Abstract: Three experiments were conducted in which positive and negative contrast on visual display terminals were directly compared. Operator tasks included visual search and reading, with accuracy and timeliness of response measured. In all cases where significant differences exist, better performance was obtained with negative contrast (dark characters or symbols on a lighter background). The increases in performance range from a low of 2.0 percent to a high of 31.6 percent. Based on the above results, we believe that there are significant advantages in visual task performance obtained from the selection of negative contrast displays.

Current standards that require negative contrast appear to be justified, while future revisions of ANSI/HFS 100-1988 and other standards should seriously consider incorporating negative contrast as a recommendation or requirement.

Keywords: Background, dark vs. light; CRT; Complex systems; Contrast, negative; Design; Empirical studies; Polarity; Screen output; VDT/VDU; Visual search

Originally published: Proceedings of the Human Factors Society 34th Annual Meeting, 1990, pp. 1447-1451

Republished: G. Perlman, G. K. Green, & M. S. Wogalter (Eds.) Human Factors Perspectives on Human-Computer Interaction: Selections from Proceedings of Human Factors and Ergonomics Society Annual Meetings, 1983-1994, Santa Monica, CA: HFES, 1995, pp. 225-229.