Colors and Legibility: Caution and Warning Data-Plates

The study compared the legibility of black printing on a yellow background with the legibility of five color combinations often used for caution and warning plates. The plates were tested under three light levels low red, low white, and high white. Results showed that black on yellow and white on black were significantly more legible than the other four color combinations in at least one of the light levels, as well as when data were pooled for all three light levels.