Gilding of cultural heritage artefacts: an elaborated technology

Abstract

Gilding has been used to decorate, one may say sublimate, the surface appearance of artworks since the beginning of gold use in art. Gold foils and leaves were used first, thanks to the high ductility of that metal, and the progress of gilding art through centuries has been linked to: (1) the evolution of the thickness of the gold film used for the process; (2) the continuous research for efficient adhesive materials adapted to the various substrates; and (3) the development of techniques of direct adhesion of the gold coating, especially on metals. This paper, based on recent laboratory results obtained through laboratory studies of various museum artworks, discusses these three aspects. First, it shall develop a mechanical modelling of gold leaf beating. Second, it shall detail the properties of the main classes of adhesive materials used for leaf gilding on various materials. Finally, the importance of the diffusion phenomena at the interface between a metal substrate and a gold coating shall be discussed, especially in the case of gilding involving a high temperature treatment.