Checker shadow illusion

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The checker shadow illusion is an optical illusion published by Edward H. Adelson, Professor of Vision Science at MIT in 1995.[1] The image depicts a checkerboard with light and dark squares. The optical illusion is that the area of the image labeled A appears to be a darker color than the area of the image labeled B. However, they are actually exactly the same color.

This can be proven using the following methods:[2]

  • Opening the illusion in an image editing program and using the eyedropper tool to verify that the colors are the same
  • Isolating the squares. Without the surrounding context, the effect of the illusion is dispelled. This can be done by using the selection tool in some image editing programs.
  • Using a photometer
  • Connecting the squares with a rectangle of the same color, as seen below in the middle figure.
Areas of the image A and B are the same color
A rectangle of the same color has been drawn connecting the two areas of the image

See also[edit]


  1. ^ Adelson, Edward H. (2005). "Checkershadow Illusion". Retrieved 2007-04-21. 
  2. ^

External links[edit]