The spectrum was a pattern of light. The electromagnetic spectrum consisted of visible light, ultraviolet light, infrared light, gamma rays, x-rays, and many other types of light. Different species were sensitive to different spectrums of light. Humans and Ithorians were just two examples of species whose eyes could see visible light. Umbarans and Defel were sensitive to ultraviolet light. Some species, such as Kaminoans could see in multiple spectrums, however, they could only see color in one: ultraviolet.