Leonardo da Vinci is famend to this present day for improvements in fields throughout the humanities and sciences. Now, new analyses printed within the Journal of the American Chemical Societypresent that his style for experimentation prolonged even to the bottom layers beneath his work. Surprisingly, samples from each the “Mona Lisa” and the “Final Supper” recommend that he experimented with lead(II) oxide, inflicting a uncommon compound referred to as plumbonacrite to kind under his artworks.
An aura of thriller has surrounded the paints and pigments in da Vinci’s studio, main scientists to scour his writings and art work to seek for clues. Many work from the early 1500s, together with the “Mona Lisa,” have been painted on picket panels that required a thick, “floor layer” of paint to be laid down earlier than art work was added. Scientists have discovered that whereas different artists sometimes used gesso, da Vinci experimented by laying down thick layers of lead white pigment and by infusing his oil with lead(II) oxide, an orange pigment that conferred particular drying properties to the paint above. He used an analogous method on the wall beneath the “Final Supper” — a departure from the standard, fresco method used on the time. To additional examine these distinctive layers, Victor Gonzalez and colleagues wished to use up to date, high-resolution analytical methods to small samples from these two work.
The staff carried out their analyses on a tiny, “microsample” beforehand obtained from a hidden nook of the “Mona Lisa,” in addition to 17 microsamples obtained from throughout the floor of the “Final Supper.” Utilizing X-ray diffraction and infrared spectroscopy methods, they decided that the bottom layers of those artworks not solely contained oil and lead white, but additionally a a lot rarer lead compound: plumbonacrite (Pb5(CO3)O(OH)2). This materials had not beforehand been detected in Italian Renaissance work, although it’d been present in later work by Rembrandt within the 1600s. Plumbonacrite is just secure beneath alkaline situations, suggesting that it shaped from a response between the oil and lead(II) oxide (PbO). Intact grains of PbO have been additionally present in a lot of the samples taken from the “Final Supper.”
Whereas painters have been identified so as to add lead oxides to pigments to assist them dry, the method has not been proved experimentally for work from da Vinci’s time. Actually, when the researchers searched by his writings, the one proof they discovered of PbO was in reference to pores and skin and hair treatments, regardless that it’s now identified to be fairly poisonous. Although he may not have written it down, these outcomes reveal that lead oxides should have had a spot on the previous grasp’s palette, and might need helped create the masterpieces we all know at the moment.