Abstract
Abstract: :
Purpose: A coloured background may induce a contrasting colour in a figure viewed against it. We investigate whether chromatic contrast induction acts in the same way when the uniformly coloured surfaces traditionally used to demonstrate the effect are replaced by chromatically textured surfaces with the same space-averaged chromaticities and luminances. Methods: A method of sequential presentation is used to estimate the change in colour appearance induced by a background change. In each experimental trial, a 1-degree square figure of neutral chromaticity is presented for 0.5 seconds against a neutral background (30 x 20 degrees). Immediately afterwards, a test figure the same as the first but with a variable mean chromaticity, is presented for 0.5 seconds against a background whose chromaticity has been shifted in the direction of increasing L-cone excitation. During the top-up adaptation period, in which a uniform neutral background is displayed (minimum 1 sec), the observer indicates whether the second figure is 'redder' or 'greener' than the first. We determine the amount of L-cone contrast that must be added to the figure in the second presentation to make it appear the same colour as the neutral reference figure, as viewed in the first presentation. Results: Adding chromatic texture either to a figure or to its background reduces the background's influence on the figure's colour appearance. Yet the effect is markedly asymmetric: the contrast induced by a textured background on a uniform figure is significantly larger than the contrast induced by a uniform background on a textured figure. Conclusion: Colour appearance is strongly influenced by surface attributes, such as texture. This may explain why real-world objects do not generally change colour when set against different backgrounds.
Keywords: 360 color appearance/constancy • 597 texture • 362 color vision