French scientists used X-ray fluorescence spectroscopy to analyze the Mona Lisa, discovering that Leonardo da Vinci employed a technique called "sfumato" using thin layers of manganese oxide or copper in the shadings to create depth and shadows. The total thickness of all the paint layers is less than 40 micrometers, about half the thickness of a human hair. The results of the analysis were published in a chemistry journal.

1. Instrumentation
Used to Analyze
Mona Lisa
Doland, A. French scientists crack secrets
of Mona Lisa. Associative Press, 2010.

2. X-Ray Fluorescence
Spectroscopy
Used to determine
thickness and element
analysis
Excites electron:
photoelectric effect
Based on wavelength
and intensity can
determine elements
and amounts present

3. What
Discovered?
The technique, called "sfumato,"
allowed da Vinci to give outlines
and contours a hazy quality and
create an illusion of depth and
shadow.
In the "Mona Lisa," da Vinci used
manganese oxide in his shadings.
In others, he used copper.
Added up, all the layers are less
than 40 micrometers, or about half
the thickness of a human hair
The results were published
Wednesday in AngewandteChemie
International Edition, a chemistry
journal