Conservation of a Chinese gu at the Canadian Conservation Institute

Abstract

Conservation and technical issues pertaining to the investigation of six mediaeval Spanish ceramic lustre fragments are reported. Assessment of methods and materials to replicate the lustre glazes indicates that the spray application of nacreous (pearlescent) pigments in combination with conventional inorganic pigments and transparent colorants in an acrylic lacquer gives good results. The salient optical features oflustre glazes and nacreous pigments are discussed. Scanning electron microscopy in conjunction with electron diffraction studies are employed to characterize the glaze and ceramic body composition of the fragments. Transmission electron microscopy indicates that a uniform dispersion of copper crystallites, c. 2-4nm in diameter, is responsible for the lustre effect in one sherd.