Blue

From Wikipedia, the free encyclopedia.

For other uses, see Blue (disambiguation)

Blue is one of the three primary additive colors; blue light has the shortest wavelength range (about 420-490 nanometers) of the three additive primary colors. The English language commonly uses "blue" to refer to any color from blue to cyan.

An example of a blue color in the RGB color space has intensities [0, 0, 255] on a 0 to 255 scale. Blue is the complement of yellow. For this reason, blue 80A filters are used to correct for the excessive redness of tungsten lighting in color photography.

Many languages do not have separate terms for blue and green, and in the Swedish language, blå, the modern word for blue, was used to describe black until the early 20th century. The modern English word blue comes from the Middle English, where it began to be used along with bleu, an Old French word of Germanic origin (possibly Old High German blao, "shining"). A Scots and Scottish English word for "blue" is blae, from the Middle English bla ("dark blue", from the Old English blæd).

Sky

A clear sky on a sunny day appears blue because of Rayleigh scattering of the light from the Sun. Large amounts of water appear blue because red light around 750 nm is absorbed as an overtone of the O-H stretching vibration. Interestingly, heavy water is colorless, because the absorption band (~950 nm) is outside the visible spectrum.

Plants and animals

The common bluebell.

Blueberries.

• Blue agave (Agave tequilana var. weber) is a blue-leafed variety of the Mexican agave, used for making tequila.
• Blueback salmon (Oncorhynchus nerka) is a synonym for sockeye salmon.
• Bluebell may refer to both the bulbous plants in the Hyacinthoides genus of lilies, or the plants in the genus Mertensia.
• Blueberry refers to any of the plants in the genus Vaccinium, all of which have flowers with edible berries colored blue to blue-black, which are also called "blueberries."
• Bluebill is a synonym for scaup, the name for two diving ducks in the Aythya genus: Greater Scaup (Aythya marila) and Lesser Scaup (Aythya affinis).
• Bluebirds are any of the North American songbirds in the genus Sialia: Eastern Bluebird (Sialia sialis), Western Bluebird (Sialia mexicana), or Mountain Bluebird (Sialia currucoides). They are medium-sized thrushs that usually have blue plumage and, in males, a rust-color breast.
• Bluebonnets are two lupine annual flowers in the Lupinus genus that are native to Texas: Lupinus subcarnosus and Lupinus texensis. They have a light blue appearance and palmately compound leaves.
• Bluebottles or blow-flies are any of the flies in the genus Calliphiora that have a brightly-colored metallic body and breed in decaying organic material.
• Blue catfish (Ictalurus furcatus) is a long bluish North American catfish species, often weighing more than 45 kg (100 pounds).
• Blue poison dart frogs (Dendrobates azureus) are poisonous South American frogs that bioaccumulate neurotoxins in their blue skin.

A blue dog has a coat color that is primarily "bluish" gray or silver. Examples include the Kerry Blue Terrier with a solid "blue" coat and some Australian Shepherds and Border Collies, which have merle coats. (See also Blue Dog Democrats, below).

Symbolism and expressions

Picasso's Self-portrait with Cloak (1901)

Blue often denotes injury, such as in the phrase "black and blue," since it is the color of a bruise. Blue is used also as a word to denote a sad or melancholy state, as in depression, or simply a state of deep contemplation (however, the phrase "blue skies," referring to sunny weather, implies cheerfulness). Symbolically, blue is associated with that state, such as the term blue period to describe Pablo Picasso's work form 1901 to 1904.

• In Australia, a "blue" can also describe a fight or an argument. Men with red hair may be nicknamed "Bluey". The phrase "true blue" also means "genuine" (example : "He's a true blue Aussie").

A "blue joke" or "blue comedy" is comedy which uses references to socially taboo subjects such as sexual or lavatorial double entendre.

• Blue law is the term for laws regulating issues of morality, such as alcohol, gambling, or pornography.

• Because blue is traditionally the color of heaven, parents once wrapped their baby boys in blue to protect them from demons. Pink was later chosen as the color to associate with girls.

• Blue is the color of the snooker ball which has a 5-point value.

• Blue is a variety of credit card issued by American Express.
• The German word for blue is used for "drunk". "blau machen" (make blue) means to skip work.
• In Russian, the word for light blue is slang for "gay".
• Blue movie is a slang term for a pornographic film. There are also "blue magazines". This term is most common in Britain but also used in the United States and Israel.

Books and written works

A "blue book" is an almanac or similar reference work. For example, the Oregon Blue Book is the official directory and fact repository of the state of Oregon, while the Harvard Bluebook dictates a style of legal citation. The Blue Book is a term for a policy document issued by the Federal Communications Commission in the United States in 1946, urging television networks to uphold their commitment to public service. The Kelley Blue Book is a popular guide used for automobile prices.

Blue pages are a telephone directory of government offices—either an official blue book or a section of a commercial directory. Compare with the yellow pages or white pages.

In The Hitchhiker's Guide to the Galaxy there are several references to the Hooloovoo, "a super-intelligent shade of the color blue."

Prizes

"Blue ribbon" is a term used to describe something of high quality, such as a blue-ribbon panel or a blue-ribbon commission. This comes from the practice of awarding blue ribbons for first place in competitions. The Blue Riband is a prize awarded since the 1860s to the ship that made the fastest trans-Atlantic crossing.

Math, science, and technology

The "blue screen of death."

"Big Blue" is a nickname for IBM. The company's chess computer (which defeated chess champion Garry Kasparov) was called Deep Blue. Users of Microsoft Windows often use the term "blue" to describe a computer that has encountered a "blue screen of death."

A blue box is an electronic device with a tone pulsator that simulates a telephone operator's dialing console by replicating the tones used to switch long-distance calls and using them to route the user's own call, bypassing the normal switching mechanism. They were used to avoid charges for telephone calls.

A "blue chip" is the nickname for a stock that is thought to be safe and in excellent financial shape. In the United States, $1 bills are delivered by the Federal Reserve Bank in blue straps.

In medical diagrams, blue is used to represent veins carrying deoxygenated blood back to the heart. Deoxygenated blood is actually reddish violet. When a medical patient is not getting enough oxygen or has stopped breathing, however, their skin often takes a blue tint, a condition called cyanosis.

In astronomy, a blue moon is the second full moon in a calendar month, the third full moon in a season that has four, or a moon that appears blue because of particles in the atmosphere. All are uncommon enough that the expression "once in a blue moon" means "once in a great while" or "infrequently."

National, athletic, and university associations

This Israeli flag depicts a blue Star of David on a white background between two blue stripes. The color blue is mandated only as "sky blue," and the shade varies from flag to flag; sometimes it is a dark, almost navy blue, other times it is a very light blue.

Azzurro, a light blue, is the national color of Italy. Blue (along with white) is the national color of Israel and the color is seen on the Israeli flag.

Dark blue is associated with the University of Oxford and light blue with the University of Cambridge. The sporting colors of these universities are called "the blues."

A specific shade of dark blue is associated with Yale University. Blue Devils are the mascot of many American universities; Duke University's blue devils are the most famous but other universities with the mascot include Central Connecticut State University, Dillard University, Lawrence Technological University, State University of New York at Fredonia, and the University of Wisconsin-Stout.

The Columbus Blue Jackets are a National Hockey League team based in Columbus, Ohio. The Blue Jays are the mascots of the Toronto Blue Jays, a Major League Baseball team, and its two minor league affilates: the Dunedin Blue Jays in Dunedin, Florida, and the Pulaski Blue Jays in Pulaski, Virginia.

Social class and occupation

Blue may denote the working class, derived from the traditional color of factory uniforms. Blue-collar workers are industrial workers and are often contrasted white-collar office workers. However, in contrast to "blue collar," the phrase "blue blood" is used to mean "from an aristocratic background," because pale, untanned skin–a sign of notablity–allows blue-tinged veins to show through.

Several vocations are associated with blue. Law enforcement, and uniformed police, often wear blue uniforms and have become associated with the color, as seen in phrases such as "boys in blue," "blue line," and "blue wall." Most police cars have blue colors, and United Nations peacekeepers are uniformed in blue and white. "Bluecoat" (akin to "redcoat") refers to a uniformed police officer. Police in the People's Republic of China changed the color of their uniforms from green to blue in the late 1990s, partly to emphasize their civilian role. Since laws prohibit police from declaring a strike, the "blue flu" is a "sickout": a type of strike action in which police call in sick.

Blue is associated with many air forces and navies because of the color of their dress uniforms, while green is associated with armies. Navy blue is a particular shade of blue worn by sailors in the Royal Navy since 1748 and subsequently adopted by other navies around the world. The Blue Angels are an acrobatic flight squadron of the U.S. Navy.

Politics

Logo of the congressional Blue Dog Democrats.

Blue, like white, may represent authority as opposed to revolutionary red or black.

During the American Civil War, blue was used to represent the Union while gray represented the Confederacy. This representation was based on the uniforms worn by the respective armies, although uniforms remained non-standard thoughout the war and sometimes the colors were switched.

Internationally, blue is the symbol for conservatism and conservative political parties. There are several notable exceptions and different meanings.:

• In the United States, since the 2000 presidential election, blue represents the leftist Democratic Party, and "blue states" are states that tend to favor the Democrats. (The rival rightist Republicans became associated with red, and states that favor the Republicans are "red states." Prior to 2000, electoral maps either used blue to represent the incumbent and red for the challenger, or alternated. Each party uses all national color (red, white, and blue) in official materials. The Blue Dog Democrat coalition is a caucus of moderate Democrats in Congress.
• In Puerto Rico, blue is the color of the National Progressive Party, which favors statehood.
• In the United Kingdom and Canada, blue represents the Conservative Party and Conservative Party of Canada, respectively.
• In Germany, blue and yellow are the colors of the liberal Free Democratic Party.
• In Paraguay, blue is the color of the Authentic Radical Liberal Party.
• In the Republic of China (Taiwan), blue is the symbol for the Kuomintang and is associated with the Pan-Blue Coalition of parties that support Chinese reunification.

Television

Blue is the color and name of the main character in the preschool animated television show Blue's Clues.

On Star Trek, medical and scientific personnel wear blue uniforms.

Music

Blues is a music genre. A blue note is a note between the regular notes on the scale. Blue notes are the most important notes in the blues scale.

Bands called "Blue" include two British musical groups: the rock group Blue and the boy band Blue. Blue is the title of an album by the Canadian singer-songwriter Joni Mitchell, and Kind of Blue is the title of an album by Miles Davis, one of the world's best-selling jazz recordings.

Blue Train is an influential jazz album by John Coltrane. Rhapsody in Blue is a symphonic jazz composition for jazz band, piano, and orchestra by George Gershwin, while Love is Blue is a popular tune from the 1960s by Andy Williams, most notably performed by Paul Mauriat.

"Blue" has been used as a song title by many artists, notably LeAnn Rimes and Eiffel 65. Cristian Castro's song "Azul" (Spanish for "blue") repeats the line "This love is blue as the sea" (Este amor es azul como el mar).

Other songs which use the word blue include:

• "We the People Who Are Darker than Blue" by Curtis Mayfield, appearing on his debut album
• "Blue Room in Archway" and "Song from the Blueroom" by The Boo Radleys, both appearing on the album Kingsize
• "For You Blue" by The Beatles, appearing on the album Let It Be
• "Blue Savannah" by Erasure, appearing on the album Wild!
• "Dark Blue" by No Doubt, the last track on their album "Return of Saturn"

Use in painting

Traditionally, blue has been considered a primary color in painting, with the secondary color orange as its complement, but this is not consistent with modern scientific color theory. As the mixing of pigments is a subtractive color process, the true primary colors in painting and printing are cyan, magenta and yellow (with black often added for practical reasons; see CMYK color model).

Variations

• Azure
• Aquamarine
• Alice-Blue
• Turquoise
• Cornflower blue
• Sky blue
• Royal blue
• Midnight blue

Blue pigments

• Azurite
• Cerulean blue
• Cobalt blue
• Phthalocyanine blue
• Prussian blue
• Ultramarine

lapislazuli

See also

• Distinguishing "blue" from "green" in language
• List of colors
• Lapis lazuli

External links

Look up blue on Wiktionary, the free dictionary.

• Is water blue? The absorption spectrum of water in the visible range