3-D scan uncovers secrets behind Mona Lisa’s smile
The Mona Lisa has yielded some of her secrets to a 3-D research technique pioneered by Canada’s National Research Council, but Leonardo da Vinci’s sfumato painting technique remains a mystery.
The 3-D scanning technology has revealed more about what Mona Lisa was wearing than scientists have ever known before and that has given a clue into why she may be smiling.
Some of the equipment used to make a 3-D scan of the Mona Lisa to uncover secrets behind her smile.
(CBC)
Undetectable to the naked eye under the dark glaze is the translucent gauze garment over her dress called a guarnelo.
It was worn at that time by women who were pregnant or had just given birth, leading scientists to conclude that she sat for the painting shortly after the birth of her younger son.
That could account for the smile, but da Vinci’s secrets for creating such a beautiful work of art remain undetected.
The 16th-century artist called the technique he used to paint Mona Lisa sfumato. Art experts believe it involved painting several translucent layers of colour to create the appearance of depth.
The high-resolution 3-D laser scanning technology used by an NRC research team allows study of the layers of paint used, down to a micron in width (about one-tenth the width of a human hair).
But scientists still can’t tell how Leonardo achieved the uncanny detail of the Mona Lisa, or the effect of having her eyes follow the viewer.
The 11-person NRC team created a 3-D model of the painting by scanning the original — a technique that does no damage.
After examining the painting layer by layer, they found no signs of brush stroke detail, nor evidence that Leonardo used his fingers as he did in other works.
"It’s extremely thinly painted and extremely flat, and yet the details of the curls of hair, for example, are extremely distinct," John Taylor, co-ordinator of the research team, said in a news release on Tuesday.
"So the technique is unlike anything we’ve ever seen before. Leonardo was in a league of his own."
The NRC team visited the Louvre at the request of the Centre de recherche et de restauration des musées de France, which wanted confirmation that its preservation techniques for the masterpiece are the best available.
Although the work is seldom taken from its protected and climate-controlled setting, the researchers were given two nights to scan every aspect of the painting down to a micron’s width.
They created an archival quality 3-D digital model of the Mona Lisa, which they used to complete their study.
In good shape
After more than a year of analysis of the painting, they had some good news for the Louvre — current environmental conditions are likely to keep her smiling for years to come.
Researchers paid particular attention to a warp in the poplar wood panel Leonardo used to paint his work.
They discovered the panel is sensitive to changes in climate, but under its current storage conditions, there is no risk of degradation.
They also studied a 12-centimetre split on the top half of the painting, which probably dates from the 18th century, and decided it has not worsened over time.
The NRC scanning technique provided detailed analysis of the painting’s craquelure, the network of surface cracks.
"What our results show, and this corroborates the other studies, is that the paint layer itself, despite all its craquelure, is very well bonded to the poplar substrate," Taylor said.
"We didn’t see any sign of paint lifting. So for a 500-year-old painting it’s very good news. And if they continue to keep it the way they have in an environment-controlled chamber, it could remain like that for a very long time."
The results of the study are published in French in Au coeur de la Joconde by Les Éditions Gallimard and Mona Lisa: Inside the Painting, published in English by Harry N. Abrams Inc.
The 3-D technology used by the NRC is also being developed to make space exploration safer and allow more precise engineering on auto parts or other industrial applications.
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