The Tiffany dome in Preston Bradley Hall and the Healy & Millet dome in G.A.R. Rotunda were last repaired during two major campaigns in the 1940s and in 1977. In 2005, the center portions (each called an oculus) of both domes were restored during a pilot project to determine the condition of each dome, what would be required to restore them and how long the process would take. An examination of the Tiffany dome determined that 1,500 to 1,800 pieces of glass were cracked, and the glass was very dirty.
The pilot project also made a major discovery: Tiffany had included more than 6,000 rough chunks of clear glass, called jewels, in the panels to further catch and reflect light. During the first restoration, the glass panels were flipped over C for decades, the smooth sides of the panels faced into the room, while the jewels faced the exterior dome. This reconstruction of the panels once again faced the jewels into the room, as Tiffany intended, adding texture and sparkle to the space.
The Tiffany glass was restored by Botti Studio of Architectural Arts in Evanston. The Botti family has worked with glass since the 1600s in Italy, and many of the techniques still used in the studio are centuries old. The Botti staff began restoring the panels in January 2008. The panels were worked on a few at a time and progressed through the studio’s workstations, until each was completed and then crated for its return to the Chicago Cultural Center.
Click to view photos. Photos by Elizabeth Blazius.
The first step in restoring the glass was to “map” each panel. A tiny label with an identification number was placed on each piece of glass within a panel. Three sets of charcoal rubbings were made for each panel; the rubbing became the record of a panel and the blueprint for its accurate recreation. One set of rubbings was added to the project’s permanent archives, so that future curators of the dome will have records showing what was done in 2008. Information such as the number of each piece of glass, comments about it, and measurements of the thickness of the lead came between the pieces of glass were recorded on the rubbings. Photos were taken with and without background light shining through the glass.
Once a panel had been mapped, Botti’s staff would take it apart. Starting at a corner, the lead came was unwound from around each piece of glass. In turn, each piece was dipped into a solution of conservator’s soap, the same soap used to clean horses’ manes and tails, then cleaned with a soft wire brush and a razor blade to remove decades of encrusted putty and dirt. Cracked pieces were carefully glued together. Missing or mismatched pieces from previous repairs were replaced with new glass created specifically to match. When all the pieces of glass in a panel were ready, new lead came was wrapped around each piece.
Before reassembling a panel, the glazier referred to the rubbing in order to lay out the pieces correctly. Working on a thick wooden board, the bottom row of pieces was set into the channel of the lead came. Each row of pieces was placed next to the previous row. To hold them into place, flat-sided horseshoe nails were driven behind each row, until the panel can be bound with channel around all sides. The pieces were soldered together, making the panel whole again. Short pieces of copper wire were soldered onto the leading; they fit around a system of support bars, called “saddle bars.”
The Tiffany dome in Preston Bradley Hall and the Healy & Millet dome in G.A.R. Rotunda were last repaired during two major campaigns in the 1940s and in 1977. In 2005, the center portions (each called an oculus) of both domes were restored during a pilot project to determine the condition of each dome, what would be required to restore them and how long the process would take. An examination of the Tiffany dome determined that 1,500 to 1,800 pieces of glass were cracked, and the glass was very dirty. 
