Abstract

Traditionally, heterochromatic flicker photometry has been widely accepted as the method of choice for equating the relative luminance of two colors. Recently, a variety of additional methods have been used in studies of the spatial and temporal properties of chromatic mechanisms. Because of the importance of accurate luminance equation, we have compared results from flicker photometry, minimum apparent motion, and minimum contrast in the same subjects using the same equipment (a computer-generated raster graphics system). Field size (2°) and mean luminance (27.4 cd/m²) were held constant. The red and green guns of a Mitsubishi RGB monitor generated the colors to be compared. As we reported earlier,¹ significant method-dependent differences are found within a given subject. The direction and magnitude of such differences are idiosyncratic. Here we present data showing that some, although not all, of the subject and method dependent variations can be attributed to temporal factors. In particular, the difference between the red-green ratios determined by heterochromatic flicker and photometry and those determined by minimum contrast sensitivity measures may be substantially reduced for some subjects by equating temporal frequency for the two methods.

© 1988 Optical Society of America