Is there a relationship between art and science? You might say, whereas an artist focuses on aesthetics, a scientist is immersed in numbers and mathematical equations. From my perspective, both art and science have many commonalities: creativity, imagination, curiosity, perseverance, and you can add more. Art and Science are as different as day and night. But there are shadows of day and night flowing into one another at their edges, and the art and science connection is the same.
The Mona Lisa is an excellent example of where art and science come together. The painting is considered to be the masterpiece of Leonardo di ser Piero da Vinci, although he never finished it as he always did with other works. Mona Lisa is known for her mystic smile. When we look at the painting, the gradation of colors from dark to light is barely perceptible. Neither brushstroke nor contour is visible: It looks as though lights and shades are blended in the manner of smoke. How did Leonardo obtain such lively effects? It is definitely not an art- by- accident.
While the picture has been a center of attraction for art historians for centuries, understanding how Leonardo attained his perfection was nonetheless a challenge without sophisticated technology. A team of research scientists at the Louvre, led by Phillipe Walter, have recently investigated 9 paintings by Leonardo, including the Mona Lisa, using x-ray fluorescence spectroscopy (XRF)—and have found the secret behind Mona Lisa’s captivating smile. What gives the picture such fascination is the technique, so called sfumato (from the Italian for “shade” or” vanish”), that Leonardo mastered. It is comparable to “low contrast” techniques in photography. In this method, several layers of dark and light colors are applied over each other, which then blend together to impart the face with a mysterious glow.
In x-ray fluorescence spectroscopy, the paintings are exposed to x-rays, and each chemical element in the pigments gives off fluorescence at unique wavelengths (color). Then the elements can be quantified and the composition of the pigments, binders and the thickness of the paint layers can be determined. As XRF is a non-destructive technique, the composition and layer thickness can be analyzed without taking samples from the precious artwork. Previous investigations examined all the layers together. This time, state-of the- art high resolution XRF in combination with high-tech computer models allowed the scientists to analyze the paintings for their layer- by- layer composition . The studies bring out the stunning expertise of Leonardo da Vinci.
Manganese based pigment is used in the glaze, particularly in the Mona Lisa. While 2-5 micron thin glaze layers created lighter areas, the darkest shadows required thick layers of glaze. The thinness of the lighter layers detected shows the dexterity required for the artist’s amazing feat. Several days of drying time for each layer required Leonardo to toil for 4 years on the Mona Lisa painting, and he died with it still unfinished. In those paintings before Mona Lisa, he seems to have used a covering layer – dark pigments in the classic oil technique to attain the shade effect. In 40 years of work, Leonardo constantly researched ways to improve his visual effects of his art. In his later paintings, he took advantage of the dark pigments, rich in organic medium, to create a translucent effect.
Art and Science are the two sides of a coin. As novelist Vladimir Nabokov said, “There is no art without fact and no science without fancy.”