Bezold Effect

From New World Encyclopedia
Demonstration of the Bezold Effect. The red seems lighter combined with the white, and darker combined with the black.

The Bezold Effect, also referred to as the "assimilation effect," is an optical illusion where a color's hue or value is affected by the color or colors surrounding it.


The Bezold effect was first discovered by a German professor of meteorology, Wilhelm von Bezold (1837-1907), who discovered that a color may appear different depending on its relation to adjacent colors. Bezold discovered that contrary to the already established finding of "simultaneous color contrast" in which a color takes on the complimentary hue and contrasting brightness of its surroundings, Bezold discovered that under certain circumstances a colored region will take on the same color as its surround.[1]


When looking at a specific hue, it can appear to change in appearance depending on the colors that surround it. For example, a yellow box surrounded by blue will look darker than a yellow box surrounded by red. Often, the surrounded color seems to take on a tint of the color that surrounds it; red boxes surrounded by blue will appear more bluish than those surrounded by white. The clearest demonstration is when two patches of identical color are surrounded by thin black and white borders respectively. The one surrounded by black appears darker than the one surrounded by white. The colored regions assimilate their border color; the opposite of the contrast effect often found with brightness, and also with hue.


The reasons behind the Bezold effect remain a neurological puzzle.[2] Although color interactions in the form of simultaneous color contrast effects could be explained by lateral inhibition and excitation functions in color perception, similar to in brightness perception, the assimilation in the Bezold effect is different. It is possible that spatial frequency factors dictate which effect, assimilation or contrast, will prevail.[1]


Knowledge of the Bezold effect is useful in fields such as graphic design, where artists can use combinations of adjacent colors to create the effect they desire.


  1. 1.0 1.1 Mark Fineman, The Nature of Visual Illusion (Dover Publications 1996 ISBN 0486291057)
  2. "Experiments with Spot 01" The Visual Perception Lab. Retrieved October 30, 2007.

ISBN links support NWE through referral fees

  • Albers, J. Interaction of color. Unabridged text and selected plates. 8 ed. Massachusetts: Yale University Press, 1978.
  • Fineman, Mark. The Nature of Visual Illusion. Dover Publications, 1996. ISBN 0486291057
  • Morioke, Noreen., Terry Stone., and Sean Adams. Color Design Workbook: A Real-World Guide to Using Color in Graphic Design. Lockport Publishers, 2006. ISBN 159253192X

External Links

All links retrieved October 1, 2023.


New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

The history of this article since it was imported to New World Encyclopedia:

Note: Some restrictions may apply to use of individual images which are separately licensed.