Relative modulation sensitivities of the red and green color mechanisms.

The sensitivities of the human green and red cone mechanisms to sinusiodally flickering light were found to be near equal and independent of field size and estimation method No wavelength dependency of modulation sensitivity was found. An observer who lacks the red cone pigment (protanope) did not show unusually high flicker sensitivity to green light of 525nm. The modulation transfer function for the normal observer measured with a green flickering test on a red background is identical to that on a green background when the backgrounds have been equated for the green cones by the protanope. The same is true for the contrast transfer function of the normal observer when determined with a green grating on the red and green backgrounds equated by the protanope.