My lady Lisa, why do you smile so?
Are you amused, content, at peace?
More to the point, how did Leonardo da Vinci, who painted you 500 years ago, capture that enigmatic smile of yours for the ages?
A team of scientists from Canada's National Research Council has now created a 3-D digital model of the "Mona Lisa" -- a highly detailed computer scan of what may be the most famous painting in history.
They did it in 16 hours in a basement photo studio at the Louvre in Paris, where the painting is on display.
They have been poring over the results for nearly two years, and reported their first findings today.
They found that the wooden board on which da Vinci painted the portrait is slightly warped, but in surprisingly good shape, considering that the work was done between 1503 and 1506.
The oil paint is mottled with fine cracks, as happens to many old paintings, but the paint appears well-bonded to the wood beneath it.
Parts of the scan, done in X-rays and other wavelengths, show damage near the top of the painting, and a repair made after a visitor threw a stone at it in 1956.
Some of the paint near Lisa's right elbow is also an apparent attempt to repair earlier damage.
Keeping Her Secrets
Art historians are most curious to know how da Vinci created the painting's soft, slightly misty look.
The technique is known as "sfumato" -- borrowing from the Italian word for "smoke" -- and it adds to the painting's air of mystery.
So far, the researchers concede, da Vinci has kept his secrets.
They can tell he applied layers of translucent color on top of each other, something many other painters have tried to copy.
But just how did he do it?
Even with the laser scanner's power -- able to show details smaller than the width of a human hair -- they see no brush strokes, and none of da Vinci's fingerprints.
In other works of his, it is clear that he sometimes applied paint with his fingertips.
Most painters also leave clear evidence of brush strokes. Not da Vinci, and not on the "Mona Lisa."
The subject of the painting is said to be a young woman from Florence, Italy, named Lisa Gherardini, wife of a merchant named Francesco de Giocondo.
The "Mona Lisa" is sometimes known as "La Gioconda."
The Canadian researchers say they still have a great deal of work to do to interpret the data from their scan.
They have posted images from their work HERE.