sentences:  MacAdam was a leading member of the committee of the Optical Society of America that in 1947, at the suggestion of the U.S. National Research Council, began work on a perceptually uniform colorimetric model of the color solid.Upon the retirement of its first chairman D. B. Judd, MacAdam was elected chair.The result of the committee's work was published in 1974 as ‘Uniform Color Scales,’ with OSA publishing a related color atlas with 558 samples in 1977.