An aftereffect of color which depends on the orientation of lines in the test field may be obtained by presenting a horizontal grating of one color alternately with a vertical grating of a different color. Like the aftereffect of adaptation to chromatic fringes produced by prismatic spectacles, this aftereffect is visible in monochromatic light and fails to show inter-ocular transfer. It is suggested that both effects are to be understood in terms of color adaptation of orientation-specific edge-detectors.