title: Spatial dependence of color assimilation by the watercolor effect.
abstract: Color assimilation with bichromatic contours was quantified for spatial extents ranging from von Bezold-type color assimilation to the watercolor effect. The magnitude and direction of assimilative hue change was measured as a function of the width of a rectangular stimulus. Assimilation was quantified by hue cancellation. Large hue shifts were required to null the color of stimuli < or = 9.3 min of arc in width, with an exponential decrease for stimuli increasing up to 7.4 deg. When stimuli were viewed through an achromatizing lens, the magnitude of the assimilation effect was reduced for narrow stimuli, but not for wide ones. These results demonstrate that chromatic aberration may account, in part, for color assimilation over small, but not large, surface areas.
authors.affiliation: Section of Neurobiology, Physiology and Behavior, Department of Ophthalmology and Vision Science, University of California, Davis, 4860 Y Street, Suite 2400, Sacramento, CA 95817, USA. Frederic.Devinck@psychol.uni-giessen.de
authors.forename: Frédéric
authors.initials: F
authors.lastname: Devinck
authors.forename: Peter B
authors.initials: PB
authors.lastname: Delahunt
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Hardy
authors.forename: Lothar
authors.initials: L
authors.lastname: Spillmann
authors.forename: John S
authors.initials: JS
authors.lastname: Werner
mesh_terms: D003118:Color Perception; D015350:Contrast Sensitivity; D003623:Dark Adaptation; D006801:Humans; D008027:Light; D008960:Models, Psychological; D010775:Photic Stimulation / Q000379:methods; D011581:Psychological Tests; D011601:Psychophysics; D015348:Vision, Binocular; D015349:Vision, Monocular