Shedding light on the colours of medieval alabaster sculptures: Scientific analysis and digital reconstruction of their original polychromy

Abstract

AbstractAlthough medieval alabaster sculptures might appear white at present, they were colourful once, because painting and gilding the stone was an integral part of their production. This work presents the study of polychrome remnants on a selection of fourteenth century English alabasters, using multiple scientific methods (microscopy, spectroscopic and chromatographic techniques). The range of pigments identified include vermilion, red ochre, red lead, kermes, verdigris, copper resinate, azurite, lead white and carbon black. Some sophisticated decorative techniques were also observed, namely the application of translucent glazes on top of raised gilded motifs. The analysis was useful in understanding the degradation processes undergone by some materials, such as verdigris. The use of oil as binding medium for the application of the paint layers and a mordant gilding technique were determined. These findings yielded important clues towards the digital reconstruction of the original appearance of the polychrome surface, which is also presented here.