interior provided a wealth of opportunities for creative lighting restoration. Original lumimaires, whose identities were known only through archival photographs, were recreated by “harvesting” ornamental architectural castings from the surviving lighting fixtures. Metal work details were captured through a lost wax casting process allowing for new parts/pieces to be fabricated and used to assemble the original designs.
The surviving luminaire families yielded a wealth of decorative castings enabling the recreation of several of the Capitol’s previously extinct designs.
Fully dimmable, cove-concealed, UV-filtered T5HO uplights ceilings and restored murals throughout. The building’s ornamental architectural luminaries had to be adapted as principal functional sources. With over 30 different ceiling heights, optical needs varied widely by location.
Surmounting the technical challenges, eight interchangeable, multi-lamp (compact fluorescent and ceramic discharge metal halide) flexible reflector assemblies were designed to fit the majority of historic luminaires. Each assembly provided a unique upward distribution, directed spill light into the luminaire’s decorative glass, permitted fine-tuning of room illuminances, all while articulating the volume’s architectural detail. By fully concealing all of the modern sources, the original character and design of each fixture was retained.
The cut crystal luminaires of the ceremonial Gold Room provided concealment opportunities for miniature halogen uplights.
In the Chambers, supplemental illumination for nighttime conditions comes from a directional backlighting system above the lay-lights. New steel frames alongside each lay–light stage T5HO asymmetric fluorescent luminaries, cross-focused onto the lay-light’s diffusion film backing. Based on each Chamber’s needs, the fluorescent fixtures are dimmed to provide predetermined illuminances. Photocell-controlled dimming of the historic luminaires monitors and adjusts their luminances providing visual balance with the lay-light intensities.
The Rotunda is dramatically lit with layers of directional light. Oblique 70W ceramic discharge metal halide precision floodlights, concealed in the non-public whisper gallery, articulate the dome’s relief from its spring point, with the central grand chandelier floating below.
The completely restored 3,000 pound chandelier features induction lamp sources, which provide soft light for the historic glass shades, while concealed 70W ceramic discharge metal halide PAR lamps project light into the dome’s apex fresco. Lenses near the glass shades’ rims “siphon” light from the historic bowls’ uplight distribution and redirect to murals at the drum’s base.