Mona Lisa Smile--Da vinci code Revealed

For nearly 500 years, people have been gazing at Leonardo da Vinci's portrait of Mona Lisa with a sense of bafflement ~ first she is smiling; then the smile fades; a moment later it returns only to disappear again.
Now, scientists claim to have uncovered the secret of how da Vinci produced the optical effects that created Mona Lisa's enigmatic smile.
A team in Europe has found that the artist managed to achieve his trademark smoky effect, known as sfumato, on the painting by applying up to 40 layers of extremely thin glaze thought to have been smeared on with his fingers.
The glaze, mixed with subtly different pigments, creates the slight blurring and shadows around the mouth that give the Mona Lisa her barely noticeable smile that seems to disappear when looked at directly.
Using X-rays to study the painting, the scientists were able to see how the layers of glaze and paint had been built up to varying levels on different areas of the face, The Sunday Telegraph reported.
Courtesy :http://www.thestatesman.net