Yes, you’ve read the title correctly — this photo is not colored. It’s in black and white.
This optical illusion is made by digital media artist and software developer Øyvind Kolås as a visual experiment. Kolås calls the technique the “color assimilation grid illusion”.
...the technique… achieves its effect by simply laying a grid of selectively coloured lines over an original black-and-white image.
"An over-saturated coloured grid overlaid on a grayscale image causes the grayscale cells to be perceived as having colour," Kolås explains on his Patreon page.
So what’s happening here that makes our brains see this as a full-color image? Find out on Science Alert.
(Image Credit: Øyvind Kolås)
They do this in grocery stores with orange mesh bags for oranges. Oranges sold this way look ripe and sweet and good through the mesh, when they're not; they're dull and yellow and bitter, you wouldn't buy those otherwise. And you get used to it, so that one day you get a /real/ orange and you're stunned by how good it is.
That's not the only trick there. For example, next time you're in the produce section pick up anything of any color and watch it while you move it away from the bin; the color changes, becomes dull. They use special lighting to make fruit and vegetables look attractive. They can't afford to light the whole store with glamorous lights like that, but they don't have to; packages of things can be any color manufacturers choose.