The perception of surface blacks and whites.
D003118:Color Perception / Q000502:physiology; D005556:Form Perception / Q000502:physiology; D006801:Humans; D008029:Lighting; D012160:Retina / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*