Page:Journal of the Optical Society of America, volume 30, number 12.pdf/40



Some 400 color samples were obtained from the Munsell Color Company in November, 1934. These samples, backed by a standard white material, were compared spectrophotometrically against a freshly smoked surface of magnesium oxide deposited on magnesium carbonate. The spectrophotometer employed was of a type that records the diffuse reflection factors of the sample relative to those of the magnesium-oxide standard. These spectral reflection factors were converted by integration into tristimulus values, using a selected-ordinate method with thirty ordinates.

In Table I, column 1 indicates the Munsell designation of the color. Columns 2, 3, and 4 give the tristimulus values for the 1931 I.C.I. standard observer and Illuminant C. Columns 5 and 6 list the