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.’

via kot­tke