We may never know who the Mona Lisa was or what she’s smiling about, but we do have some idea of how Leonardo da Vinci created the somber mood and smoky colors that add to her allure.
Leonardo painted on a variety of surfaces. He sometimes used wet plaster or sometimes painted on dry stone wall. He usually used hand-made oil paints, from ground pigments. Later in life he used tempura from eggwhites and worked on canvas, board, or, again, stone (if he was painting a mural).
As he began to paint, Leonardo would first create a detailed underpainting in a neutral gray or brown, then apply his colors in layer after layer of transparent glazes on top—using a limited range of tones. Some of the underpainting would show through the layers, subtly helping to create form. Creating colors by applying glazes also gives a painting a depth you cannot get by applying a color mixed on a palette.
According to Leonardo da Vinci biographer Walter Isaacson, this method also "allowed him to produce luminous tones. The light would pass through the layers and reflect back from the primer coat, making it seem as if the light was emanating from the figures and objects themselves."
On his palette were muted, earthy browns, greens, and blues within a narrow tonal range. This helped give a sense of unity to the elements in the painting. No intense colors or contrasts for him, so no bright red for Mona’s lips nor blue for her eyes (though it doesn't explain why she hasn't got eyebrows!).
Leonardo was a master at “chiaroscuro," an Italian term meaning “light/dark." This technique uses the contrasts of light and shadow "as a modeling technique for achieving the illusion of plasticity and three-dimensional volume," according to Isaacson. "Leonardo's version of the technique involved varying the darkness of a color by adding black pigments rather than making it a more saturated or richer hue.”
Soft, gentle lighting was crucial to his paintings. Facial features were not strongly defined or outlined but conveyed by soft, blended variations in tone and color. The further from the focus point of the painting, the darker and more monochromatic the shadows become.
Leonardo’s pioneering technique of softening colors and edges with dark glazes is known as sfumato, from the Italian fumo, meaning smoke. It’s as if all the edges have been obscured by a haze of transparent shadows, or smoke. According to Isaacson, this technique of "blurring contours and edges...is a way for artists to render objects as they appear to our eye rather than with sharp contours."
As Leonardo wrote in his Notebooks, "Your shadows and lights should be blended without lines or borders in the manner of smoke losing itself in the air.”
For a modern version of Leonardo’s palette, select a small range of transparent earthy colors whose midtones are similar, plus black and white. Some manufacturers produce a range of neutral grays ideal for a tonal underpainting.
Isaacson, Walter. Leonardo da Vinci. New York: Simon & Schuster, 2017
Nagel, Alexander. “Leonardo and Sfumato.” Anthropology and Aesthetics. 24 (Autumn, 1993): pp. 7-20.