Page:Journal of the Optical Society of America, volume 30, number 12.pdf/28

 this relation all of the 1919 and 1926 data for the chromatic samples have been plotted on the (x, y)-diagram shown in. To assist in an evaluation of any consistent or erratic differences among the data two straight lines are plotted for each Munsell hue designation: First, a dashed line passing from the 5/5 point for each of the five principal hues through the point representing I.C.I. Illuminant C and on to the complementary; and second, a continuous line passing from the same 5/5 point through the point (DM) which results from disk mixture of these five principal hues in equal proportions.

To assist the reader to correlate the plotted points representing the experimental data with the proper pair of these dominant wave-length lines, each pair of points (45° and diffuse illumination) is connected by a light continuous line to the respective line of dominant wave-length, using the lines through DM for this purpose. The points chosen for the contact of the line