Spectroscopic investigations of Bourdichon miniatures: masterpieces of light and color.

Metallic bismuth, pyrite (FeS2), and specular hematite (Fe2O3) were found to have been used extensively on two miniatures taken from the Book of Hours of Louis XII by Jean Bourdichon, painter at the Royal Court of France between the end of the 15th and the beginning of the 16th centuries. These unusual materials were identified, together with thirteen other more traditional pigments and dyes, by Raman microscopy and X-ray fluorescence. Pyrite was found in many areas, suggesting that it may have been deliberately added as a pigment. The luminary quality of both miniatures was enhanced by the extensive use of shell gold throughout, but other less common materials such as specular hematite and mosaic gold were also utilized. Metallic bismuth was used, alone or in admixture with other pigments, to create a soft gray color. Its identification as a paint material was complemented by the study of the optical and visual properties of standard samples of metallic bismuth and several bismuth compounds. Evidence for the use of a bismuth pencil was also found.