French researches analyzed da Vinci's us of successive ultra thin layers of paint and glaze, which is a technique that gives his works their dreamy quality, reports CBS News
At the Center for Research and Restoration of the Museums of France, specialists found that da Vinci painted up to 30 layers of paint in his works. The layers add up to less than 40 micrometers, about half the thickness of a human hair. The technique is called "sfumato" and it allowed da Vinci to give outlines and contours a hazy type of quality, creating an illusion of depth of shadow. The French researchers used X-ray fluorescence spectroscopy, which is a noninvasive technique, to analyze the the chemical compositions and paint layers. This allowed the researchers to study the painting without having to actually take samples.
adds that the project was developed in collaboration with the European Synchrotron Radiation Facility in Grenoble.
Researcher Philippe Walter said that the analysis of the various paintings also shows da Vinci was constantly trying out new methods.
The results of the analysis have been published in an Angewandte Chemie International Edition, a chemistry journal.