In 1940 the Inter-Society Color Council began the development of its color aptitude test. At the request of professional and industrial groups, the ISCC established a subcommittee, problem 10, to develop a test that would measure an operator's capability to make valid and reliable judgemnts of the likeness and difference of color samples. Dimmick was the co-chairman of this committee and results about the findings of the subcommittee have appeared in various numbers of the newsletter.