Polychromatic is the term used for light consisting of two or more wavelengths. Light from the sun or from artificial light sources (except for lasers) is polychromatic. The spectral distribution (spectrum) indicates the relative intensity of the different wavelengths present. The wavelength range is referred to in terms of bandwidth: wide band light appears whitish, narrow band light coloured. Polychromatic light can be compared with a sound containing many tones. Monochromaticity