Tests composed of pseudoisochromatic plates provide one of the simplest methods of distinguishing between normal and deficient red-green color perception. During World War II the only such test generally available in the United States was the series of 46 plates printed by Beck & Co. and distributed by the American Optical Company. In several investigations reviewed by Farnsworth and Kimble,1 it was shown that this series included many poor plates, some of which were failed almost as frequently by normal as by color-deficient subjects. To obtain a shorter and a more efficient dichotomous test, various selections of the more highly diagnostic plates were proposed. One of the earliest, a selection of 17 plates, known as the Abridged AOC Test,2 has been used since about 1944 by the Army Air Forces. A selection of 18 plates was proposed by Hardy, Rand, and Rittler,3 in 1947, spon- sored by