Checker shadow illusion

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 labelled A appears to be a darker color than the area of the image labelled B. However, they are actually exactly the same color.

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

• Opening the illusion in a image editing program such as Microsoft Paint 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 Microsoft Paint or other image editing programs.
• Using a photometer

See also

• Chubb illusion
• Lilac chaser
• Psychophysics

References

1. ^ Adelson, Edward H. (2005). "Checkershadow Illusion". http://web.mit.edu/persci/people/adelson/checkershadow_illusion.html. Retrieved 2007-04-21. 
2. ^ http://web.mit.edu/persci/people/adelson/checker_more_evidence.html

External links

• A high resolution remake of the illusion
• Video proof
• Real-life Proof
• Explanation of the effect
• Illusion of colours
• Video animation
• Alternative animation of the illusion
• An interactive presentation of the effect
• An interactive click-and-drag demonstration of the effect