Synchrotron-based high angle resolution and high lateral resolution X-ray diffraction reveals lead white pigment qualities in Old Masters paintings.

Microsamples collected on 27 major paintings by Old European Masters dating from the 14th to the late 19th centuries were analyzed using synchtotron-based X-ray diffraction. Two complementary analytical configurations were used at beamlines ID22 (high angle resolution) and ID21 (high lateral resolution), in order to highlight markers of the different grades of the lead white pigments (mixture of cerussite PbCO3 and hydrocerussite Pb-3(CO3)(2)(OH)(2)). Rietveld analysis and crystalline phases mapping at the microscale revealed the composition and microstructure of the pigments, shedding light on the preparation recipes and pigment choices of the artists through History.