The report is intended to serve as a reference work for all those concerned with the selection, specifications, and use of signal * -light colors.It discusses the nature of the problem, and the mathematical representation, recognition, production, control, and use of such colors.The characteristics of different types of chromaticity boundaries and the purpose and effect of the requirement for similarity of chromaticity characteristics are given special consideration.The treatment is varied according to the intended use.The discussion of the control of colors and the section on the use of colors are nontechnical, whereas the section on the production of signal colors is designed for the colorimetrist who is faced with the problem of selecting limit filters or drafting a specification.(Author).