a blurred effect around the edges of highlight areas in a photographic image caused by reflection and scattering of light through the emulsion from the back surface of the film support or plate.
Origin of halation
First recorded in 1855–60; hal(o)
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for halation
Historical Examples of halation
Nor did the disturbing influence of the glare and halation of Kimberley only affect the vision of the diamond men within the town.
As at Sannah's Post, so again at Lindley the halation of a word or two in his orders fogged the image on his retina.
Halation is the term used to denote the spreading of light beyond its proper place on the negative.
The first advantage, which I soon discovered, is their entire freedom from halation.
British Dictionary definitions for halation
photog fogging usually seen as a bright ring surrounding a source of light: caused by reflection from the back of the film
Word Origin for halation
C19: from halo + -ation
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Blurring of the visual image due to glare from strong illumination.
A blurring or spreading of light around bright areas on a photographic image.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.