That damn Coke can explained - Retinex or good old Color Constancy

In this video I demonstrate the Retinex effect (also known as Color Constancy) that causes colors to be perceived when they aren't there.
Fruit Bow by Ella Olsson via Flickr
flickr.com/photos/ellaolsson/...
Attribution 2.0 Generic (CC BY 2.0)
en.wikipedia.org/wiki/Color_c...

[@positivecrusader]

Nice explanation. What about the role of opposite colors? There's a lot of cyan in the Coke can photo, and it gets us to perceive the adjacent non-color areas as the opposite of cyan - red. If you go into Photoshop and shift the cyan toward yellow, you'll see that the Coke can now appears the opposite of yellow - purple.

[@warehouseeyes]

Exactly, I used PhotoShop to crop out the logo on the can and even turned it from a can into just a square shape, and it still looks red - because of the cyan background.

[@dutchdykefinger]

i inverted the colors and it turned into red on white.
then i made the can grayscale, and it was just a regular old grayscale
it kind of makes sense in reverse since cyan + red makes white.

[@niixx324]

With darker grey lines it does kinda look orange.