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Blue
Blue is one of the three primary additive colours; blue light has the
shortest wavelength range (about 420-490 nanometres) of the three primary
colours. The English language commonly uses "blue" to refer
to any colour from blue to cyan.
A clear sky on a sunny day is coloured blue, because of Rayleigh scattering
of the light from the Sun. Large amounts of water (H2O) appear blue because
red light around 750 nm is absorbed as an overtone of the O-H stretching
vibration. Interestingly, heavy water (D2O) is colourless, because the
absorption band (~950 nm) is outside the visible spectrum.
An example of a blue colour in the RGB colour 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 colour photography.
Many languages do not have separate terms for blue and green, and in
the Swedish language, the word blue was used to describe for 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.
Plants and animals
1.Blue agave (Agave tequilana var. weber) is a blue-leafed variety of
the Mexican agave that is used for making tequila.
2.Blueback salmon (Oncorhynchus nerka) is a synonym for sockeye salmon.
3.Bluebell may refer to both the bulbous plants in the Hyacinthoides genus
of lilies, or the plants in the genus Mertensia.
4.Blueberry refers to any of the plants in the genus Vaccinium, all of
which have flowers with edible berries coloured blue to blue-black, which
are also called "blueberries".
5.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).
6.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). 7.They are medium-sized thrushs
that usually have blue plumage and, in males, a rust-colour breast.
8.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.
9.Bluebottles or blow-flies are any of the flies in the genus Calliphiora
that have a brightly-coloured metallic body and breed in decaying organic
material.
Law enforcement
Blue is associated with law enforcement, especially uniformed police.
This is seen in phrases such as "boys in blue", "blue line",
and "blue wall". Most police cars have blue colours, 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 colour 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.
Use, symbolism and colloquial expressions
1. Blue often denotes injury, such as in the phrase "black and blue",
since it is the colour of a bruise.
2. A "blue joke" or "blue comedy" is comedy which
uses references to socially taboo subjects such as sexual or lavatorial
double entendre.
3. "Blue laws" is a slang term for laws regulating issues of
morality, such as alcohol, gambling, or sexually-explicit materials.
4 .A "blue book" is an almanac or similar reference work. For
instance, the Oregon Blue Book is the official directory and fact repository
of the state of Oregon. The Harvard Bluebook dictates a style of legal
citation. The Kelley Blue Book is a popular guide to used car prices.
The Blue Book refers to 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.
5. Blue pages are a telephone directory of government offices, either
an official "blue book" or a section of a commercial directory,
contrasted with the yellow pages or white pages.
6. The Blue Riband is a prize awarded since the 1860s to the ship that
made the fastest transatlantic crossing.
7. "Blue ribbon" is a term used to describe something of high
quality, such as a blue ribbon panel or a blue ribbon commission. This
usage comes from the practice of awarding blue ribbons for first place
in certain athletic or other competitive endeavours.
8. Dark blue is associated with the University of Oxford and light blue
with the University of Cambridge. The sporting colours of these universities
are called blues.
9. "Big Blue" is a nickname for IBM. Deep Blue was its chess-playing
computer which defeated Garry Kasparov.
10. Users of Microsoft Windows often use the term "blue" to
describe a computer that has encountered a "blue screen of death".
11. Blue is generally associated with boys, and pink is associated with
girls.
12. 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.
13. 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 "once
in a blue moon" means "almost never".
14. A blue dog has a coat colour that is primarily grey or silver. For
example, see Kerry Blue Terrier for a solid "blue" coat or Australian
Shepherd for blue merle.
15. In The Hitchhiker's Guide to the Galaxy there are several references
to the Hooloovoo, "a super-intelligent shade of the colour blue".
16. On Star Trek, medical and scientific personnel wear blue uniforms.
17. Blue is the colour of the snooker ball which has a 5-point value.
18. Blue is the colour and name of the main character in the preschool
animated television show Blue's Clues.
Nationally
1. The colloquial expression "blue" is used to describe melancholy
or sadness in English speaking countries. See also Blues music. But "blue
skies", referring to sunny weather, implies cheerfulness.
2. 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").
3. The German word for blue is used for "drunk". "blau
machen" (make blue) means to skip work.
4. In Russian, the word for light blue is slang for "gay".
5. 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.
6. Azzurro (a light blue) is the national colour of Italy.
7. Blue (along with white) is the national colour of the State of Israel).
Vocations
Blue is associated with many air forces and navies from the colour of
their dress uniforms, navy blue for the latter. The Blue Angels are an
acrobatic flight squadron of the U.S. Navy.
Blue may denote the working class, derived from the traditional colour
of factory or shop uniforms. Blue-collar workers are industrial workers
as opposed to white-collar office workers.
In contrast to "blue collar", the phrase "of blue blood"
is used to mean "from an aristocratic background", because a
pale, untanned skin allows blue-tinged veins to show through.
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