Variability of color mixture data—II. The effect of viewing field size on the unit coordinates

Abstract

Theoretical sources of variation of published color mixture data with variation in field size were considered. The differences in unit coordinates for 2° and 10° fields may be explained by postulating that the effective optical density of the cone photopigments decreases as field size increases. 1.33° tritanopic coefficients and small-field (artificial) tritanopic coefficients are shown to be consistent with the density hypothesis. Effective optical density decreases exponentially as the centrally fixated field of view increases. Similar changes occur for fields placed at eccentric positions.