The interior of the Washington Monument has over 190 carved stone tablets set into the walls of the edifice, many of them dating from the 1850’s. Of these stones, at least 12 of them were originally gilded. The gilding was used on lettering and ornament, most of it incised into the stones. The stones are of varying materials ranging from petrified wood to marble to sandstone. The Gilders’ Studio was chosen to work with conservators from the National Park Service on the isolation and conservation of the original gilding as well as restoring 10 of the stones with new gold leaf.
General Condition of the Gilding:
The original layers of gold leaf and primers were in various stages of deterioration due primarily to infiltration of moisture from the exterior of the edifice. Combined with this was vandalism and regilding with materials not entirely appropriate for the conditions.
Consolidation and Isolation:
The stones were inspected and cleaned to remove staining and efflorescence as well as mineral salts produced by the wet conditions. The existing gold was examined microscopically to best match the original color and alloy. Loose and flaking layers of gold and primers were then removed. The remaining well adhered original layers of gold leaf and primers were isolated with a coat of Soluvar Matte varnish.
There were several different factors taken into consideration when determining the best method to use in restoration of the gilding. Foremost is the environment. Even though the stones are inside the Monument, they are subject to extremes of temperature and moisture infiltration. Combined with this is the need to make the gilding reversible, while preserving the original isolated layers. An exterior acrylic gilding system was chosen as the most suitable solution, providing durability and reversibility (with ammonia) while protecting the isolated traces of original gilding. The stones were gilded with different alloys of 23 and 23.5 karat leaf to most closely match the original colors. Toning was done on selected areas as needed.