From Leonardo: The Last Supper

These photos show the disciple Matthew before (left), during (center) and after (right) the restoration. Working in patches, the restorers removed grime and blue-green overpainting from Matthew’s tunic, and muddy brown paint that covered his hair. The restorers discovered that much of the original blue paint of the tunic had been lost over the centuries, as is apparent in the final photo. They also found that Matthew’s lips were originally slightly parted in an expression of amazement.