Why does the woman depicted in the Mona Lisa appear to be both smiling and not smiling at the same time? The smile part of the Mona Lisa’s face was painted by Leonardo in low spatial frequencies. This means that when you look right at her mouth, there’s no smile. But if you look at her eyes or elsewhere in the portrait, your peripheral vision picks up the smile.
I’ve heard this before, but I’m posting this today because I recently read this great quote from Stanley Kubrick:
How could we possibly appreciate the Mona Lisa if Leonardo had written at the bottom of the canvas: ‘The lady is smiling because she is hiding a secret from her lover.’