The X-radiograph
This is a detail of an x-radiograph of
Bouts' The Virgin and Child. After
being developed, the X-ray films are
used for study. Some pigments,
including lead white and lead-tin
yellow, contain elements of high
atomic weight. These colors will absorb
X-rays, will locally block
the blackening of the film, and will
appear as light areas in the X-radiograph.

Here, lead white was locally applied in the undermodeling of the Virgin's face, on the ridge of the nose, on the upper lip, and in the eye sockets. Other pigments and cracks absorbed the X-rays to a lesser extent, and thus appear dark on the X-radiograph.


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