Raman identification of pigments and opacifiers: II. Arsenic‐based opacifiers/relation with Co ores

What is it about?

Raman analysis is a noninvasive technique that can be conducted on-site via a mobile system. However, the presence in variable quantity of different crystalline or amorphous phases (glassy matrix, opacifiers and pigments) in the enamel leads to the partial observation of Raman signatures, signatures often not being characterized in the literature. We study here the phases observed in the white, blue and yellow/green enamels of French and Chinese objects from the 18th century and compare the effectiveness of a solid-state spectroscopic approach (identification of the parameters determining the vibrational modes in relation to the structures) and the multivariate chemometric approach (PCA and Hierarchical Clustering), carried out on the global or partial spectra, or on the parameters extracted from the first approach.

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