TOWARD A MORE ACCURATE AND EXTENSIBLE COLORIMETRY - PART-V - TESTING VISUALLY MATCHING PAIRS OF LIGHTS FOR POSSIBLE ROD PARTICIPATION ON THE AGUILAR-STILES MODEL

The spectral power distributions of strongly metameric visually matchi ng pairs of lights, at visual fields of 10 degrees and 1.3 degrees and luminances front 0.2-120 cd/m(2), are examined for possible rod parti cipation on the Aguilar-Stiles model, in the visual matches. We develo p a method for computing visual jnds of predicted rod intrusion; i.e., an analytical expression for rod mismatch. With this, we compute poss ible rod mismatch for 922 metameric pairs of lights, each pair pronoun ced a visual match by one or another of eight normal observers, by usi ng the Trezona expression for pupil diameter or by arbitrarily assigni ng pupil diameters of 4, 6, 8, or 10 mm. We find some evidence of poss ible rod participation in the matches, under certain conditions, in sm all parts of the (brightness)-(fieldsize)-(spectral composition) three -space. On the Aguilar-Stiles model, rod participation is not an appre ciable contributor to the troublesome tristimulus errors documented, i n earlier parts of this series of articles, to be present at high and low field brightness and at large (10 degrees) and small (1.3 degrees) visual fields. (C) 1998 John Wiley & Sons, Inc.