Visible spectrum

The visible spectrum (TV: State of Decay) broadly consisted of seven colours: red, orange, yellow, green, blue, indigo and violet. Rani Chandra remembered these colours as ordered with the mnemonic "Richard of York gave battle in vain." (TV: Sky)

Infrared light was outside the visible spectrum, (TV: State of Decay) with a longer wavelength than visible light. (TV: The Hungry Earth) On the other end, ultraviolet was light of a shorter wavelength than visible light, (AUDIO: Red Dawn) and was therefore invisible to the human eye, imperceptible to common forms of sight. (PROSE: Placebo Effect)

Some species, like the V'orrn, could see beyond this spectrum. Indeed, the V'orrn were able to see up to 380 alternate spectra of light, including both infrared and ultraviolet. (PROSE: Placebo Effect)