What was the painter’s purpose in dissolving lead oxide in his oil paints? This recipe gives the paint used certain properties. “Lead oxide is a dryer that removes oil, [et donc à la peinture utilisée sur la Joconde] dry faster,” explains the chemist. Leonardo da Vinci probably used this recipe to give his paintings a different consistency. The material he took from his palette was more viscous and behaved differently on the board while saving drying time.
For a small painting like that of the Mona Lisa, “we can imagine that da Vinci bought his poplar wood panel unprepared and that by using this very special preparation layer he wanted the primer to dry quickly in order to be able to start work quickly.” explains Victor Gonzalez, taking up the idea of his colleague Elisabeth Ravaud, specialist in art history at the Ministry of Culture and Communication. “We can also imagine that he was looking for a specific visual representation,” he continues. The preparatory layer influences the upper layers, this is particularly true for the painting Belle Ferronnière, whose ground is orange.
This type of knowledge is essential to understanding the conservation of works. Having as complete an understanding of the chemical materiality of a color is the key to ensuring it can stand the test of time. “The Mona Lisa is a painting [n’a jamais été restauré] and that is very well preserved,” explains Gonzalez. Knowing the history of the chemical evolution of the compounds in a painting helps understand how best to preserve it and allows us to anticipate possible restoration efforts in the future.
It is probably not a secret recipe invented by Leonardo that would explain his genius. However, the evidence collected by scientists makes it possible to understand how techniques were passed down, especially from masters to students, during the Renaissance period. This transfer of techniques and knowledge is the breath of creative inspiration, but not its essence.
“Our discovery is a new piece of the puzzle for understanding an artist who was extremely complex in his materiality,” who experimented extensively and used a variety of techniques. This recipe, used by Leonardo da Vinci, is “not necessarily surprising for a Renaissance man,” Victor Gonzalez continues. It may be due to various influences that inspired or transmitted to the painter.
Nevertheless, it is a significant new reference for scholars and art historians, as it offers interesting study opportunities for understanding the circulation of Renaissance artistic and technological influences. The discoveries continue to surprise and complete an immense mosaic of information that contributes both to the historical and artistic field and to the preservation of cultural monuments.