Rembrandt’s impasto deciphered via identification of unusual plumbonacrite by multi‐modal Synchrotron X‐ray Diffraction

Rembrandt (1606-1669) is renowned for his impasto technique, involving his use of lead white paint with outstanding rheological properties offering some 3D modeling possibilities. This was obtained by combining lead white pigment (a mixture of cerussite PbCO3, and hydrocerussite Pb3(CO3)2(OH)2) with an organic binding medium, but the exact formulation used by Rembrandt remains a mystery. A powerful combination of high-angle and high-lateral resolution X-ray diffraction was used to investigate several microscopic paint samples from four Rembrandt masterpieces. A rare lead compound, plumbonacrite, Pb5(CO3)3O(OH)2, was detected in areas of impasto. This constitutes the fingerprint of Rembrandt’s recipe and the evidence of the use of an alkaline binding medium which sheds a new light on Rembrandt’s pictorial technique.