Abstract

While reading is generally optimal with a high luminance-contrast text, the role of color contrast in reading performance has not been quantitatively studied. We examined the influence of color contrast on the reading rate in normal observers for a range of character sizes spanning those of everyday reading. Text was presented on a CRT either in pages (several lines at once) or scrolled (drifting from right to left) on a white background of 48 cd/m². Four conditions were examined: (1) high contrast (achromatic); (2) low contrast (achromatic); (3) low contrast (achromatic + chromatic); and (4) near equiluminant (chromatic). Chromatic contrast affected low (~0.12) contrast reading only for the smallest character sizes. This effect, the direction of which depended on the color of the text, could not be accounted for by focus errors to the chromatic stimuli. Reading rates for near equiluminant text (<0.01 contrast) were about half of those for a high-contrast text with medium width characters and worse for smaller characters but were, nevertheless, much higher than those reported by other investigators for the text of comparable luminance contrast in the absence of chromatic contrast.

© 1988 Optical Society of America