Visible spectrum

The visible spectrum (TV: State of Decay) consisted of seven colours: red, orange, yellow, green, blue, indigo and violet. Rani Chandra remembered these colours as ordered in the saying "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)