– French scientists from the National Center for Scientific Research (CNRS) revealed details hitherto unknown, associated with the technique of sfumato (disolve), used by Leonardo da Vinci in some of his greatest paintings, such as Mona Lisa.
In the sfumato, experts say, the lights and shadows are mixed with smoke and the strokes or contours are no longer appreciated.
The researchers conducted a quantitative chemical analysis of seven of Da Vinci’s works, that are at the Louvre Museum in Paris, through a noninvasive technique called X-ray fluorescence spectroscopy, which measures the thickness of the layers of paint and their chemical composition.
This study, which focused on the faces of the work shows that Da Vinci used different mixtures for shadows, which are characterized by a technique that uses layers of enamel, as well as various pigments and additives including manganese oxide, copper oxides and glazes, plus a transparent ink that was added to soften the tone of the painting.
In the case of enamels, the study discovered that the artist applied thin layers (between 1 and 2 micrometers to a thickness of 40 microns, half the thickness of a human hair) to achieve shades he desired. The superposition of enamels allowed the creation of depth and volume in the painting.