TypeLight and color
InteractiveYes: sliders and a check
First described1970
The red stripes on the left look pinker; on the right they look more orange. They are the same red.
Try this
- Tick Remove the stripes to see the reds match.
- Make the stripes wider with Stripe width: the effect changes.
Why it happens
With thin stripes, the red seems to blend toward the color of the stripes around it (assimilation), the opposite of the contrast you see with big patches. This version is related to the Munker-White illusion. Like White's illusion, the effect depends on how the brain groups the stripes, which Barton Anderson explained in terms of perceived transparency.
Did you know?
Assimilation is why mesh bags of oranges are orange and bags of lemons are yellow.
References
- Anderson B. (1997). A Theory of Illusory Lightness and Transparency in Monocular and Binocular Images: The Role of Contour Junctions. Perception, 26, 419-453. doi:10.1068/p260419
- White M. (1979). A New Effect of Pattern on Perceived Lightness. Perception, 8, 413-416. doi:10.1068/p080413
- Background on Wikipedia
The illusion on this page is drawn by code written for this site. Last checked 1 November 2026.
Frequently asked questions
Are the red stripes the same color?
Yes. Remove the stripes to check.
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Gray spots flicker at the crossings of the white streets, except where you look.