Visible spectrum

The visible spectrum, (TV: State of Decay) broadly consisted of seven colours, forming the rainbow, each with "a million variations in between". (PROSE: The Squire's Crystal) These were 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)

White light was composed of every colour in the spectrum. (PROSE: The Squire's Crystal)

The broader spectrum stretched further, from infrared to ultraviolet. (PROSE: The Squire's Crystal) Infrared light, which was outside the visible spectrum, (TV: State of Decay) had 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) which 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)

Bernice Summerfield was able to perceive both infrared and ultraviolet whilst divorced from her body, which had been taken over by Avril Fenman. (PROSE: The Squire's Crystal)