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Mach bands

American  

noun

  1. an optical illusion in which adjacent bands of light and dark in a picture are perceived as much more contrasting than they really are.

Mach bands Scientific  
/ mäk /

  1. Illusory bands of intense lightness and darkness perceived adjacent to borders of light and dark in a visual image, caused by early image-processing in the retina and optic nerve.

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.