On-site analysis of Limoges enamels from sixteenth to nineteenth centuries: an attempt to differentiate between genuine artefacts and copies

摘要

A selection of 15 painted enamels, most of which belong to Limoges productions, from 1500 to 1900 A.D., has been studied on-site in the storage rooms of musée des Arts décoratifs in Paris. The Raman signatures of the transparent and/or opacified glass matrix are discussed and compared with those which were previously recorded on glazed pottery, enamelled and stained glasses as well as Chinese cloisonné enamels. Analysed enamels mostly belong to soda-lime-based glass. Three types of compositions such as soda-lime (fifteenth to sixteenth century), soda-rich (fifteenth, sixteenthineteenth centuries) and lead-potash-lime (sixteenth and nineteenth centuries) are identified on the basis of the Raman signature of the glaze according to the wavenumber maxima of the Si?O stretching and bending multiplets. The pigment signatures are similar to those recorded on ceramic glazes and glass enamels, which proves the similarity of the technologies. Cassiterite as an opacifier and hematite red and Naples yellow pigment variations give characteristic Raman signatures. The presence of lead arsenate as a pigment opacifier in nineteenth-century samples is confirmed. Attempts are made to establish tools for the differentiation between genuine artefacts and nineteenth-century restoration or fakes.