title: Multispectral camera and radiative transfer equation used to depict Leonardo's sfumato in Mona Lisa.
abstract: The technique used by Leonardo da Vinci to paint flesh tints--the sfumato--has never been scientifically depicted until now. From 100,000,000 reflectance spectra recorded on Mona Lisa, a virtual removal of the varnish is first obtained. A unique umber pigment is then identified in the upper layer and an exceptional maximum of the color saturation is underlined, both characteristics of a glaze technique. The modeling calling upon the radiative transfer equation confirms this maximum of saturation, the identification of an umber in the upper layer, and moreover underlines a mixture of 1% vermilion and 99% lead white in the base layer. Finally, the modeling, using the auxiliary function method, explains the spectacular maximum of saturation by the multiple scattering.
authors.affiliation: Institut des NanoSciences de Paris, Université Pierre et Marie Curie, Unité Mixte de Recherche 7588, Centre National de la Recherche Scientifique, Campus Boucicaut, Paris, France. elias@physique.univ-evry.fr
authors.forename: Mady
authors.initials: M
authors.lastname: Elias
authors.forename: Pascal
authors.initials: P
authors.lastname: Cotte