Temporal properties of brightness and color induction.

With a matching procedure, we studied the temporal properties of direct brightness (or lightness) and chromatic changes (produced by modulation of the region being matched) and induced brightness and chromatic changes (produced by modulation of the surround of the region being matched). The amount of direct brightness and color change was found to vary only slightly with temporal frequency over the 0.5-8 Hz range studied, whereas induced changes were found to occur only at low temporal frequencies, below about 2.5 Hz. With high temporal-frequency modulation of the surround, the induced patterns appeared to flicker but not to change in brightness or color. Despite the fact that chrominance and luminance temporal contrast sensitivity functions are very different, the temporal induction curves for color and brightness were very similar. However, brightness induction was found to increase approximately linearly with increasing surround modulation up to very high levels, whereas the amount of color induction was much less dependent on the modulation depth of the surround.