Sky‐Blue Pink*

Abstract

ABSTRACTThe appearance of colours is affected by both instantaneous and gradual adaptations. Instantaneous adaptation can result in a projected white light looking both sky‐blue and pink when seen as shadows in superimposed orange and green light. Gradual adaptation can contribute markedly to the colour constancy of illuminants in the tungsten‐light to daylight range. In colour photographic reflection prints and projected transparencies, naming and scaling techniques have been used to determine the chromaticities of subjective grey‐points and preferred and acceptable reproductions of blue sky, green grass, and Caucasian skin. The use of haploscopic matching to determine, and Von Kries types of transformation to predict, equivalent stimuli for different adaptations is discussed: it is suggested that colour scaling is preferable to haploscopic matching because haploscopic results have been shown to be dependent on the matching technique adopted; it is also argued that, because adaptation cannot be adequately represented by a Von Kries type of transformation, equivalent stimuli are better defined by means of grids of lines of constant hue and saturation for various adaptation conditions.