Rod Origin of Prolonged Afterimages

Science  27 Sep 1974:
Vol. 185, Issue 4157, pp. 1171-1172
DOI: 10.1126/science.185.4157.1171


Afterimages fade against any unchanging background but generally reappear if the background changes suddenly. Under some conditions, however, a change of background color fails to revive a faded afterimage. This happens only if the interchanged backgrounds equally stimulate the rod receptors. It follows that afterimages seen under these conditions are generated by rods.