Effects of relative area on matching heterochromatic stimuli for saturation

Participants adjusted the saturation of one rectangular color stimulus so that it appeared to match the saturation of another rectangular color stimulus for stimulus pairs of different relative areas. In Experiment 1, in which stimuli of complementary colors were used, higher saturation stimuli were consistently chosen for large areas to match lower saturation stimuli in smaller areas. In Experiment 2, better saturation matches were obtained if participants fixated and the stimuli were presented for very brief durations. In Experiment 3, larger color contrast effects were obtained with hue pairs that were nearer to complementary than with hue pairs that were more nearly the same. These findings agree with the interpretation that biases in relative saturation selected to match stimuli of different relative size are largely the result of negative afterimages of the larger stimulus having greater impact on the apparent saturation of the smaller stimulus.