The multi-layered structure of a traditional oil painting showing the support, glue, ground, preparatory, paint/glaze, and varnish layers. The complexity of the layered structure of the painting provides an added level of difficulty for researchers when studying the mechanical properties of paints and how they affect the overall stability of the painting. Painting information: Mary Cassatt, The Child’s Bath, 1893, Oil on canvas. The Art Institute of Chicago, Robert A. Waller Fund. Adapted from a figure in .