A study to determine how far from the fovea color differences can be detected and what the boundaries are for perception of individual hues. Just-noticeable color differences in peripheral vision may be divided into three types: discrimination by red and green components, by yellow and blue components, and achromatic discrimination. Results indicate a deuteranopic tendency in peripheral color vision. Color discrimination in the periphery improves in the regions of unique red and green where transitions in the perception of blue and yellow occur. -- AATA