The wavelengths of visible light present in the environment.
The wavelengths absorbed, transmitted, or reflected by an object or medium.
The perception of colour can be affected by factors such as brightness, contrast, and saturation, which are related to the amount of light present in a stimulus and its interaction with the eye and brain.
The observed colour of light is determined by its wavelength, not its frequency. However, as light travels from one medium to another, such as from air to glass, the colour seen by an observer may change due to refraction causing colours to disperse in different directions.