The RGB color model is "additive" in the sense that the three light beams are added together, and their light spectra add, wavelength for wavelength, to make the final color's spectrum. This is essentially opposite to the subtractive color model, particularly the CMY color model, that applies to paints, inks, dyes, and other substances whose color depends on "reflecting" the light under which we see them. Because of properties, these three colors create white, this is in stark contrast to physical colors, such as dyes which create black when mixed.