title: Field additivity of Stiles's Pi-4 color mechanism.
abstract: Stiles's middle-wave color mechanism Pi-4 is field additive for mixtures of 410-, 480-, 530-, 622-, and 670-nm adaptation fields, when studied with a 1-deg, 200-msec, 500-nm foveal test flash at 10 times absolute threshold.
mesh_terms: D000222:Adaptation, Physiological; D001696:Biomechanical Phenomena; D003118:Color Perception / Q000502:physiology*; D006801:Humans; D010775:Photic Stimulation; D012684:Sensory Thresholds; D014794:Visual Fields