Blue

Blue
Spectral coordinates
Frequency	~670–610 THz
Colour coordinates
Hex triplet	#0000FF
sRGBB (r, g, b)	(0, 0, 255)
HSV (h, s, v)	(240°, 100%, 100%)
Source	HTML/CSS
	B: Normalized to (byte);

Blue is one of the three primary colours of pigments in painting and traditional colour theory, as well as in the RGB colour model. It lies between violet and green on the spectrum of visible light. The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colors; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called Tyndall scattering explains blue eyes. Distant objects appear more blue because of another optical effect called atmospheric perspective.

Blue has been an important colour in art and decoration since ancient times. The semi-precious stone lapis lazuli was used in ancient Egypt for jewellery and ornament and later, in the Renaissance, to make the pigment ultramarine, the most expensive of all pigments. In the eighth century Chinese artists used cobalt blue to colour fine blue and white porcelain. In the Middle Ages, European artists used it in the windows of Cathedrals. Europeans wore clothing coloured with the vegetable dye woad until it was replaced by the finer indigo from America. In the 19th century, synthetic blue dyes and pigments gradually replaced mineral pigments and synthetic dyes. Dark blue became a common colour for military uniforms and later, in the late 20th century, for business suits. Because blue has commonly been associated with harmony, it was chosen as the colour of the flags of the United Nations and the European Union.

Surveys in the US and Europe show that blue is the colour most commonly associated with harmony, faithfulness, confidence, distance, infinity, the imagination, cold, and sometimes with sadness. In US and European public opinion polls it is the most popular colour, chosen by almost half of both men and women as their favourite colour. The same surveys also showed that blue was the colour most associated with the masculine, just ahead of black, and was also the colour most associated with intelligence, knowledge, calm and concentration.

Shades and variations

Blue is the colour of light between violet and green on the visible spectrum. Hues of blue include indigo and ultramarine, closer to violet; pure blue, without any mixture of other colours; Cyan, which is midway in the spectrum between blue and green, and the other blue-greens turquoise, teal, and aquamarine.

Blue also varies in shade or tint; darker shades of blue contain black or grey, while lighter tints contain white. Darker shades of blue include ultramarine, cobalt blue, navy blue, and Prussian blue; while lighter tints include sky blue, azure, and Egyptian blue. (For a more complete list see the List of colours).

Blue pigments were originally made from minerals such as lapis lazuli, cobalt and azurite, and blue dyes were made from plants; usually woad in Europe, and Indigofera tinctoria, or true indigo, in Asia and Africa. Today most blue pigments and dyes are made by a chemical process.

Pure blue, also known as high blue, is not mixed with any other colours
Navy blue, here worn by Admiral Horatio Nelson, is the darkest shade of pure blue
Sky blue or pale azure, mid-way on the RBG colour wheel between blue and cyan
Egyptian blue goblet from Mesopotamia, 1500–1300 BC. This was the first synthetic blue, first made in about 2500 BC.
Extract of natural indigo, the most popular blue dye before the invention of synthetic indigo
A block of lapis lazuli, originally used to make ultramarine
Ultramarine, slightly violet-blue, in a painting by Giovanni Bellini. It was the most expensive pigment of Renaissance.
Cobalt coloured the stained glass windows of Sainte-Chapelle in Paris (1250)
Prussian blue, the colour of the uniforms of the army of Prussia, was invented in about 1706
Vincent Van Gogh used the synthetic pigment cobalt blue for the sky of his starry night

Etymology and linguistic differences

The modern English word blue comes from Middle English bleu or blewe, from the Old French bleu, a word of Germanic origin, related to the Old High German word blao. In heraldry, the word azure is used for blue.

In Russian and some other languages, there is no single word for blue, but rather different words for light blue (???????, goluboy) and dark blue (?????, siniy). See Colour term.

Several languages, including Japanese, Thai, Korean, and Lakota Sioux, use the same word to describe blue and green. For example, in Vietnamese the colour of both tree leaves and the sky is xanh. In Japanese, the word for blue (? a

Release Date :

12:00am on Friday 16th October 2009