The left part of this Gothic painting was unintentionally destroyed in 1971 by taking the plaster off the base, leaving a few thousand pieces of plaster in sizes ranging from one square decimeter to one-half square centimeter. A photograph, dating from before 1945, was used to produce a drawing which was put on the wall by epidiascope, and the ruined parts of the painting still attached to the plaster were glued in place with a solution of poly(vinyl acetate) and fine sand. Missing plaster was made up of lime and sand mortar and horizontally hatched with dry dyes and poly(vinyl alcohol).