Page:Journal of the Optical Society of America, volume 30, number 12.pdf/25

 detail, but Figs. and are shown to illustrate the nature and extent of the work.

shows the working plot for RP 3/6. It includes the diffuse-normal, König-Martens spectrophotometric data, with some check points; the 45°-normal Martens photometer (with filters) data; the 45°-normal photographic data, 370 to 460 mμ, showing the absorption from the ZnO below 400 mμ; the plotting to a 10-times scale of values below 0.10; and the smooth curves drawn through the diffusenormal and the 45°-normal data. The final judgment as to the true course of all of the curves (representing the adopted values) was made by the senior author of the present paper.

IV. ''Trichromatic analysis of Munsell Atlas colors, 1926 data, 45° illumination. Values computed from spectrophotometric data given in Bureau of Standards Test Report 46,045 on the basis of the I.C.I. standard observer and coordinate system and for I.C.I. Illuminant C.''

''Average values of Y for samples in 1919 and 1926 tests. These values are computed from the data of Tables II, III and IV, except for the neutral samples, for which the values are taken from Bureau of Standards Technologic Paper No. 167.''

is one of the ten illustrations in the original report which show the deviations between the data as adopted for the diffuse-normal and the 45°-normal conditions. These blue-green samples have been selected for illustration because they show the greatest variation in dominant wave-length. also illustrates the general tendency for the apparent reflectances for the diffuse-normal conditions to be higher than those for the 45°-normal conditions.

Colorimetric computations were not made in 1919 nor in 1926, but have been completed during the past year, computations of the 1926