Red

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For other uses, see Red (disambiguation).
Red
— Color coordinates —
Hex triplet #FF0000
RGBa (r, g, b) (255, 0, 0)
HSV (h, s, v) (0°, 100%, 100%)
a: Normalized to [0–255] (byte)

Red may be any of a number of similar colours at the lowest frequencies of light discernible by the human eye. Red is one of the three primary colours of visible light, the others being green and blue. Red light has a wavelength range of roughly 625–760 nm. Frequencies lower than this are called infrared, or below red and cannot be seen by human eyes, although some infrared frequencies can be felt as heat.

Red is an additive primary colour of light, complementary to cyan. It was once considered to be a subtractive primary color, and is still sometimes erroneously described as such in non-scientific literature; however, the colors cyan, magenta and yellow are now known to be closer to the true subtractive primary colors detected by the eye, and are used in modern color printing.

Red poppies.
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Red poppies.

One common use of red as an additive primary colour is in the RGB colour model. Because "red" is not by itself standardised, colour mixtures based on red are not exact specifications of colour either. In order to produce exact colors the colour red needs to be defined in terms of an absolute colour space such as sRGB. As used in computer monitors and television screens, red is very variable, but some systems may apply colour correction (so that a standardised "red" is produced that is not in fact full intensity of only the red colourant). In HSV colour space, red has a hue of 0° or 360°.

 

#FF0000

Contents

[edit] Red in culture

[edit] Symbolism

  • Red catches people's attention, and is often used to indicate danger or emergency.
    • Red symbolizes heat and fire. Taps for hot water are often labeled red. Red is commonly the color of fire alarm boxes, fire extinguishers, and the firefighter profession itself.
    • Red denotes "stop" in, for instance, stop signs, traffic signals, brake lights, or the flashing lights of a school bus.
    • Red is the color of blood, and a Red Cross, Red Crescent or Red Crystal emblem signifies medical personnel, facilities, or equipment, or the Geneva Conventions.
    • Red indicates extreme danger on Western color-coded scales, such as wildfire hazard signs or the U.S. Homeland Security Advisory System. It also denotes the maximum level of danger and preparedness as in the phrases condition red and red alert.
    • In auto racing, a red flag signals all cars to immediately stop.
    • The redline is the maximum speed an engine and its components can safely run.
    • Emergency exits on passenger aircraft are indicated by red signs and lighting.
    • "Redlining" is delineating a forbidden area (as on a map), for instance where a company denies or increases the cost of services, and is illegal in various circumstances in the U.S.
    • With ships on collision courses, the ship on starboard tack sees the Green for Go light on the ship on port tack, while the ship on port tack sees the Red for Stop light on the ship on starboard tack.
  • Rosso corsa is the traditional color of Italian race cars.
  • Being the color of blood, red was associated in Roman mythology with the god of war, Mars, and the reddish planet Mars became named after him. The phrase "red-blooded" describes someone who is audacious, robust, or virile; it is sometimes used to contrast with a cold or effete "blue blood" although the terms are unrelated in origin.
  • Red is the colour of the passion (emotion), romance and sex, (because of its association with blood, which is responsible for arousal) thus the red of a Valentine heart and of a "red-light district". It also represents the female menstrual cylce and therefore maturity and sexuality. Paradoxically, it also denotes anger, as in the expression seeing red, or embarrassment, as in being red-faced (many of these effects themselves caused by the blood rushing to the brain from adrenaline).
  • In the FIFA World Cup, red is the colour of victory in South Korea.
  • Red is considered holy in some parts of sub-sahara Africa. In these regions women are forbidden to wear red clothes.
  • Before the French revolution red was the colour of the flag signifying the imposition of martial law.
Chinese wedding gown
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Chinese wedding gown
Stop sign used in English-speaking countries, as well as in the European Union
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Stop sign used in English-speaking countries, as well as in the European Union
A red sunset in the Southern Hemisphere often signifies that the next day will be hot
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A red sunset in the Southern Hemisphere often signifies that the next day will be hot

[edit] Military and politics

  • In the United States wearing red clothing is promoted by some groups to symbolize support for or opposition against the Iraq War, or to spread awareness about heart disease. See: Red Friday
  • Red is also used to symbolize AIDS awareness or Drug awareness, in the form of a red ribbon

[edit] Science, technology and computing

  • Red is the color used for critical or important systems (such as emergency lighting) that operate in low-light or night-time conditions, as rod cells in the human eye do not respond to it and therefore does not interfere in the eye's ability to focus in dim environments.
  • A red filter used in black and white photography increases contrast in most scenes. For example, combined with a polarizer, it can turn the sky black. Films simulating the effects of infrared film (such as Ilford's SFX 200) do so by being much more sensitive to red than to other colors.
  • Oxygenated blood is red due to the presence of oxygenated hemoglobin.
  • Red light is the first to be absorbed by sea water, so that many fish and marine invertebrates that appear bright red are black in their native habitat.

[edit] Variations

  Shades of red  
Alizarin Burgundy Cardinal Carmine Cerise Chestnut Crimson Falu red Fuchsia Magenta Maroon Mauve
                       
Red Red-violet Rust Puce Sangria Scarlet Terra cotta Vermilion Amaranth Rose Hollywood Cerise Shocking Pink
                       
Coral Red
 
Sandstone interior of Antelope Canyon, displaying various reddish hues
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Sandstone interior of Antelope Canyon, displaying various reddish hues

[edit] In fiction

[edit] In other languages

Hungarian has two words for red, medium piros and dark vörös, which are distinct colours the way red and pink are distinct colours in English.

In Turkish there are numerous words for red: Al generally refers to the color of blood and related things (blushing, Turkish flag); Kızıl is bright red, and generally refers to fire or rebellion (sunset, communist). Kırmızı is a more general word for red, without strong emotional meaning.

In some decorating and fashion contexts, shades of red are described by reference to the colours of fruits and vegetables that commonly match that shade. These include cherries, beets, turnips, strawberries (often used in referring to "strawberry blonde" hair), and raspberries (as referenced in the Prince song "Raspberry Beret"). While the most popular colour for apples is a dark shade of red, the fruit is usually invoked in fashion or decorating to reference a pale yellowish green.

In Welsh a "blue" movie (i.e. pornographic) is called a ffilm goch (a red movie).

[edit] Red pigments

[edit] See also

Look up Red in
Wiktionary, the free dictionary.
Wikimedia Commons has media related to:


The Electromagnetic Spectrum
(Sorted by wavelength, short to long)
Gamma ray | X-ray | Ultraviolet | Visible spectrum | Infrared | Terahertz radiation | Microwave | Radio waves
Visible (optical) spectrum: Violet | Blue | Green | Yellow | Orange | Red
Microwave spectrum: W band | V band | K band: Ka band, Ku band | X band | C band | S band | L band
Radio spectrum: EHF | SHF | UHF | VHF | HF | MF | LF | VLF | ULF | SLF | ELF
Wavelength designations: Microwave | Shortwave | Mediumwave | Longwave


Template:Web colorus

[edit] External links