Perceived saturation in complex stimuli viewed in light and dark surrounds

Two similar complex targets, consisting of neutral patches ranging from white to black, were viewed, one in a dark surround and the other in an extended illuminated surround of 20% reflectance. Each target was viewed from a distance of three times its width, which is typical of picture viewing. The luminances of corresponding areas of the two targets were adjusted to produce equal apparent brightnesses and contrasts. Pairs of test colors of equal hues and apparent lightnesses and 2 degrees subtense were positioned successively within the pair of complex targets and were judged for relative color saturation. Under these conditions of equalized brightnesses, approximately the same purities were required for equal saturation in light-surround and dark-surround viewing conditions. These results, which differ from those reported for simple stimuli, are important in establishing aims for color reproduction.