Chromatic changes on the wall paintings in Sanderum Church (Denmark)

This paper describes observations and results of analyses undertaken to find explanations for several phenomena affecting the colours on the Gothic wall paintings in Sanderum Church (Denmark). Paintings have been exposed on four webs of the chancel vault and one web in the nave since 1882. Three additional webs have recently been uncovered, enabling a comparison of the new un-restored scenes with the previously restored scenes. A general weakening affecting all colours was observed on the newly exposed paintings due to the limewashing and uncovering process. In addition, specific deterioration phenomena affecting the black contour lines, copper pigments and red lead were examined. The study also focuses on the lack of confirmed binding medium in the colours. Scientific analyses were augmented with tests performed on dummy paintings and limewashed tiles.