Nuclear physicists have revealed that the work of Sicilian artist Antonello da Messina (1430–79) may have been ahead of its time. He was among the first, they suggest, to subtly refine the shading in his paintings by spotting them with lacquer. When applied to particular areas of a painting, this glaze, made from red pigment mixed with oil, enhances the impression of depth.

Credit: CIVIC MUS. ANCIENT ART, TURIN (COURTESY OF TURIN MUSEUM FOUNDATION)

Pier Andrea Mandò and his colleagues at the Italian National Institute of Nuclear Physics' Labec laboratory in Florence took advantage of the availability of Antonello's Portrait of a Man (1476) during its restoration this summer. They had already developed and used non-destructive PIXE (for 'particle-induced X-ray emission') scans to reconstruct the spatial distribution and concentration of chemical elements on the surface of some types of artistic work, such as gold laces and embroideries. They wanted to try the technique for the first time on a painting.

The physicists identified traces of aluminium and iron — a typical signature of lacquers — in tiny, uneven spots over the red cloak of the unknown subject. Although such glazes were already in use in the fifteenth century, they were normally applied with a brush over an entire surface. The scan reveals a weave-like imprint across the red cloak, suggesting to the restorers that here the shiny substance was dabbed on with a cloth.

Later, similar effects were created by great masters such as Leonardo da Vinci (1452–1519), who used his finger, and Rembrandt (1606–69), who used the end of his brush. But if Mandò and his colleagues are correct, it was Antonello — best known for introducing certain techniques of Flemish masters into Italy — who pioneered the effect.