Red

Red is a color at the lowest frequencies of light discernible by the human eye. Red light has a wavelength of roughly 700 nm. Oxygenated blood is red due to the presence of hemoglobin.

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Lower frequencies are called infrared, or far red.

Usage, symbolism, colloquial expressions

• Red catches people's attention, and is often seen as a sign of danger: it is thus used for warning signs.
  • The color red is often used to denote anger as in seeing red.
  • The color of blood led red to be associated with the god of war, Mars, and the reddish planet Mars became named for him.
  • Red is used to denote "stop" in traffic signs and traffic signals.

• For a long time (beginning probably with the French Revolution) red was used as a colour of Revolutionaries, Leftist and generally radical groups, while white was used as colour of conservatives.
  • For instance the Civil War in Russia and the Civil War in Finland were fought between "Reds" and "Whites".
  • The identification of Communism as red (with red being the primary color of the flag of the Soviet Union) led to such Cold War phrases as "the Red Menace" and "Red China" (distinguished from Nationalist China or Taiwan).
  • In maps of political parties in the United Kingdom, red is normally used for the Labour Party

• In Chinese symbolism, red is the color of good luck and is used for decoration and wedding attire. Money in Chinese societies is traditionally given in red packets.

• Red is also used to denote debt - as well as losses on a balance sheet.

• In North American stock markets, red is used to denote a drop in stock prices. In East Asian stock markets, red is used to denote a rise in stock prices.

• In maps of political parties in the United States, red is traditionally used for the Republican Party, and in Canada, for the Liberal Party of Canada.