Abstract
Two experiments were designed to determine effective colors for stimulus lights as measured by speed of detection and accuracy of identification. Additionally, the nature of the interactions between stimulus color, background color, and amount of ambient illumination were assessed. Responses to four stimulus lights, viz., red, green, yellow, and white, were evaluated against four colored backgrounds, viz., copper, tan, blue, and green, under two levels of ambient illumination. Responses of 144 subjects were also evaluated according to sex.