The Collaborative International Dictionary
Halation \Ha*la"tion\ (h[asl]*l[=a]"sh[u^]n), n. (Photog.) An appearance as of a halo of light, surrounding the edges of dark objects in a photographic picture.
Wiktionary
n. 1 The action of light surrounding some object as if making a halo. 2 The blurring of light around a bright area of a photographic image, or on a television screen.
Usage examples of "halation".
Since the linen worn before the camera is dyed a faint tint to prevent the halation caused by pure white, it was a sure sign to me that he had spruced up a bit.
Chinese yellow is used largely in studios in place of white in make-up because it does not cause halation, which, to the picture people, is the bane of their existence.
He tried to alter their course, to lunge aside, but the current proved irresistible and he was borne into the golden halation, then to within inches of the woman’s grasping fingers.
On each in halation you say three words very slowly and distinctly inside your head.