Non-invasive on-site identification of colouring agents. Complementarity of mobile Raman and XRF spectroscopies
Résumé
Colored materials are the basis of many expressions of human craft, artistic and religious genius. The continuous miniaturization of radiation sources and detection systems for nearly 20 years has resulted in mobile instruments that perform close to that of laboratory devices. The constraints of on-site implementation and non-invasive use as well as the intrinsic weaknesses of mobile devices must be compensated for by establishing appropriate procedures. Taking as examples the analysis of enamelled objects, in particular those with sophisticated decoration (metal, glass or ceramic objects) and rock art paintings, we show the complementarity of Raman (µRaman) and X-ray fluorescence (pXRF) spectroscopies and present the procedures defined to identify the coloring agents and the crystalline or amorphous phases present in the colored layer and the substrate, this to document the objects (dating, state of conservation, authenticity) and exchanges routes between production and / or use centers .