(a) Johannes Vermeer’s painting Girl with the Red Hat, c.1669. (b) Infrared false-color image (rotated 180 degrees) showing some of the underpaint of an earlier painting of a man in a black hat obtained from reflectance imaging spectroscopy. (c) The optimized lead map (rotated 180 degrees) showing the use of mainly lead white in the painting of a man in a black hat obtained using X-ray fluorescence imaging spectroscopy.