Yellow is the color evoke by light that stimulates both the L and M (long- and medium-wavelength) cone cells of the retina about equally, but does not significantly stimulate the S (short-wavelength) cone cells; that is, light with much red and green but not very much blue. Light with a wavelength of 570–580 nm is yellow, as is light with a suitable mixture of somewhat longer and shorter wavelengths. Yellow's traditional RYB complementary color is purple, violet or indigo. Yellow's colorimetrically defined complementary color in both RGB and CMYK color spaces is blue.