- The rainbow colours (ROYGBV) in order of wavelength are red (longest wavelength), orange, yellow, green, blue and violet (shortest wavelength).
- It is the sensitivity of the human eye to this small part of the electromagnetic spectrum that results in our perception of colour.
- Naming rainbow colours is a matter more closely related to the relationship between perception and language than anything to do with physics or scientific accuracy.
- Even the commonplace colours associated with rainbows defy easy definition. They are concepts we generally agree on, but are not strictly defined by anything in the nature of light itself.
- Whilst the visible spectrum and spectral colour are both determined by wavelength and/or frequency it is our eyes and brains that interpret these differences in electromagnetic radiation that result in our colour perceptions.
- Modern portrayals of rainbows have reduced the number of colours to six – ROYGBV. One reason for this is because it is easier to portray using RGB colour.
- RGB colour is a technology principally used to reproduce colour using digital and electronic equipment. RGB colour is an additive colour model in which red, green and blue light is combined in various proportions to reproduce a wide range of other colours. The name of the model comes from the initials of the three additive primary colours, red, green, and blue.