Observer differences in color-mixture functions studied by means of a pair of metameric grays

The Granville metameri c gray p anels have served to characterize t he color vis ion of obser vers in a n approximate bu t useful way. Thus, t he 39 observers st udied, an d t he four color-m ixture fun ctions were classed into fi ve groups according to t he ir indica ted amoun ts of ocular pigmen tation. These pa nels were also used to measure t he correlation of lens a nd macular pigmentations wi th observer age, sex, a nd eye and ha ir colors. Of the three sets of color-m ixture fu nctio!ls inte nded to refer to 2° fi eld obser vat ion, t he 1931 Co mmission Interna tiona le de L 'Eclairage standard observer agrees best. _These data thus afford no basis for supplan t ing t he 1931 Commission Internat ionale de L' Ecla irage standard observer wi t h either t he J udd" i" or t he 1955 Stiles' 2° color-mixture t unctio n . The 1955 Stiles' 10° functions, however, agree fa irly well.