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".
Color or light in science
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 (per se), 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.
Absorption of light
In keeping with the law of conservation of energy
, as a black color surface absorbs the light
particles that hit it, the surface's particles are getting excited (excited particles = higher temperature
). The color black attracts heat and absorbs it making the object that is black warmer, because the particles have warmed up and are moving faster.
Usage, symbolism, colloquial expressions
Authority and seriousness
Black can be seen as the color of authority and seriousness.
- Black Watch is the senior Highland Regiment of the British Army.
- In Japanese culture, kuro (black) is a symbol of nobility, age, and experience, as opposed to shiro (white), which symbolizes serfdom, youth, and naiveté. Thus the black belt is a mark of achievement and seniority in many martial arts, whereas in, for example, Shotokan karate, a white belt is a rank-less belt which comes before all other belts. These ranks are called dan.
- In the long-running Japanese tokusatsu TV series Super Sentai (and its American counterpart, Power Rangers), black is one of the colors worn by the eponymous heroes.
- Black was the color of the Arab dynasty of Abbasid caliphs, which is the reason black is frequently used in flags of Arab countries.
- The riot control units of the Basque Autonomous Police in Spain are known as beltzak ("blacks") after their uniform.
- Traditionally, police vehicles ("panda cars") were in black and white.
- In arguments, things can be black-and-white, meaning that the issue at hand is dichotomized (having two clear, opposing sides with no middle ground).
- In ancient China, black was the symbol of North and Water, one of the main five colors.
- Black sky refers to the appearance of space as one emerges from the Earth's atmosphere.
- The term "black hole" is applied to collapsed stars. This term is metaphorical however, because few properties of black objects or black voids apply to black holes.
Ambiguity and secrecy
- A black box is any device whose internal workings are unknown or inexplicable. In theatre, the black box is a smaller, undecorated theater whose auditorium and stage relationship can be configured in various way.
- A black project is a secretive project, like Enigma Decryption, other classified military programs or operations, Narcotics, or police sting operations.
- Some organizations are called "black" when they keep a low profile, like Sociétés Anonymes and secret societies.
- A polished black mirror is used for scrying, and is thought to help see into the paranormal world without interference or distraction.
- Black frequently symbolizes ambiguity, secrecy, and the unknown.
Beliefs, religions and superstitions
- Black is a symbol of mourning and bereavement in Western societies, especially at funerals and memorial services. In some traditional societies, within for example Greece and Italy, widows wear black for the rest of their lives. In contrast, across much of Africa and parts of Asia, white is a color of mourning and is worn during funerals.
- In English heraldry, black means darkness, doubt, ignorance, and uncertainty.
- In the Maasai tribes of Kenya and Tanzania, the color black is associated with rain clouds, a symbol of life and prosperity.
- Native Americans associated black with the life-giving soil.
- The Hindu deity Krishna means "the black one".
- The medieval Christian sect known as the Cathars viewed black as a color of perfection.
- The Rastafari movement sees black as beautiful.
- Black Friday (shopping) occurs the day after Thanksgiving and is, statistically, the largest shopping day in the US. The idea is that the shopping that begins on this day can put a company into the black (i.e., make a profit) for the year.
- To say one's accounts are "in the black" is used to mean that one is free of debt.
- Being "in the red" is to be in debt—in traditional bookkeeping, negative amounts, such as costs, were printed in red ink, and positive amounts, like revenues, were printed in black ink, so that if the "bottom line" is printed in black, the firm is profiting.
- In Western fashion, black is considered stylish, sexy, elegant and powerful.
- The colloquialism "X is the new black" is a reference to the latest trend or fad that is considered a wardrobe basic for the duration of the trend, on the basis that black is always fashionable. The phrase has taken on a life of its own as a snowclone, and has been stretched and parodied as a rhetorical device and a cliche.
Symbolic dualism with white
- Black magic is a destructive or evil form of magic, often connected with death, as opposed to white magic. This was already apparent during Ancient Egypt when the Cush Tribe invaded Egyptian plantations along the Nile River.
- Evil witches are stereotypically dressed in black and good fairies in white.
- In computer security, a blackhat is an attacker with evil intentions, while a whitehat bears no such ill will. (This is derived from the Western movie convention.)
- In many Hollywood Westerns, bad cowboys wear black hats while the good ones wear white.
- Melodrama villains are dressed in black and heroines in white dresses.
- A "black day" (or week or month) usually refers to a sad or tragic time. The Romans marked fasti days with white stones and nefasti days with black.
- Black months include:
- The Black Death, also known as the Black Plague, was a pandemic in Europe which killed tens of millions of people.
- The Black Hole of Calcutta was the overcrowding of an impromptu prison cell in which many died.
- A black-hearted person is mean and unloving.
- A blacklist is a list of undesirable persons or entities (to be placed on the list is to be "blacklisted").
- Black comedy is a form of comedy dealing with morbid and serious topics.
- A black mark against you is a bad thing.
- A black mood is a bad one (cf Winston Churchill's clinical depression, which he called "my black dog").
- black market is used to denote the trade of illegal goods, or alternatively the illegal trade of otherwise legal items at considerably higher prices, e.g. to evade rationing.
- Black propaganda is the use of known falsehoods, partial truths, or masquerades in propaganda to confuse an opponent.
- Blackmail is the act of threatening to reveal information about a person unless the threatened party fulfills certain demands. This information is usually of an embarrassing or socially damaging nature. Ordinarily, such a threat is illegal.
- If you sink the black eight-ball in billiards before all others are out of play, you lose.
- The black sheep of the family is the ne'er-do-well.
- To blackball someone is to block their entry into a club or some such institution. In the traditional English gentlemen's club, current members vote on the admission of a candidate by secretly placing a white or black ball in a hat. If upon the completion of voting, there was even one black ball amongst the white, the candidate would be denied membership, and he would never know who had "blackballed" him.
Black pigments include carbon black
, ivory black