David MacAdam

[2] While still studying, MacAdam published in 1935 two papers on the theory of optimal object colors in which he showed the results of his calculations of the optimal object color solid raised over the CIE chromaticity diagram, using the newly established CIE standard observer and illuminant C and A data from 1932.

Assuming that the basis of color difference perception was the statistical error in matching the appearance of a given color stimulus he conducted an extensive experiment with one observer, the result of which was expressed in the CIE chromaticity diagram in form of statistically derived ellipses, published in 1942 (See Fig.

In attempting to convert the ellipses to circles of equal size MacAdam encountered the non-Euclidean nature of psychophysical color space.

[7] 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.

In addition to his contributions to Handbook of Colorimetry (1936) he was a major contributor to OSA's 1953 book The Science of Color.