Yellow is the color evoked by light that stimulates both the L and M (long and medium wavelength) cone cells of the retina about equally, with no significant stimulation of the S (short-wavelength) cone cells. Light with a wavelength of 570–590 nm is yellow, as is light with a suitable mixture of red and green. Yellow's traditional RYB complementary color is purple, violet, or indigo, while its colorimetrically defined complementary color in both RGB and CMYK color spaces is blue.