Older operators need higher brightness levels to distinguish colors. Colors change in appearance as the ambient light level changes. The magnitude of a detectable change in color varies across the spectrum. It is difficult to focus upon edges created by color alone. Avoid red and green in the periphery of large displays.
Opponent colors go well together.
Physics of color, color vision, color models, color perception. Color Theory and Its Application in Art and Design , G. A. Agoston, Springer Verlag, 1987. Evolution in Color , Frans Gerritsen, Schiffer Publishing Ltd., 1988. Colorimetry , ed by Michael Bass, McGraw-Hill, New York, 1995. A Practical Guide for Color Mixing, Harald Kueppers, Barron's Educational Series, Inc., 1982.