11. Also, the Abney effect does not disallow any and all straight lines on chromaticity diagrams . 12. Two-dimensional depictions include chromaticity diagrams : sections of the color solid with a fixed lightness. 13. On an xy chromaticity diagram the spectral locus if formed by all positive values of x and y. 14. The color hexagon : a chromaticity diagram based on photoreceptor excitations as a generalized representation of colour opponency. 15. If one adds white light to a monochromatic light, one will obtain a straight line on the chromaticity diagram . 16. On an rg chromaticity diagram the first quadrant where all values of r and g are positive forms a right triangle. 17. Note that the chromaticity diagram is a tool to specify how the human eye will experience light with a given spectrum. 18. Perley G . Nutting Jr . ( observer " PGN " ), plotted on the CIE 1931 xy chromaticity diagram . 19. The third depicted the locus of the isothermal chromaticities on the CIE 1931 " x, y " chromaticity diagram . 20. In color theory, a purple is a color along the line of purples on the CIE chromaticity diagram and excludes violet.
