colour Sensation experienced when light of sufficient brightness and of a particular wavelength strikes the retina of the eye. The colour of an object is normally the colour it reflects. For example, a blue car absorbs all colours except blue which is reflected. Normal daylight (white light) is made up of a spectrum of colours, each a different wavelength. These colours can be placed in seven bands – red, orange, yellow, green, blue, indigo and violet – of decreasing wavelength. A pure spectral colour is called a hue. If the colour is not pure but contains some white, it is ‘desaturated’ (tint). Saturation is the degree to which a colour departs from white and approaches a pure hue. A colour may also have luminosity (brightness) which determines its shade. Any colour is perceived as a mixture of three primary colours: red, green, and blue in light; or red, yellow, and blue in paint. A colour created by combining two primary colours is called a secondary colour.

colour (tone-colour). It is impossible for mus. to convey colours, but it is customary to speak of ‘colouring’ or ‘tone-colour’ where variations of timbre or tone are prod. by different intensities of the overtones of sounds. ‘Shade’ is perhaps a more accurate term, since the differences are often those of ‘darker’ or ‘lighter’ sound. But in his tone-poem Prometheus: The Poem of Fire, Op.60, Scriabin introduced a colour kbd. to project colours on to a screen, intended to convey the mood of the mus. The colour-organ was used for this purpose.

colour, U.S. color XIII. — OF. col(o)ur (mod. couleur) :- L. color, colōr-, rel. to cēlare hide, CONCEAL; see -OUR 2.
So colour vb. XIII. — OF. coulourer (mod. colorer) — L. colōrāre.

colour See PIXEL COLOUR.