The standard color matching functions show that a trichromatic imaging system could not in principle render nearly a half of colors (especially among the saturated ones) seen by a normal observer even if the primaries used were monochromatic spectral colors of maximum saturation. The trichromatic systems cannot also accurately render the rest of colors since they are unable to simulate the non-existing linear transforms of the alternating matching functions of a triad of real primaries to a triad of non-negative spectral sensitivities of the three hypothetical cones. Even in its modernized, opponentcolor form, the trichromatic hypothesis cannot obviate numerous experimental inconsistencies and is forced to involve a kind of chromatic influence of the retinal rods. The recently proposed approach to consider the rod and the cone as two color receptors that intrareceptorally perform the blue-yellow and red-green opponent color separation, respectively, eliminates the controversy. It permits to determine and simulate (a) the four necessary chromatic imaging primaries corresponding to the four basic visual sensations and (b) the spectral sensitivities of the respective pairs of differential opponent receptors within the rod and cone, as well as (c) the spectral location of colors which evoke the primary sensations in their most intensive and saturated states. The approach appears to provide an actual separation of chromatic and achromatic (white) components of a color in the form of their orthogonal (non-correlated over the visible spectrum) matching factors.