Unlike its close cousin red, magenta isn't a spectral color - you won't find it in a natural rainbow. Magenta earned its place in printing because it's the most efficient single pigment for absorbing green light while reflecting both red and blue. Magenta's unique properties make it irreplaceable - no other single pigment can achieve the same selective absorption pattern. Alternative red pigments either absorb too much blue light or not enough green light to serve as an effective primary color. In modern printing, magenta ink uses quinacridone or xanthene-based pigments that absorb green light while reflecting both red and blue wavelengths.
Originally named "fuchsine" after the fuchsia flower, this color got its modern name from the Battle of Magenta in 1859 - the same year a new aniline dye was created in this distinctive shade.