mona lisa

Hidden behind the Mona Lisa's enigmatic smile are dozens and dozens of layers of ultra-thin glaze, according to French researchers who examined the masterpiece through non-invasive X-ray fluorescence spectroscopy.

The investigation revealed that up to 40 layers of transparent glaze, possibly smeared on with the master's fingers, produced the unique effect which is behind the lady's mysterious smile. --excerpt taken from Rossella Lorenzi