Cite as:
Moreira H, Lillo J, 2004, "Lightness compression causes hue changes in Gelb chromatic staircases" Perception 33 ECVP Abstract Supplement

Lightness compression causes hue changes in Gelb chromatic staircases

H Moreira, J Lillo

Gelb illumination causes lightness compression (Cataliotti and Gilchrist, 1995 Perception & Psychophysics 57 125 - 135). On the other hand, (i) hue perception is modified by luminance (Bezold - Brücke effect), and (ii) the use of basic colour terms is constrained by surfaces lightness (Boyton and Olson, 1987 Colour Research and Application 12 94 - 105). We tested if lightness compression can affect hue perception and hue naming. In experiment 1, we replicated the Gelb staircase effect using a CRT calibrated monitor. Four experimental conditions were ran: (i) dark surround, (ii) non-adjacent white frame, (iii) Mondrian (luminance range = 30 : 1), and (iv) non-adjacent Mondrian. As expected, lightness compression was maximum for (i), but lightness constancy increased gradually from (ii), through (iv), to (iii). In experiments 2 and 3, chromatic staircases were presented. Lightness compression along with hue changes were obtained, supporting the idea that it is not luminance per se, but lightness, which is important for hue perception. The pattern of results seems to follow chromatic selectivity (Krauskopf et al, 1986 Vision Research 26 23 - 32): the matched reflectances for chromatic stimuli were systematically higher than what should be expected from the results obtained for achromatic stimuli.[Supported

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