White

White is a color (more accurately it contains all the colors of the visible spectrum and is sometimes described as an achromatic color—black is the absence of color) that has high brightness but zero hue. The impression of white light can be created by mixing (via a process called "additive mixing") appropriate intensities of the primary color spectrum: red, green and blue, but it must be noted that the illumination provided by this technique has significant differences from that produced by incandescence (see below).

Color

Paint

In painting, white can be created by reflecting ambient light from a white pigment. White when mixed with black produces gray. To art students, the use of white can present particular problems, and there is at least one training course specialising in the use of white in art.

Related Topics:
Painting - Pigment - Gray

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There are various white pigments. Lead white, also known as flake white, is the traditional white pigment, but it is not much used now as it is toxic. Non-toxic alternatives are zinc white and titanium white. They are made from zinc oxide and titanium dioxide respectively.

Related Topics:
Lead white - Zinc oxide - Titanium dioxide

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White light

Until Newton's work became accepted, most scientists believed that white was the fundamental color of light; and that other colors were formed only by adding something to light. Newton demonstrated that white was formed by combining the other colors.

Related Topics:
Newton - Scientists

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In the science of lighting, there is a continuum of colors of light that can be called "white". One set of colors that deserve this description are the colors emitted, via the process called incandescence, by a black body at various relatively-high temperatures. For example, the color of a black body at a temperature of 2848 kelvins 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 color temperature of about 3200 K. Daylight has a nominal color temperature of 5400 K (called equal energy white), but can vary from a cool red up to a bluish 25,000 K. Not all black body radiation can be considered white light: the background radiation of the universe, to name an extreme example, is only a few kelvins and is quite invisible.

Related Topics:
Incandescence - Black body - Kelvins - Light bulb - Color temperature - Theatre - Radiation - Universe

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Standard whites

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 color temperature of 6,500 K, is taken to represent standard daylight.

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Computers

Computer displays often have a color temperature control, allowing the user to select the color temperature (usually from a small set of fixed values) of the light emitted when the computer produces the electrical signal corresponding to "white". The RGB coordinates of white are 255 255 255.

Related Topics:
Computer display - RGB

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