Materials surface science applied to the investigation of cultural heritage artifacts
Résumé
The knowledge and skill of ancient artisans in manufacturing artistic, ornamental or everyday useful artworks surprises the modern material scientists every time they investigate those objects. The use of sophisticated investigation instruments appears necessary to understand and appreciate the elaboration steps. The present conference will show, through the study of various museum and archaeological pieces, how the use of laboratory research instruments enlightens the processes used for the fabrication of unique items at periods as early as antic Egypt, Roman Empire and beginning of the Islamic era. A discussion will be first developed about the specificity of the use of surface science research instruments for investigations on museum objects. The absolute necessity to favour, and sometimes be limited to, non-destructive or non-invasive means will be emphasised and discussed. The examples chosen will concern: the application of nanostructured layers on the surface of ceramics to obtain the so-called lustred ceramics, invented by the Islam potters during the 8th century AD and still fabricated in western world since the Renaissance; the surface intentional coloration of metallic objects by chemical patination, attested in Egypt during the 2nd millenary BC and still applied by the Japanese traditional metal artisans; the history of gilding many kinds of decorative objects, using different procedure as leaf gilding (already in antic Egypt), mercury gilding (already in Roman Empire), and other processes; the Fresco technique, a unique and very perennial wall painting technique, known by the ancient Roman painter and also propagated through the centuries. All those examples open new investigation fields belonging fully to the modern materials science, in order to understand the mechanism involved in every processes with evidently the constraint that one does not know precisely all the detailed steps of fabrication. This is an exciting challenge.