The Early History of White’s Illusion

The illusion that is now commonly referred to as ‘White’s illusion’ involves changes in the lightness of the mid-grey test elements that replace sections of the black or white bars of a black–white square–wave grating. This paper describes the discovery of White’s illusion; an attempt to explain it in terms of assimilation theory; the interest it has generated amongst vision researchers; the subsequent discovery of dotted versions of the illusion; and the earlier discovery by other researchers of coloured versions.