When “digital media toolsmith” Øyvind Kolås posted his latest visual experiment to Patreon, little did he know that he’d get the internet buzzing. Kolås seemingly transformed a black and white photograph into full color with a simple trick to fool the eye. By placing an over-saturated color grid over a black and white image, he plays with the concept of color assimilation.

Color assimilation, also known as the Von Bezold spreading effect, occurs when our brain transfers perceived colors to its neighbors. The effect can be enhanced when there are areas of high contrast and the brain fills in the colors that it perceives should be present. In particular, Kolås was intrigued by Munker’s illusion, a type of color assimilation where horizontal stripes of different colors create the perception of different color tones.

“I came up with this illusion by experimenting with different patterns—and recently having worked on improvements for the saturation operation and being inspired by David Novick’s Munker illusions,” Kolås shares.

Kolås also experimented with the effect of using lines and dots.[…]

Source: Optical Illusion Makes People See Color When They Look at B&W Photos