By using X-rays to study the chemical structure of a tiny dot in the famous artwork, scientists have gained new insight into the techniques Leonardo da Vinci used to paint his groundbreaking portrait of the Woman with the Enigmatic Smile.
The study, published Wednesday in the Journal of the American Chemical Society, suggests that the famous Italian Renaissance master, curious, learned and inventive, may have been in a particularly experimental mood when he began work on “The Mona Lisa.” began at the beginning of the 16th century.
The oil paint recipe that Leonardo da Vinci used as a base coat to create the poplar wood panel appears to have been different for the “Mona Lisa,” with its own distinctive chemical signature, the team of scientists and art historians in France and Britain have found.
“He was someone who liked to experiment, and each of his paintings is completely different on a technical level,” explained Victor Gonzalez, lead author of the study and a chemist at the National Center for Scientific Research (CNRS), France’s largest research organization. Mr. Gonzalez has studied the chemical composition of dozens of works by Leonardo da Vinci, Rembrandt and other artists.
“[Léonard de Vinci] was a person who loved to experiment and each of his paintings is completely different on a technical level.”
-Victor González
“In this case, it’s interesting to see that there is actually a special technique for the base layer of ‘Mona Lisa,'” he said in an interview with the Associated Press.
Specifically, the researchers found a rare compound, leadonacrit, in the first layer of paint. According to Mr. Gonzalez, this discovery confirmed for the first time what art historians had previously only suspected: that the artist most likely used lead oxide powder to thicken and dry his paint when he began work on the famous portrait exhibited at the Louvre Museum in Paris .
An important discovery
Carmen Bambach, a specialist in Italian art and curator at the Metropolitan Museum of Art in New York, who was not involved in the study, called the research “very exciting.” She said any new scientific understanding of Leonardo da Vinci’s painting techniques was “extremely important news for the art world and our global society as a whole.”
The discovery of plumbonacrite in “The Mona Lisa” testifies to “Leonardo da Vinci’s passionate and constant experimental spirit as a painter – that makes him timeless and modern,” Bambach argued via email.
The analyzed painting fragment was barely visible to the naked eye, no larger than the diameter of a human hair, and came from the upper right edge of the painting.
Scientists studied its atomic structure using X-rays in a synchrotron, a large machine that accelerates particles to near the speed of light. This allowed them to discover the chemical composition of the grain. Plumbonacrite is a byproduct of lead oxide, so researchers can say with greater certainty that the painter likely used this powder in his paint recipe.
“Plumonacrite is really a fingerprint of his recipe,” Mr. Gonzalez said. This is the first time we can actually confirm it chemically.”
A recipe used by others
According to Leonardo da Vinci, the Dutch master Rembrandt may have used a similar recipe when he painted in the 17th century; Mr. Gonzalez and other researchers have also already found plumbonacrite in his work.
“It also shows us that these recipes have been passed down through the centuries,” he noted. It was a very good recipe.”
It is believed that Leonardo da Vinci dissolved orange lead oxide powder in linseed or walnut oil by heating the mixture to create a thicker, quicker-drying paste.
“You get an oil that has a very nice golden color,” Mr. Gonzalez said. It flows more like honey.”
But “The Mona Lisa” – which the Louvre believes is a portrait of Lisa Gherardini, the wife of a Florentine silk merchant – and other works by Leonardo da Vinci have other secrets to tell.
“There is certainly a lot more to discover. We’re barely scratching the surface,” Mr. Gonzalez said.
“What we say is just another small piece of knowledge.”