The famous Mona Lisa's smile has been commented on, speculated about and discussed adnauseum, but now British researchers may have finally found the answer to the question of why she smiles when viewed at one angle and not at others.
The Mona Lisa, a portrait of a Milanese nobleman’s daughter painted by Leonardo da Vinci, is one of the most famous paintings in the world. There has always been mystery as to why when one looks at the painting, focusing on the subject's eyes, the lips appear to slant upwards in what has been described as a "tentative" and "enigmatic" smile, but when one looks at the mouth directly, they appear flatter.
Researchers from Sheffield Hallam University say the have solved the mystery of the smile by cross analysing the Mona Lisa with La Bella Principessa, another recently discovered da Vinci painting.
The team found "intriguing clues" as to how the Renaissance artist painted the Mona Lisa.
They believe that in both paintings, the same effect was achieved by a painting technique called “sfumato”, in which subtle shades and colors around the mouth of the subjects deliver a clever optical illusion, exploiting differences between peripheral vision and direct sight.
The researchers added another description to the smile, calling it “uncatchable.”
They organized several experiments in which viewers were asked to look at the Mona Lisa and La Bella Principessa from different angles and distances. The viewers were also shown digital copies of the paintings, blurred to different degrees.
The blurring copied the effects of peripheral vision, where objects are seen less distinctly. The more blurred the images were, the more the paintings subjects looked to be smiling.
In a paper published by the researchers, they said “La Bella Principessa’s mouth appears to change slant depending on both the viewing distance and the level of blur applied to a digital version of the portrait. It was found that a perceived change in the slant of La Bella Principessa’s mouth influences her expression of contentment.”
The researchers also viewed images of the two women with their eyes or mouths blacked out. In the images with the mouths blackened, viewers said that they couldn't discern any changes in expression which suggested the key lay with how the lips were painted.
Da Vinci painted La Bella Principessa before the Mona Lisa. It had long been believed the earlier painting was the work of a German artist from the early 19th-century, but recently it was attributed to da Vinci and thus enabled the groundbreaking research into one of art’s most enduring mysteries.