Why doesn’t mixing colors give white?

Paints absorb some areas of the spectrum. The absorption spectrum of a mixture of two dyes will be the sum of the absorption spectra of each of them, so the absorption of the mixture at any wavelength can only be greater, but not less than the absorption of each dye separately. Thus, having selected several colors, it is possible to overlap the entire spectrum with absorption bands and obtain black, but white cannot be obtained in this way.