French Scientists Crack Secrets Of da Vinci’s Mona Lisa

AP reports that French scientists from the Center for Research and Restoration of the Museums of France have cracked a few secrets of Leonardo da Vinci portraits including  “Mona Lisa.” French researchers found that da Vinci used a technique, called ‘sfumato.’  “He painted up to 30 layers of paint on his works to meet his standards of subtlety. Added up, all the layers are less than 40 micrometers, or about half the thickness of a human hair, researcher Philippe Walter said Friday.” Mona Lisa’s elusive smile, however, remains a mystery.