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.
On a browser that supports visual formatting in Cascading Style Sheets, the following box should appear in this color:
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.
- 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, red is traditionally used for the following parties: