Black - http://en.wikipedia.org/wiki/Black

Black is the color of objects that do not emit or reflect light in any part of the visible spectrum; they absorb all such frequencies of light. Although black is sometimes described as an "achromatic", or hueless, color, in practice it can be considered a color, as in expressions like "black cat" or "black paint".


Black can be defined as the visual impression experienced when no visible light reaches the eye. (This makes a contrast with whiteness, the impression of any combination of colors of light that equally stimulates all three types of color-sensitive visual receptors.)
Pigments that absorb light rather than reflect it back to the eye "look black". A black pigment can, however, result from a combination of several pigments that collectively absorb all colors. If appropriate proportions of three primary pigments are mixed, the result reflects so little light as to be called "black".

This provides two superficially opposite but actually complementary descriptions of black. Black is the lack of all colors of light, or an exhaustive combination of multiple colors of pigment. See also Primary colors

In physics, a black body is a perfect absorber of light, but by a rule derived by Einstein it is also, when heated, the best emitter. Thus, the best radiative cooling, out of sunlight, is by using black paint, though it is important that it be black (a nearly perfect absorber) in the infrared as well.
In elementary science, far Ultraviolet light is called "black light" because, unseen, it causes many minerals and other substances to fluoresce.
On January 16, 2008, researchers from Troy, New York’s Rensselaer Polytechnic Institute announced the creation of the darkest material on the planet. The material, which reflects only .045 percent of light, was created from carbon nanotubes stood on end. It absorbs nearly 30 times more light than the current standard for blackness, and is 3 times darker than the current record holder for darkest substance. Scientists claim that the new material has great potential in the manufacturing of solar panels.

A material is said to be black if most incoming light is absorbed equally in the material. Light (electromagnetic radiation in the visible spectrum) interacts with the atoms and molecules which causes the energy of the light to be converted in to other forms of energy, usually heat. This means that black surfaces can act as thermal collectors, absorbing light and generating heat(see Solar thermal collector).
Absorption of light is contrasted by transmission, reflection and diffusion, where the light is only redirected, causing objects to appear transparent, reflective or white respectively.