THREE-DIMENSIONAL IMAGING OF PAINT LAYERS AND PAINT SUBSTRUCTURES WITH SYNCHROTRON RADIATION COMPUTED μ-LAMINOGRAPHY

Information on the creation of a painting lies usually hidden under the surface. A painting's substructure may include the underdrawing, underpainting, modifications to the initial setup (or pentimenti), and sometimes even abandoned compositions. Traditionally, the study of these characteristics relies on penetrative, two-dimensional imaging techniques (infrared reflectography, x-ray radiography) complemented with selected paint cross-sections. The limitations of this approach are twofold. First, it can be difficult to combine data from cross sections with two-dimensional images, because of poor redundancy of both methods. Second, cross sections involve destructive sampling of the paint layer. This paper introduces synchrotron radiation computed micro-laminography in the study of paintings. The technique allows for three-dimensional imaging of the paint stratigraphy in a nondestructive manner, enabling the imaging of paint layers, their interfaces, the ground, and carrier. The technique is demonstrated on a test painting, and its interest to curators and conservators of painting collections is discussed.