JOIN USDa Vinci's paintings fascinate, partly due to a range of subtle optical effects that blur outlines, soften transitions and blend shadows, reports the journal Angewandte Chemie International Edition.
Known as "sfumato", this technique is not only the result of the genius of the artist but also of technical innovations at the beginning of the 16th century.
Scientists used a technique called X-ray fluorescence, to determine the composition and thickness of each layer in the paintings (including Mona Lisa's) of Da Vinci, made through the 40 years of his career.
Scientists have also found different recipes used by Da Vinci to do the shadows on the faces, according to a Laboratoire du Centre de Recherche statement.
These recipes are characterised by a technique (the use of glaze layers or a very thin paint) and by the nature of the pigments or additives.
In the case of glazes, thin layers of one to two micrometres (a micrometre is a millionth of a metre) were applied to obtain a total thickness of no more than 30 to 40 micrometres.
The study was led by the team of Philippe Walter, Laboratoire du Centre de Recherche et de Restauration des Musées de France, in collaboration with the European Synchrotron Radiation Facility and the support of Louvre Museum.