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White is a color (although some describe it as an achromatic colour, or an absence of colour) that has high brightness but zero hue. White light can be created by mixing (in a process called additive mixing) appropriate intensities of the primary colours red, green and blue. It can also be created by reflecting ambient light from a white pigment such as paint.

White when mixed with black in different portions becomes the shades of grey (also, at least in the United States, commonly spelled "gray").

In the science of lighting, there is a continuum of colours of light that can be called "white". One set of colours that deserve this description are the colours emitted by a black body at various temperatures. For example, the colour of a black body at a temperature of 2848 kelvin matches that produced by domestic incandescent light bulbs. It is said that "the color temperature of such a light bulb is 2848 K". The white light used in theatre illumination has a colour temperature of about 3200 K. Daylight has a nominal colour temperature of 5400 K (called equal energy white), but can vary from a cool red up to a bluish 25,000 K.

Standard whites are often defined with reference to the International Commission on Illumination's (CIE's) chromaticity diagram. These are the D series of standard illuminants. Illuminant D65, originally corresponding to a colour temperature of 6,500 K, is taken to represent standard daylight.

Computer displays often have a colour temperature control, allowing the user to select the colour temperature (usually from a small set of fixed values) of the light emitted when the computer produces the electrical signal corresponding to "white".

Usage, symbolism, colloquial expressions

  • White noise, in acoustics, is a sibilant sound that is often a nuisance, although it can also be deliberately created for test purposes.

  • Whitewash[?], figuratively, means an attempt to obscure the truth by issuing a blanket of lies. See propaganda.

  • Whiteout[?] is a weather condition in which visibility is reduced to zero by snow.

  • White is colour of mourning in Chinese tradition.

  • A white flag is a parliamentary flag, to signify that an approaching negotiator is unarmed, but can also signify surrender.

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