Unveiling the Enigma: Researchers Identify Harmful Lead Compounds in Leonardo da Vinci’s Artistic Creations

New research underscores Leonardo da Vinci’s avant-garde application of lead(II) oxide in the foundational strata of his art, particularly in works such as the “Mona Lisa” and the “Last Supper,” which may have contributed to the enduring allure of these celebrated pieces.

Known for his groundbreaking contributions across both the arts and sciences, Leonardo da Vinci’s pioneering tendencies are now found to reach even to the substrates of his paintings. Fresh findings, reported in the Journal of the American Chemical Society, indicate that da Vinci utilized lead(II) oxide in the creation of a rare substance known as plumbonacrite beneath the surfaces of both the “Mona Lisa” and the “Last Supper.”

Da Vinci’s Enigmatic Choices of Paints and Pigments

Da Vinci’s choices in the realm of paints and pigments have always engendered a sense of mystique, prompting scientific exploration of his art and writings to uncover insights. Notably, many works from the early 16th century, such as the “Mona Lisa,” were executed on wooden panels, demanding an initial, substantial layer of paint. Unlike his contemporaries, who usually used gesso for this purpose, da Vinci opted for heavy layers of lead white and oil imbued with lead(II) oxide, thereby imparting unique drying properties to the overlaying paint.

A minuscule paint chip from the “Mona Lisa” has shed light on previously undisclosed facets of the artist’s methodology. Credit: Adapted from the Journal of the American Chemical Society, 2023, DOI: 10.1021/jacs.3c07000

For the “Last Supper,” da Vinci similarly deviated from conventional fresco techniques, choosing instead to use this unique foundational layer. To delve deeper into these extraordinary choices, Victor Gonzalez and his research team applied contemporary, high-resolution analytical methods to small samples procured from these artworks.

Comprehensive Examination and Results

The researchers executed their tests on an isolated “microsample” from a concealed corner of the “Mona Lisa,” as well as 17 microsamples from the “Last Supper.” Employing X-ray diffraction and infrared spectroscopy, they concluded that the ground layers not only incorporated oil and lead white but also contained an exceedingly uncommon lead compound: plumbonacrite (Pb5(CO3)O(OH)2).

This particular compound had never been previously identified in Italian Renaissance art, although it was later found in works by Rembrandt in the 17th century. Plumbonacrite is stable only in alkaline environments, which implies it likely emerged from a reaction between the oil and lead(II) oxide (PbO). Intact PbO granules were predominantly present in samples from the “Last Supper.”

Da Vinci’s Unorthodox Employment of Lead Oxides

Although it was not uncommon for painters to include lead oxides to expedite drying of pigments, no empirical evidence to date had verified this practice in works from da Vinci’s era. Examination of his extant manuscripts yielded references to PbO only in the context of skin and hair treatments, notwithstanding its contemporary understanding as a hazardous substance. Despite the absence of written documentation, the research attests to the likelihood that lead oxides were integral to da Vinci’s artistic techniques, potentially shaping the masterworks we venerate today.

Reference: “X-ray and Infrared Microanalyses of Mona Lisa’s Ground Layer and Significance Regarding Leonardo da Vinci’s Palette” by Victor Gonzalez, Gilles Wallez, Elisabeth Ravaud, Myriam Eveno, Ida Fazlic, Tiphaine Fabris, Austin Nevin, Thomas Calligaro, Michel Menu, Vincent Delieuvin, and Marine Cotte, published on October 11, 2023, in the Journal of the American Chemical Society.
DOI: 10.1021/jacs.3c07000

The authors express their gratitude for financial support received from the European Union’s Horizon 2020 research and innovation initiative, under the auspices of the Marie Skłodowska-Curie actions.

Frequently Asked Questions (FAQs) about da Vinci Lead Oxide Technique

More about da Vinci Lead Oxide Technique

• Journal of the American Chemical Society – The source where the research findings regarding da Vinci’s use of lead(II) oxide were published.
• Leonardo da Vinci – A comprehensive resource on the life and works of Leonardo da Vinci.
• Plumbonacrite – Detailed information about the chemical compound plumbonacrite.
• Italian Renaissance Art – An overview of the Italian Renaissance art movement, providing context for da Vinci’s work.
• Lead Poisoning – Information on the health risks associated with lead exposure, including lead(II) oxide, as referenced in the FAQ.