Conservation of the St. Vitus Mosaic in Prague (1992-2003)
 

The central panel of The Last Judgment mosaic before cleaning. It is located on the exterior of St. Vitus Cathedral in the heart of Prague Castle. Photos: Dusan Stulik.

The central panel of The Last Judgment mosaic after cleaning. Photos: Dusan Stulik.

The central panel of The Last Judgment mosaic after regilding. Photos: Dusan Stulik.

Conservators apply coating on central panel of The Last Judgment mosaic in Prague. Photo: Eric Bescher.

Conservators on a cherry picker examine The Last Judgment mosaic at St. Vitus Cathedral, Prague Castle, while a television crew documents them. Photo: Neville Agnew.

Detail of the central panel after coating is applied to The Last Judgement mosaic. Photo: Eric Bescher.

The mosaic is cleaned prior to application of the sol-gel protective coating. After extensive studies and testing, the cleaning method selected was one using a stream of compressed air and microscopic glass particles. The use of such particles, which are harder than the corrosion layer but softer than the mosaic tesserae, thoroughly removed the corrosion layer without effecting the glass surface. Photo: Dusan Stulik.

The Charles Bridge, constructed in the 14th century by Emperor Charles IV, spans the Vltava River. On Hradcany Hill above the river, St. Vitus Cathedral towers over the walls of Prague Castle. Photo: Guillermo Aldana.