optimal color

optimal color (In French stimulus de couleur) optimaux surface color whose color impression is created from the mixture of 100% light spectral colors. An optimal color (W. Ostwald: “full color” is thus the lightest possible and most saturated color of this chromaticity, and there is only this one optimal color for this one chromaticity. On account of the 100% level of the spectral colors, the curve of its spectral luminance factor does not have a bell-like shape but a rectangular form, and knows only the two ideal values 0 (maximum absorption) and 1 (maximum remission). With respect to their positions in the visible spectral range, the optimal colors are subdivided into “midwave colors” (100% in the center of the spectrum, e.g. an optimal green) and “out of midwave colors” (0% in the center of the spectrum, e.g. an optimal magenta) as well as “longwave end colors”(100% at the long-wave end, e.g. an optimal red) and “shortwave end colors” (100% at the short-wave end, e.g. an optimal cyan). In practice, an approximation to optimal surface colors is attempted through the purity of the pigments, but almost all coloring substances have a gradual transient response between remission and absorption.