# Blue

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Colour between violet and cyan on the visible spectrum of light

This article is about the colour. For other uses, see [Blue (disambiguation)](/source/Blue_(disambiguation)).

Blue Clockwise, from top left: A Ukrainian Police officer on duty; Tiles of the Sheikh Lotfollah Mosque, Iran; Red-legged honeycreeper; Copper(II) sulphate; The flag of the United Nations; Tahana Maru, French Polynesia; The Atlantic Ocean seen from space Spectral coordinates Wavelength approx. 450–495 nm Frequency ~670–610 THz Colour coordinates Hex triplet #0000FF sRGBB (r, g, b) (0, 0, 255) HSV (h, s, v) (240°, 100%, 100%) CIELChuv (L, C, h) (32, 131, 266°) Source HTML/CSS[1] B: Normalized to [0–255] (byte) H: Normalized to [0–100] (hundred)

**Blue** is one of the three [primary colours](/source/Primary_color) in the [RGB (additive) colour model](/source/RGB_color_model), as well as in the [RYB colour model](/source/RYB_color_model) (traditional colour theory).[2] It lies between [violet](/source/Violet_(color)) and [cyan](/source/Cyan) on the [spectrum](/source/Optical_spectrum) of [visible light](/source/Visible_light). The term *blue* generally describes colours perceived by humans observing light with a [dominant wavelength](/source/Dominant_wavelength) between approximately 450 and 495 [nanometres](/source/Nanometre). The clear daytime sky and the deep sea appear blue because of an optical effect known as [Rayleigh scattering](/source/Rayleigh_scattering#Cause_of_the_blue_color_of_the_sky). An optical effect called the [Tyndall effect](/source/Tyndall_effect) explains [blue eyes](/source/Eye_color#Blue). Distant objects appear more blue because of another optical effect called [aerial perspective](/source/Aerial_perspective).

Blue has been an important colour in art and decoration since ancient times. The semi-precious stone [lapis lazuli](/source/Lapis_lazuli) was used in ancient [Egypt](/source/Egypt) for jewellery and ornament and later, in the [Renaissance](/source/Renaissance), to make the pigment [ultramarine](/source/Ultramarine), the most expensive of all pigments.[3] In the eighth century Chinese artists used [cobalt blue](/source/Cobalt_blue) to colour fine [blue and white porcelain](/source/Blue_and_white_porcelain). In the [Middle Ages](/source/Middle_Ages), European artists used it in the windows of [cathedrals](/source/Cathedral). Europeans wore clothing coloured with the vegetable dye [woad](/source/Woad) until it was replaced by the finer [indigo](/source/Indigo_dye) from America. In the 19th century, synthetic blue dyes and pigments gradually replaced organic dyes and mineral pigments. 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](/source/United_Nations) and the [European Union](/source/European_Union).[4]

In the United States and across Europe, blue is the colour that both men and women are most likely to choose as their favourite, with at least one recent survey showing the same across several other countries, including China, Malaysia, and Indonesia.[5][6] Past surveys in the US and Europe have found that blue is the colour most commonly associated with [harmony](/source/Harmony), [confidence](/source/Confidence), [masculinity](/source/Masculinity), [knowledge](/source/Knowledge), [intelligence](/source/Intelligence), [calmness](/source/Calmness), [distance](/source/Distance), [infinity](/source/Infinity), the [imagination](/source/Imagination), [cold](/source/Cold), and [sadness](/source/Sadness).[7]

## Etymology and linguistics

The [modern English](/source/Modern_English) word *blue* comes from [Middle English](/source/Middle_English) *bleu* or *blewe*, from the [Old French](/source/Old_French) *bleu*, a word of [Germanic](/source/Germanic_languages) origin, related to the [Old High German](/source/Old_High_German) word *blao* (meaning 'shimmering, lustrous').[8] In [heraldry](/source/Heraldry), the word *[azure](/source/Azure_(heraldry))* is used for *blue*.[9]

In [Russian](/source/Russian_language), [Mongolian](/source/Mongolian_language), [Irish](/source/Irish_language), and some other languages, there is no single word for blue, but rather different words for light blue (Russian: голубой, *goluboy*) and dark blue (Russian: синий, *siniy*) (see [Colour term](/source/Colour_term)).

Several languages, including [Japanese](/source/Japanese_language) and [Lakota Sioux](/source/Lakota_language), use the same word to describe blue and green. For example, in [Vietnamese](/source/Vietnamese_language), the colour of both tree leaves and the sky is *xanh*. In Japanese, the word for blue ([青](https://en.wiktionary.org/wiki/%E9%9D%92#Japanese), *ao*) is often used for colours that English speakers would refer to as green, such as the colour of a [traffic signal](/source/Traffic_signal) meaning "go". In Lakota, the word *[tȟó](https://en.wiktionary.org/wiki/t%C8%9F%C3%B3)* is used for both blue and green, the two colours not being distinguished in older Lakota (for more on this subject, see [Blue–green distinction in language](/source/Blue%E2%80%93green_distinction_in_language)).

Linguistic research indicates that languages do not begin by having a word for the colour blue.[10] Colour names often developed individually in natural languages, typically beginning with [black](/source/Black) and [white](/source/White) (or dark and light), and then adding [red](/source/Red), and only much later – usually as the last main category of colour accepted in a language – adding the colour blue, probably when blue pigments could be manufactured reliably in the culture using that language.[10]

## Optics and colour theory

The term *blue* generally describes colours perceived by humans observing light with a [dominant wavelength](/source/Dominant_wavelength) between approximately 450 and 495 [nanometres](/source/Nanometre).[11] Blues with a higher frequency and thus a shorter wavelength gradually look more violet, while those with a lower frequency and a longer wavelength gradually appear more cyan. Purer blues are in the middle of this range, e.g., around 470 nanometres.

[Isaac Newton](/source/Isaac_Newton) included blue as one of the seven colours in his first description of the [visible spectrum](/source/Visible_spectrum).[12] He chose seven colours because that was the number of notes in the musical scale, which he believed was related to the optical spectrum. He included [indigo](/source/Indigo), the hue between blue and violet, as one of the separate colours, though today it would be categorised as blue.[13]

In traditional [colour theory](/source/Colour_theory), blue is one of the three [primary colours](/source/Primary_color) (red, yellow, blue), which can be mixed to form a decent [gamut](/source/Gamut) of colours (although the modern [CMY](/source/CMY_color_model) model is able to achieve a much wider gamut). Red and yellow mixed together form orange, yellow together and blue form green, blue and red form purple, and mixing all three primary colours together produces a dark brown. From the Renaissance onward, painters used this system to create their colours (see [RYB colour model](/source/RYB_colour_model)).

The RYB model was used for [colour printing](/source/Colour_printing) by [Jacob Christoph Le Blon](/source/Jacob_Christoph_Le_Blon) as early as 1725. Later, printers discovered that more accurate colours could be created by using combinations of cyan, magenta, yellow, and black ink, put onto separate inked plates and then overlaid one at a time onto paper. This method could produce almost all the colours with reasonable accuracy.

		- Additive colour mixing. The combination of [primary colours](/source/Primary_colour) produces secondary colours where two overlap; the combination red, green, and blue each in full intensity makes white.

		- Red, green, and blue [subpixels](/source/Subpixels) on a [liquid-crystal display](/source/Liquid-crystal_display).

On the [HSV colour wheel](/source/HSL_and_HSV), the [complement](/source/Complementary_color) of blue is [yellow](/source/Yellow); that is, a colour corresponding to an equal mixture of [red](/source/Red) and [green](/source/Green) light. On a colour wheel based on traditional colour theory ([RYB](/source/RYB_colour_model)) where blue was considered a primary colour, its complementary colour is considered to be [orange](/source/Orange_(colour)).[14]

### LED

Main article: [Blue LED](/source/Blue_LED)

In 1993, high-brightness blue LEDs were demonstrated by [Shuji Nakamura](/source/Shuji_Nakamura) of [Nichia Corporation](/source/Nichia_Corporation).[15][16][17] In parallel, [Isamu Akasaki](/source/Isamu_Akasaki) and [Hiroshi Amano](/source/Hiroshi_Amano) of [Nagoya University](/source/Nagoya_University) were working on a new development which revolutionised LED lighting.[18][19]

Nakamura was awarded the 2006 [Millennium Technology Prize](/source/Millennium_Technology_Prize) for his invention.[20] Nakamura, Amano and Akasaki were awarded the [Nobel Prize in Physics](/source/Nobel_Prize_in_Physics) in 2014 for the invention of an efficient blue LED.[21]

### Lasers

Main article: [Blue laser](/source/Blue_laser)

[Lasers](/source/Laser) emitting in the blue region of the spectrum became widely available to the public in 2010 with the release of inexpensive high-powered 445–447 nm [laser diode](/source/Laser_diode) technology.[22] Previously the blue wavelengths were accessible only through [DPSS](/source/DPSS) which are comparatively expensive and inefficient, but still widely used by scientists for applications including [optogenetics](/source/Optogenetics), [Raman spectroscopy](/source/Raman_spectroscopy), and [particle image velocimetry](/source/Particle_image_velocimetry), due to their superior beam quality.[23] Blue [gas lasers](/source/Gas_laser) are also still commonly used for [holography](/source/Holography), [DNA sequencing](/source/DNA_sequencing), [optical pumping](/source/Optical_pumping), among other scientific and medical applications.

## Shades and variations

Main article: [Shades of blue](/source/Shades_of_blue)

Various [shades of blue](/source/Shades_of_blue) labeled with HSL, RGB, and web color names.

Blue is the colour of light between [violet](/source/Violet_(color)) and [cyan](/source/Cyan) on the [visible spectrum](/source/Visible_spectrum). Hues of blue include indigo and [ultramarine](/source/Ultramarine), closer to violet; pure blue, without any mixture of other colours; Azure, which is a lighter shade of blue, similar to the colour of the sky; Cyan, which is midway in the spectrum between blue and [green](/source/Green), and the other blue-greens such as [turquoise](/source/Turquoise_(color)), [teal](/source/Teal), and [aquamarine](/source/Aquamarine_(color)).

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](/source/Cobalt_blue), [navy blue](/source/Navy_blue), and [Prussian blue](/source/Prussian_blue); while lighter tints include [sky blue](/source/Sky_blue), [azure](/source/Azure_(color)), and [Egyptian blue](/source/Egyptian_blue) (for a more complete list see the [List of colours](/source/List_of_colors)).

### As a structural colour

Further information: [Structural colouration](/source/Structural_colouration)

In nature, many blue phenomena arise from [structural colouration](/source/Structural_colouration), the result of interference between reflections from two or more surfaces of [thin films](/source/Thin_films), combined with refraction as light enters and exits such films. The geometry then determines that at certain angles, the light reflected from both surfaces interferes constructively, while at other angles, the light interferes destructively. Diverse colours therefore appear despite the absence of colourants.[24]

## Colourants

Main article: [Colourants](/source/Colourants)

		- [Egyptian blue](/source/Egyptian_blue)

		- [Cobalt blue](/source/Cobalt_blue)

		- [Copper phthalocyanine](/source/Copper_phthalocyanine)

		- [YInMn blue](/source/YInMn_blue)

		- [Prussian blue](/source/Prussian_blue), FeIII 4[FeII ([CN](/source/Cyanide)) 6] 3, is the blue of [blueprints](/source/Blueprint).

### Artificial blues

[Egyptian blue](/source/Egyptian_blue), the first artificial pigment, was produced in the third millennium BC in Ancient Egypt. It is produced by heating pulverised sand, copper, and [natron](/source/Natron). It was used in tomb paintings and funereal objects to protect the dead in their afterlife. Prior to the 1700s, blue colourants for artwork were mainly based on lapis lazuli and the related mineral ultramarine. A breakthrough occurred in 1709 when German druggist and pigment maker [Johann Jacob Diesbach](/source/Johann_Jacob_Diesbach) discovered [Prussian blue](/source/Prussian_blue). The new blue arose from experiments involving heating dried blood with iron sulphides and was initially called Berliner Blau. By 1710 it was being used by the French painter [Antoine Watteau](/source/Antoine_Watteau), and later his successor [Nicolas Lancret](/source/Nicolas_Lancret). It became immensely popular for the manufacture of wallpaper, and in the 19th century was widely used by French impressionist painters.[25] Beginning in the 1820s, Prussian blue was imported into Japan through the port of [Nagasaki](/source/Nagasaki). It was called *bero-ai*, or Berlin blue, and it became popular because it did not fade like traditional Japanese blue pigment, *ai-gami*, made from the [dayflower](/source/Dayflower). Prussian blue was used by both [Hokusai](/source/Hokusai), in his wave paintings, and [Hiroshige](/source/Hiroshige).[26]

In 1799 a French chemist, [Louis Jacques Thénard](/source/Louis_Jacques_Th%C3%A9nard), made a synthetic cobalt blue pigment which became immensely popular with painters.

In 1824 the [Societé pour l'Encouragement d'Industrie](/source/Societ%C3%A9_pour_l'Encouragement_d'Industrie) in France offered a prize for the invention of an artificial [ultramarine](/source/Ultramarine) which could rival the natural colour made from lapis lazuli. The prize was won in 1826 by a chemist named Jean Baptiste Guimet, but he refused to reveal the formula of his colour. In 1828, another scientist, [Christian Gmelin](/source/Christian_Gmelin) then a professor of chemistry in Tübingen, found the process and published his formula. This was the beginning of new industry to manufacture artificial ultramarine, which eventually almost completely replaced the natural product.[27]

In 1878 the German chemistry and dyeing company Badische Anilin- und Soda-Fabrik (BASF) headed by chemist Adolf von Baeyer synthesised [indigo](/source/Indigo_dye).[28] This product rapidly replaced natural indigo, wiping out vast farms growing indigo. It is now the blue of blue jeans. As the pace of [organic chemistry](/source/Organic_chemistry) accelerated, a succession of synthetic blue dyes were discovered including [Indanthrone blue](/source/Indanthrone_blue), which had even greater resistance to fading during washing or in the sun, and [copper phthalocyanine](/source/Copper_phthalocyanine). BASF's work on Indanthrone blue had been a by product of their 17 year research on synthesizing Indigo and the version "Indigo Pure BASF" which would be commercially produced before Indanthrene blue would take over popularity.[29]

		- *[The Blue Boy](/source/The_Blue_Boy)* (1770), featuring lapis lazuli, indigo, and cobalt colourants,[30]

		- *[The Great Wave off Kanagawa](/source/The_Great_Wave_off_Kanagawa)* illustrates the use of [Prussian blue](/source/Prussian_blue)

		- A synthetic indigo dye factory in Germany in 1890.

### Dyes for textiles and food

[31] [Woad](/source/Woad) and [true indigo](/source/Indigofera_tinctoria) were once used but since the early 1900s, all indigo is synthetic. Produced on an industrial scale, indigo is the blue of blue jeans. Blue dyes are organic compounds, both synthetic and natural.

For food, the triarylmethane dye [Brilliant blue FCF](/source/Brilliant_blue_FCF) is used for candies. The search continues for stable, natural blue dyes suitable for the food industry.[31]

Various [raspberry](/source/Raspberry)-flavoured foods are dyed blue. This was done to distinguish it from [strawberry](/source/Strawberry), [watermelon](/source/Watermelon) and [cherry](/source/Cherry)-flavoured foods.[32] The company [ICEE](/source/The_Icee_Company) used Blue No. 1 for their blue raspberry ICEEs.

		- Blue raspberry frozen yogurt with white chocolate chips, coconut, and cherries.

		- Blue haribo jelly beans. Raspberry flavour.

		- A blue raspberry-flavoured Jolly Rancher Hard Candy Stix.

		- Chemical structure of [indigo dye](/source/Indigo_dye), a widely produced blue dye. [Blue jeans](/source/Jeans) consist of 1–3% by weight of this [organic compound](/source/Organic_compound).

		- Chemical structure of C.I. Acid Blue 9, a dye commonly used in candies.

### Pigments for painting and glass

See also: [Blue pigments](/source/Blue_pigments)

Blue [pigments](/source/Pigment) were once produced from minerals, especially [lapis lazuli](/source/Lapis_lazuli) and its close relative [ultramarine](/source/Ultramarine). These minerals were crushed, ground into powder, and then mixed with a quick-drying binding agent, such as egg yolk ([tempera painting](/source/Tempera)); or with a slow-drying oil, such as [linseed oil](/source/Linseed_oil), for [oil painting](/source/Oil_painting). Two inorganic but synthetic blue pigments are [cerulean blue](/source/Cerulean) (primarily cobalt(II) stanate: Co2SnO4) and [Prussian blue](/source/Prussian_blue) (milori blue: primarily Fe7(CN)18). The chromophore in blue [glass](/source/Glass) and glazes is [cobalt](/source/Cobalt)(II). Diverse cobalt(II) salts such as cobalt carbonate or cobalt(II) aluminate are mixed with the silica prior to firing. The cobalt occupies sites otherwise filled with silicon.

### Inks

[Methyl blue](/source/Methyl_blue) is the dominant blue pigment in inks used in pens.[33] [Blueprinting](/source/Blueprint) involves the production of [Prussian blue](/source/Prussian_blue) in situ.

### Inorganic compounds

CuSO4.5H2O

[Anhydrous](/source/Anhydrous) cobalt(II) chloride

[Vanadyl sulphate](/source/Vanadyl_sulfate)

Certain metal [ions](/source/Ion) characteristically form blue solutions or blue salts. Of some practical importance, [cobalt](/source/Cobalt) is used to make the deep blue glazes and glasses. It substitutes for [silicon](/source/Silicon) or [aluminium](/source/Aluminium) ions in these materials. Cobalt is the blue [chromophore](/source/Chromophore) in [stained glass windows](/source/Stained_glass), such as those in [Gothic cathedrals](/source/Gothic_cathedrals_and_churches) and in Chinese [porcelain](/source/Porcelain) beginning in the [Tang dynasty](/source/Tang_dynasty). [Copper(II)](/source/Copper#Compounds) (Cu2+) also produces many blue compounds, including the commercial [algicide](/source/Algaecide) [copper(II) sulphate](/source/Copper(II)_sulfate) (CuSO4.5H2O). Similarly, [vanadyl](/source/Vanadyl_ion) salts and solutions are often blue, e.g. [vanadyl sulphate](/source/Vanadyl_sulfate).

## In nature

### Sky and sea

Further information: [Rayleigh scattering](/source/Rayleigh_scattering) and [Why is the sky blue?](/source/Why_is_the_sky_blue%3F)

When sunlight passes through the atmosphere, the blue wavelengths are scattered more widely by the oxygen and nitrogen molecules, and more blue comes to our eyes. This effect is called [Rayleigh scattering](/source/Rayleigh_scattering), after [Lord Rayleigh](/source/Lord_Rayleigh) and confirmed by [Albert Einstein](/source/Albert_Einstein) in 1911.[34][35]

The sea is seen as blue for largely the same reason: the water absorbs the longer wavelengths of red and reflects and scatters the blue, which comes to the eye of the viewer. The deeper the observer goes, the darker the blue becomes. In the open sea, only about 1% of light penetrates to a depth of 200 metres (see [underwater](/source/Underwater) and [euphotic depth](/source/Euphotic_depth)).

The colour of the sea is also affected by the colour of the sky, reflected by particles in the water; and by [algae](/source/Algae) and plant life in the water, which can make it look green; or by sediment, which can make it look brown.[36]

The farther away an object is, the more blue it often appears to the eye. For example, mountains in the distance often appear blue. This is the effect of [atmospheric perspective](/source/Atmospheric_perspective); the farther an object is away from the viewer, the less contrast there is between the object and its background colour, which is usually blue. In a painting where different parts of the composition are blue, green and red, the blue will appear to be more distant, and the red closer to the viewer. The cooler a colour is, the more distant it seems.[37] Blue light is [scattered more](/source/Rayleigh_scattering) than other wavelengths by the gases in the [atmosphere](/source/Atmosphere), hence our "blue planet".

		- Earth's blue [halo](/source/Halo_(optical_phenomenon)) when seen from space

		- Another example of [Rayleigh scattering](/source/Rayleigh_scattering)

		- The sea

### Minerals

		- [Lapis-lazuli](/source/Lapis-lazuli)

		- [Azurite](/source/Azurite)

		- Natural [ultramarine](/source/Ultramarine) pigment

		- [Logan sapphire](/source/Logan_sapphire)

Some of the most desirable gems are blue, including [sapphire](/source/Sapphire) and [tanzanite](/source/Tanzanite). Compounds of copper(II) are characteristically blue and so are many copper-containing minerals. [Azurite](/source/Azurite) (Cu3(CO3)2(OH)2), with a deep blue colour, was once employed in medieval years, but it is unstable pigment, losing its colour especially under dry conditions. [Lapis lazuli](/source/Lapis_lazuli), mined in Afghanistan for more than three thousand years, was used for jewellery and ornaments, and later was crushed and powdered and used as a pigment. The more it was ground, the lighter the blue colour became. Natural [ultramarine](/source/Ultramarine), made by grinding lapis lazuli into a fine powder, was the finest available blue pigment in the Middle Ages and the [Renaissance](/source/Renaissance). It was extremely expensive, and in [Italian Renaissance](/source/Italian_Renaissance) art, it was often reserved for the robes of the [Virgin Mary](/source/Virgin_Mary).

### Plants and fungi

See also: [Basics of blue flower colouration](/source/Basics_of_blue_flower_colouration)

		- *Primula acaulis*

		- Morning glory (*[Ipomoea acuminata](/source/Ipomoea_acuminata)*)

		- *[Vaccinium corymbosum](/source/Vaccinium_corymbosum)*

		- *[Vinca minor](/source/Vinca_minor)*

		- Blue Delphinium flower

		- Blue Lupme flower *[Lupinus pilosus](/source/Lupinus_pilosus)*

		- *[Lactarius indigo](/source/Lactarius_indigo)*[38]

Intense efforts have focused on blue flowers and the possibility that natural blue colourants could be used as food dyes.[31] Commonly, blue colours in plants are [anthocyanins](/source/Anthocyanin): "the largest group of water-soluble pigments found widespread in the plant kingdom".[39] In the few plants that exploit structural colouration, brilliant colours are produced by structures within cells. The most brilliant blue colouration known in any living tissue is found in the marble berries of *[Pollia condensata](/source/Pollia_condensata)*, where a spiral structure of cellulose fibrils scattering blue light. The fruit of [quandong](/source/Quandong) (*Santalum acuminatum*) can appear blue owing to the same effect.[31]

### Animals

		- [Morpho butterfly](/source/Morpho_butterfly)

		- [Indigo buntings](/source/Indigo_bunting) have iridescent feathers.

		- Blue facial ridges of [mandrill](/source/Mandrill)

		- [Blue poison dart frog](/source/Blue_poison_dart_frog)

		- The [mandarin fish](/source/Synchiropus_splendidus) is one of few animal species with blue pigment

Blue-pigmented animals are relatively rare.[40] Examples of which include butterflies of the genus *[Nessaea](/source/Nessaea)*, where blue is created by [pterobilin](/source/Pterobilin).[41] Other blue pigments of animal origin include phorcabilin, used by other butterflies in *[Graphium](/source/Graphium_(butterfly))* and *[Papilio](/source/Papilio)* (specifically *[P. phorcas](/source/Papilio_phorcas)* and *[P. weiskei](/source/Papilio_weiskei)*), and sarpedobilin, which is used by *[Graphium sarpedon](/source/Graphium_sarpedon)*.[42] Blue-pigmented [organelles](/source/Organelles), known as "cyanosomes", exist in the [chromatophores](/source/Chromatophore) of at least two fish species, the [mandarin fish](/source/Synchiropus_splendidus) and the [picturesque dragonet](/source/Picturesque_dragonet).[43] More commonly, blueness in animals is a [structural colouration](/source/Structural_color); an optical interference effect induced by organised nanometre-sized scales or fibres. Examples include the plumage of several birds like the [blue jay](/source/Blue_jay) and [indigo bunting](/source/Indigo_bunting),[44] the scales of butterflies like the [morpho butterfly](/source/Morpho_butterfly),[45] [collagen](/source/Collagen) fibres in the skin of some species of monkey and [opossum](/source/Opossum),[46] and the [iridophore](/source/Chromatophore#Iridophores_and_leucophores) cells in some fish and frogs.[47][48]

### Eyes

Main article: [Eye colour § Blue](/source/Eye_colour#Blue)

Blue eyes actually contain no blue pigment. The colour is caused by an effect called [Tyndall scattering](/source/Tyndall_effect).

Blue eyes do not actually contain any blue pigment. [Eye colour](/source/Eye_colour) is determined by two factors: the [pigmentation](/source/Pigment) of the eye's [iris](/source/Iris_(anatomy))[49][50] and the [scattering](/source/Scattering) of light by the [turbid](/source/Turbidity) medium in the [stroma of the iris](/source/Stroma_of_iris).[51] In humans, the pigmentation of the iris varies from light brown to black. The appearance of blue, green, and hazel eyes results from the [Tyndall scattering](/source/Tyndall_effect) of light in the stroma, an optical effect similar to what accounts for the blueness of the sky.[51][52] The irises of the eyes of people with blue eyes contain less dark [melanin](/source/Melanin) than those of people with brown eyes, which means that they absorb less short-wavelength blue light, which is instead reflected out to the viewer. Eye colour also varies depending on the lighting conditions, especially for lighter-coloured eyes.

Blue eyes are most common in Ireland, the [Baltic Sea](/source/Baltic_Sea) area and [Northern Europe](/source/Northern_Europe),[53] and are also found in [Eastern](/source/Eastern_Europe), [Central](/source/Central_Europe), and [Southern Europe](/source/Southern_Europe). Blue eyes are also found in parts of [Western Asia](/source/Western_Asia), most notably in [Afghanistan](/source/Afghanistan), [Syria](/source/Syria), [Iraq](/source/Iraq), and [Iran](/source/Iran).[54] In [Estonia](/source/Estonia), 99% of people have blue eyes.[55][56] In [Denmark](/source/Denmark) in 1978, only 8% of the population had brown eyes, though through immigration, today that number is about 11%.[56] In [Germany](/source/Germany), about 75% have blue eyes.[56]

In the United States, as of 2006, 1 out of every 6 people, or 16.6% of the total population, and 22.3% of the [white population](/source/White_Americans), have blue eyes, compared with about half of Americans born in 1900, and a third of Americans born in 1950. Blue eyes are becoming less common among American children. In the US, males are 3–5% more likely to have blue eyes than females.[53]

## History

See also: [Blue in culture](/source/Blue_in_culture)

### In the ancient world

		- [Lapis lazuli](/source/Lapis_lazuli) bowl from Iran, end of 3rd – beginning of 2nd millennium BC (Louvre Museum)

		- [Egyptian blue](/source/Egyptian_blue) tripodic beaker imitating lapis lazuli. South Mesopotamia. (1399-1200 BC)

		- Fresco of Polyphemus and Galatea, Pompei, using [Egyptian blue](/source/Egyptian_blue) (1st c. BC) (Metropolitan Museum)

As early as the [7th millennium BC](/source/7th_millennium_BC), lapis lazuli was mined in the [Sar-i Sang](/source/Sar-i_Sang) mines,[57] in [Shortugai](/source/Shortugai), and in other mines in [Badakhshan](/source/Badakhshan) province in northeast [Afghanistan](/source/Afghanistan).[58]

Lapis lazuli artefacts, dated to 7570 BC, have been found at [Bhirrana](/source/Bhirrana), which is the oldest site of [Indus Valley civilisation](/source/Indus_Valley_civilisation).[59] Lapis was highly valued by the Indus Valley Civilisation (7570–1900 BC).[59][60][61] Lapis beads have been found at [Neolithic](/source/Neolithic) burials in [Mehrgarh](/source/Mehrgarh), the [Caucasus](/source/Caucasus), and as far away as [Mauritania](/source/Mauritania).[62] It was used in the [funeral mask of Tutankhamun](/source/Tutankhamun's_mask) (1341–1323 BC).[63]

A term for Blue was relatively rare in many forms of ancient art and decoration, and even in ancient literature. The Ancient Greek poets described the sea as green, brown or "the colour of wine". The colour is mentioned several times in the [Hebrew Bible](/source/Hebrew_Bible) as '[tekhelet](/source/Tekhelet)'. Reds, blacks, browns, and ochres are found in [cave paintings](/source/Cave_painting) from the Upper [Paleolithic](/source/Paleolithic) period, but not blue. Blue was also not used for dyeing fabric until long after red, ochre, pink, and purple. This is probably due to the perennial difficulty of making blue dyes and pigments. On the other hand, the rarity of blue pigment made it even more valuable.[64]

The earliest known blue dyes were made from plants – [woad](/source/Woad) in Europe, [indigo](/source/Indigo_dye) in Asia and Africa, while blue pigments were made from minerals, usually either [lapis lazuli](/source/Lapis_lazuli) or [azurite](/source/Azurite), and required more.[65] Blue glazes posed still another challenge since the early blue dyes and pigments were not thermally robust. In c. 2500 BC, the blue glaze [Egyptian blue](/source/Egyptian_blue) was introduced for ceramics, as well as many other objects.[66][67] The Greeks imported indigo dye from India, calling it indikon, and they painted with Egyptian blue. Blue was not one of the four primary colours for Greek painting described by [Pliny the Elder](/source/Pliny_the_Elder) (red, yellow, black, and white). For the Romans, blue was the colour of mourning, as well as the colour of barbarians. The Celts and Germans reportedly dyed their faces blue to frighten their enemies, and tinted their hair blue when they grew old.[68] The Romans made extensive use of indigo and Egyptian blue pigment, as evidenced, in part, by frescos in [Pompeii](/source/Pompeii). The Romans had many words for varieties of blue, including *caeruleus*, *caesius*, *glaucus*, *cyaneus*, *lividus*, *venetus*, *aerius*, and *ferreus*, but two words, both of foreign origin, became the most enduring; *blavus*, from the Germanic word *blau*, which eventually became *bleu* or blue; and *azureus*, from the Arabic word *lazaward*, which became azure.[69]

Blue was widely used in the decoration of churches in the Byzantine Empire.[70] By contrast, in the Islamic world, blue was of secondary to green, believed to be the favourite colour of the [Prophet Mohammed](/source/Muhammad). At certain times in [Moorish Spain](/source/Al-Andalus) and other parts of the Islamic world, blue was the colour worn by Christians and Jews, because only Muslims were allowed to wear white and green.[71]

### In the Middle Ages

		- Stained glass window at [Saint Denis Basilica](/source/Saint_Denis_Basilica) (1130–1140), coloured with [cobalt blue](/source/Cobalt_blue)

		- Detail of the Blue Virgin Window, [Chartres Cathedral](/source/Chartres_Cathedral) (12th c.)

		- The [Wilton Diptych](/source/Wilton_Diptych) (1395–1399). The [Virgin Mary](/source/Virgin_Mary) was traditionally shown in blue(14th c.)

In the art and life of Europe during the early [Middle Ages](/source/Middle_Ages), blue played a minor role. This changed dramatically between 1130 and 1140 in Paris, when the [Abbe Suger](/source/Abbe_Suger) rebuilt the [Saint Denis Basilica](/source/Saint_Denis_Basilica). Suger considered that light was the visible manifestation of the Holy Spirit.[72] He installed [stained glass](/source/Stained_glass) windows coloured with [cobalt](/source/Cobalt), which, combined with the light from the red glass, filled the church with a bluish violet light. The church became the marvel of the [Christian world](/source/Christian_world), and the colour became known as the *"bleu de Saint-Denis"*. In the years that followed even more elegant blue stained glass windows were installed in other churches, including at [Chartres Cathedral](/source/Chartres_Cathedral) and [Sainte-Chapelle](/source/Sainte-Chapelle) in Paris.[73]

In the 12th century the Roman Catholic Church dictated that painters in Italy (and the rest of Europe consequently) to paint the Virgin Mary with blue, which became associated with holiness, humility and virtue. In medieval paintings, blue was used to attract the attention of the viewer to the Virgin Mary. Paintings of the mythical [King Arthur](/source/King_Arthur) began to show him dressed in blue. The coat of arms of the kings of France became an azure or light blue shield, sprinkled with golden [fleur-de-lis](/source/Fleur-de-lis) or lilies. Blue had come from obscurity to become the royal colour.[74]

### Renaissance through 18th century

Blue came into wider use beginning in the Renaissance, when artists began to paint the world with perspective, depth, shadows, and light from a single source. In Renaissance paintings, artists tried to create harmonies between blue and red, lightening the blue with lead white paint and adding shadows and highlights. [Raphael](/source/Raphael) was a master of this technique, carefully balancing the reds and the blues so no one colour dominated the picture.[75]

[Ultramarine](/source/Ultramarine) was the most prestigious blue of the Renaissance, being more expensive than gold. Wealthy art patrons commissioned works with the most expensive blues possible. In 1616 [Richard Sackville](/source/Richard_Sackville%2C_3rd_Earl_of_Dorset) commissioned a portrait of himself by [Isaac Oliver](/source/Isaac_Oliver) with three different blues, including ultramarine pigment for his stockings.[76]

		- Portrait of Richard Sackville (1616), using three expensive blues, including ultramarine for his stockings

		- [Ming dynasty](/source/Ming_dynasty), Porcelain vase painted with cobalt blue under transparent glaze. (15th c.) (Metropolitan Museum)

		- [Delftware](/source/Delftware) plaque with cobalt blue painting (1683) (Rijksmuseum, Amsterdam)

		- Portrait of King [Louis XIV](/source/Louis_XIV) in coronation robes, by [Hyacinthe Rigaud](/source/Hyacinthe_Rigaud) (c. 1700) (Louvre Museum)

		- Urn by [Josiah Wedgwood](/source/Josiah_Wedgwood) (1780s) (Metropolitan Museum)

		- Queen [Maria I of Portugal](/source/Maria_I_of_Portugal) (late 1700s)

		- *[Girl with a Pearl Earring](/source/Girl_with_a_Pearl_Earring)* by [Johannes Vermeer](/source/Johannes_Vermeer) features [ultramarine](/source/Ultramarine) pigment

An industry for the manufacture of fine blue and white pottery began in the 14th century in [Jingdezhen](/source/Jingdezhen), China, using white Chinese porcelain decorated with patterns of [cobalt blue](/source/Cobalt_blue), imported from Persia. It was first made for the family of the Emperor of China, then was exported around the world, with designs for export adapted to European subjects and tastes. The Chinese blue style was also adapted by Dutch craftsmen in [Delft](/source/Delftware) and English craftsmen in [Staffordshire](/source/Staffordshire) in the 17th-18th centuries. in the 18th century, blue and white porcelains were produced by [Josiah Wedgwood](/source/Josiah_Wedgwood) and other British craftsmen.[77]

### 19th-20th century

		- [Beau Brummell](/source/Beau_Brummell) (1776–1840) introduced the ancestor of the modern blue suit

		- Queen [Maria II of Portugal](/source/Maria_II_of_Portugal) in a blue and [gold embroidered](/source/Goldwork_(embroidery)) gown (1835)

		- A California gold miner in blue jeans (1853)

		- [Isabel, Princess Imperial of Brazil](/source/Isabel%2C_Princess_Imperial_of_Brazil) in light blue gown (1853)

		- New York City police in 1871

The early 19th century saw the ancestor of the modern blue business suit, created by [Beau Brummell](/source/Beau_Brummell) (1776–1840), who set fashion at the London Court. It also saw the invention of [blue jeans](/source/Blue_jeans), a highly popular form of workers's costume, invented in 1853 by [Jacob W. Davis](/source/Jacob_W._Davis) who used metal rivets to strengthen blue [denim](/source/Denim) work clothing in the California gold fields. The invention was funded by San Francisco entrepreneur [Levi Strauss](/source/Levi_Strauss), and spread around the world.[78]

		- Van Gogh's *[Starry Night Over the Rhône](/source/Starry_Night_Over_the_Rh%C3%B4ne)* (1888). Blue used to create a mood or atmosphere. A cobalt blue sky, and cobalt or ultramarine water.

		- *[The Conversation](/source/The_Conversation_(Matisse))* by [Henri Matisse](/source/Henri_Matisse) (1908–1912)

Recognising the emotional power of blue, many artists made it the central element of paintings in the 19th and 20th centuries. They included [Pablo Picasso](/source/Picasso's_Blue_Period), [Pavel Kuznetsov](/source/Pavel_Kuznetsov) and the [Blue Rose](/source/Blue_Rose_(art_group)) art group, and [Kandinsky](/source/Wassily_Kandinsky) and [Der Blaue Reiter](/source/Der_Blaue_Reiter) (The Blue Rider) school.[79] [Henri Matisse](/source/Henri_Matisse) expressed deep emotions with blue, "A certain blue penetrates your soul."[80] In the second half of the 20th century, painters of the [abstract expressionist](/source/Abstract_expressionist) movement use blues to inspire ideas and emotions. Painter [Mark Rothko](/source/Mark_Rothko) observed that colour was "only an instrument;" his interest was "in expressing human emotions tragedy, ecstasy, doom, and so on".[81]

## In society and culture

Main article: [Blue in culture](/source/Blue_in_culture)

### Uniforms

		- [Navy blue](/source/Navy_blue) derives its name from the uniform of [Royal Navy](/source/Royal_Navy) officers

		- [Transportation Security Administration](/source/Transportation_Security_Administration) agents

		- Ukrainian police officer in Donetsk

		- Officers of the [Military Police of Rio de Janeiro State](/source/Military_Police_of_Rio_de_Janeiro_State), Brazil

In the 17th century. The Prince-Elector of Brandenburg, [Frederick William I of Prussia](/source/Frederick_William_I_of_Prussia), chose [Prussian blue](/source/Prussian_blue) as the new colour of Prussian military uniforms, because it was made with [Woad](/source/Woad), a local crop, rather than [Indigo](/source/Indigo), which was produced by the colonies of Brandenburg's rival, England. It was worn by the German army until World War I, with the exception of the soldiers of Bavaria, who wore sky-blue.[82]

In 1748, the [Royal Navy](/source/Royal_Navy) adopted a dark shade of blue for the uniform of officers.[78] It was first known as marine blue, now known as [navy blue](/source/Navy_blue).[83] The militia organised by [George Washington](/source/George_Washington) selected blue and [buff](/source/Buff_(colour)), the colours of the British [Whig Party](/source/Whig_(British_political_party)). Blue continued to be the colour of the field uniform of the US Army until 1902, and is still the colour of the dress uniform.[84]

In the 19th century, police in the United Kingdom, including the [Metropolitan Police](/source/Metropolitan_Police) and the [City of London Police](/source/City_of_London_Police) also adopted a navy blue uniform. Similar traditions were embraced in France and Austria.[85] It was also adopted at about the same time for the uniforms of the officers of the [New York City Police Department](/source/New_York_City_Police_Department).[78]

### Gender

See also: [Gendered associations of pink and blue](/source/Gendered_associations_of_pink_and_blue)

Blue is used to represent [males](/source/Male). Beginning as a trend the mid-19th century and applying primarily to clothing, gendered associations with blue became more widespread from the 1950s. The colour became associated with males after [World War II](/source/World_War_II).[86]

		- This restroom sign on an [All Nippon Airways](/source/All_Nippon_Airways) Boeing 767-300 uses pink for the female gender and blue for the male gender.

		- Cake using blue to represent the male sex.

		- Baby blue newborn male clothing

### Religion

		- In [Hinduism](/source/Hinduism), [Krishna](/source/Krishna) is depicted with blue skin

		- Blue domes of the Church dedicated to St. Spirou in Firostefani, [Santorini](/source/Santorini) island (Thira), Greece.

		- Persian blue in [Shah mosque](/source/Shah_mosque) (16th c.) in [Isfahan](/source/Isfahan), Iran

- [Blue in Judaism](/source/Blue_in_Judaism): In the [Torah](/source/Torah),[87] the [Israelites](/source/Israelites) were commanded to put fringes, *[tzitzit](/source/Tzitzit)*, on the corners of their garments, and to weave within these fringes a "twisted thread of blue (*tekhelet*)".[88] In ancient days, this blue thread was made from a dye extracted from a Mediterranean snail called the *hilazon*. [Maimonides](/source/Maimonides) claimed that this blue was the colour of "the clear noonday sky"; [Rashi](/source/Rashi), the colour of the evening sky.[89] According to several rabbinic sages, blue is the colour of God's Glory.[90] Staring at this colour aids in mediation, bringing us a glimpse of the "pavement of sapphire, like the very sky for purity", which is a likeness of the Throne of God.[91] (The [Hebrew](/source/Hebrew_language) word for glory) Many items in the *[Mishkan](/source/Mishkan)*, the portable sanctuary in the wilderness, such as the *[menorah](/source/Menorah_(Temple))*, many of the vessels, and the [Ark of the Covenant](/source/Ark_of_the_Covenant), were covered with blue cloth when transported from place to place.[92]

- Blue in [Christianity](/source/Christianity): Blue is particularly associated with the [Virgin Mary](/source/Mary_(mother_of_Jesus)). This was the result of a decree of [Pope Gregory I](/source/Pope_Gregory_I) (540–601) who ordered that all religious paintings should tell a story which was clearly comprehensible to all viewers, and that figures should be easily recognisable, especially that of the figure of Mary. If she was alone in the image, her costume was usually painted with the finest blue, [ultramarine](/source/Ultramarine). If she was with Christ, her costume was usually painted with a less expensive pigment, to avoid outshining him.[93][94][95][96]

- Blue in [Hinduism](/source/Hinduism): Many of the gods are depicted as having blue-coloured skin, particularly those associated with [Vishnu](/source/Vishnu), who is said to be the preserver of the world, and thus intimately connected to water. [Krishna](/source/Krishna) and [Rama](/source/Rama), Vishnu's avatars, are usually depicted with blue skin. [Shiva](/source/Shiva), the destroyer deity, is also depicted in a light-blue hue, and is called *[Nīlakaṇṭha](/source/Nilakanta_(Hinduism))*, or blue-throated, for having swallowed poison to save the universe during the [Samudra Manthana](/source/Samudra_Manthana), the churning of the ocean of milk. Blue is used to symbolically represent the fifth, and the throat, [chakra](/source/Chakra) ([Vishuddha](/source/Vishuddha)).[97]

- Blue in [Sikhism](/source/Sikhism): The [Akali Nihangs](/source/Nihang) warriors wear all-blue attire. [Guru Gobind Singh](/source/Guru_Gobind_Singh) also has a [blue roan](/source/Roan_(horse)) [horse](/source/Horse). The Sikh Rehat Maryada states that the [Nishan Sahib](/source/Nishan_Sahib) hoisted outside every [Gurudwara](/source/Gurdwara) should be [xanthic](/source/Yellow) (Basanti in [Punjabi](/source/Punjabi_language)) or greyish blue (modern day [navy blue](/source/Navy_blue)) (Surmaaee in [Punjabi](/source/Punjabi_language)) colour.[98][99]

### Sports

		- The [Italian national football team](/source/Italy_national_football_team)

		- Serbian national volleyball team, 2012 Olympics

		- Basketball player for the Blue Devils at Cassell Coliseum

In sports, blue is widely represented in uniforms in part because the majority of national teams wear the colours of their national flag. For example, the national men's football team of [France](/source/France_national_football_team) are known as *Les Bleus* (the Blues). Similarly, [Argentina](/source/Argentina_national_football_team), [Italy](/source/Italy_national_football_team), and [Uruguay](/source/Uruguay_national_football_team) wear blue shirts.[100] The [Asian Football Confederation](/source/Asian_Football_Confederation) and the [Oceania Football Confederation](/source/Oceania_Football_Confederation) use blue text on their logos. Blue is well represented in [baseball](/source/Baseball) ([Blue Jays](/source/Toronto_Blue_Jays)), [basketball](/source/National_Basketball_Association), and [American football](/source/National_Football_League), and [ice hockey](/source/National_Hockey_League). The [Indian national cricket team](/source/India_national_cricket_team) wears blue uniform during [One day international](/source/One_day_international) matches, as such the team is also referred to as "Men in Blue".[101]

### Politics

		- Flag of the [United Nations](/source/United_Nations), approximates "sky blue"

		- Flag of the [European Union](/source/European_Union) is "reflex blue", a medium dark blue

		- A presidential-election map of the US, 2008–2020. States that consistently vote for Democrats are termed "blue states".

Unlike red or green, blue was not strongly associated with any particular country, religion or political movement. As the colour of harmony, it was chosen as the colour for the flags of the [United Nations](/source/United_Nations), the [European Union](/source/European_Union), and [NATO](/source/NATO).[102] In politics, blue is often used as the colour of conservative parties, contrasting with the red associated with left-wing parties.[103] Some conservative parties that use the colour blue include the [Conservative Party (UK)](/source/Conservative_Party_(UK)),[104] [Conservative Party of Canada](/source/Conservative_Party_of_Canada),[105] [Liberal Party of Australia](/source/Liberal_Party_of_Australia),[106] [Liberal Party of Brazil](/source/Liberal_Party_(Brazil%2C_2006)), and [Likud](/source/Likud) of Israel.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] However, in some countries, blue is not associated main conservative party. In the United States, the liberal [Democratic Party](/source/Democratic_Party_(United_States)) is associated with blue, while the conservative [Republican Party](/source/Republican_Party_(United_States)) is associated with red. US states which have been won by the Democratic Party in four consecutive presidential elections are termed "blue states", while those that have been won by the Republican Party are termed "red states".[107] [South Korea](/source/South_Korea) also uses this colour model, with the [Democratic Party](/source/Democratic_Party_(South_Korea%2C_2015)) on the left using blue[108] and the [People Power Party](/source/People_Power_Party_(South_Korea)) on the right using red.

## See also

- [Engineer's blue](/source/Engineer's_blue)

- [Lists of colours](/source/Lists_of_colours)

- [Non-photo blue](/source/Non-photo_blue)

- [Blue pigments](/source/Blue_pigments)

- [All pages with titles beginning with *Blue*](https://en.wikipedia.org/wiki/Special:PrefixIndex/Blue)

- [All pages with titles containing *Blue*](https://en.wikipedia.org/wiki/Special:Search/intitle:%22Blue%22)

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1. **[^](#cite_ref-ExeterIridescence_24-0)** ["Iridescence in Lepidoptera"](https://web.archive.org/web/20140407082122/http://emps.exeter.ac.uk/physics-astronomy/research/emag/themes/natural-photonics/iridescenceinlepidoptera/). *Natural Photonics (originally in Physics Review Magazine)*. University of Exeter. September 1998. Archived from [the original](http://emps.exeter.ac.uk/physics-astronomy/research/emag/themes/natural-photonics/iridescenceinlepidoptera/) on 7 April 2014. Retrieved 27 April 2012.

1. **[^](#cite_ref-25)** Michel Pastoureau, *Bleu – Histoire d'une couleur*, pp. 114–16

1. **[^](#cite_ref-26)** Roger Keyes, *Japanese Woodblock Prints: A Catalogue of the Mary A. Ainsworth Collection*, R, Allen Memorial Art Museum, Oberlin College, 1984, p. 42, plate #140, p. 91 and catalogue entry #439, p. 185. for more on the story of Prussian blue in Japanese prints, see also the website of the Victoria and Albert Museum, London.

1. **[^](#cite_ref-27)** Maerz and Paul (1930). *A Dictionary of Color* New York: McGraw Hill p. 206

1. **[^](#cite_ref-28)** Clarkson, Philip S. Indigo MLB: a Handbook of the Practical Application of Synthetic Indigo. New York: H.A. Metz & co., 1904.

1. **[^](#cite_ref-29)** ["1865 – 1901 / The Age of Dyes"](https://www.basf.com/global/en/who-we-are/history/chronology/1865-1901). *BASF*. 15 April 2026. Retrieved 15 April 2026.

1. **[^](#cite_ref-30)** ["Eight blue moments in art history"](https://web.archive.org/web/20181016130010/https://www.tate.org.uk/context-comment/blogs/eight-blue-moments-art-history). The Tate. Archived from [the original](https://www.tate.org.uk/context-comment/blogs/eight-blue-moments-art-history) on 16 October 2018. Retrieved 16 October 2018.

1. ^ [***a***](#cite_ref-Ag_31-0) [***b***](#cite_ref-Ag_31-1) [***c***](#cite_ref-Ag_31-2) [***d***](#cite_ref-Ag_31-3) Newsome, Andrew G.; Culver, Catherine A.; Van Breemen, Richard B. (2014). "Nature's Palette: The Search for Natural Blue Colorants". *Journal of Agricultural and Food Chemistry*. **62** (28): 6498–6511. [Bibcode](/source/Bibcode_(identifier)):[2014JAFC...62.6498N](https://ui.adsabs.harvard.edu/abs/2014JAFC...62.6498N). [doi](/source/Doi_(identifier)):[10.1021/jf501419q](https://doi.org/10.1021%2Fjf501419q). [PMID](/source/PMID_(identifier)) [24930897](https://pubmed.ncbi.nlm.nih.gov/24930897).

1. **[^](#cite_ref-32)** ["You Need To Know The Truth About Blue Raspberry"](https://www.delish.com/food-news/a44272957/what-is-blue-raspberry/). *Delish*. 21 June 2023. Retrieved 22 October 2024.

1. **[^](#cite_ref-33)** Placke, Mina; Fischer, Norbert; Colditz, Michael; Kunkel, Ernst; Bohne, Karl-Heinz (2016). "Drawing and Writing Materials". *Ullmann's Encyclopedia of Industrial Chemistry*. pp. 1–12. [doi](/source/Doi_(identifier)):[10.1002/14356007.a09_037.pub2](https://doi.org/10.1002%2F14356007.a09_037.pub2). [ISBN](/source/ISBN_(identifier)) [978-3-527-30673-2](https://en.wikipedia.org/wiki/Special:BookSources/978-3-527-30673-2).

1. **[^](#cite_ref-34)** ["Why is the sky Blue?"](http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html). *ucr.edu*. [Archived](https://web.archive.org/web/20151102085211/http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html) from the original on 2 November 2015.

1. **[^](#cite_ref-35)** Glenn S. Smith (July 2005). ["Human color vision and the unsaturated blue color of the daytime sky"](http://www.patarnott.com/atms749/pdf/blueSkyHumanResponse.pdf) (PDF). *American Journal of Physics*. **73** (7): 590–597. [Bibcode](/source/Bibcode_(identifier)):[2005AmJPh..73..590S](https://ui.adsabs.harvard.edu/abs/2005AmJPh..73..590S). [doi](/source/Doi_(identifier)):[10.1119/1.1858479](https://doi.org/10.1119%2F1.1858479). [Archived](https://web.archive.org/web/20110715050855/http://www.patarnott.com/atms749/pdf/blueSkyHumanResponse.pdf) (PDF) from the original on 15 July 2011. Near sunrise and sunset, most of the light we see comes in nearly tangent to the Earth's surface, so that the light's path through the atmosphere is so long that much of the blue and even green light is scattered out, leaving the sun rays and the clouds it illuminates red. Therefore, when looking at the sunset and sunrise, the colour red is more perceptible than any of the other colours.

1. **[^](#cite_ref-36)** Anne Marie Helmenstine. ["Why Is the Ocean Blue?"](http://chemistry.about.com/od/waterchemistry/f/why-is-the-ocean-blue.htm). *About.com Education*. [Archived](https://web.archive.org/web/20121118203351/http://chemistry.about.com/od/waterchemistry/f/why-is-the-ocean-blue.htm) from the original on 18 November 2012.

1. **[^](#cite_ref-FOOTNOTEHeller200914_37-0)** [Heller 2009](#CITEREFHeller2009), p. 14.

1. **[^](#cite_ref-38)** Harmon, A. D.; Weisgraber, K. H.; Weiss, U. (1980). "Preformed azulene pigments of *Lactarius indigo* (Schw.) Fries (Russulaceae, Basidiomycetes)". *[Experientia](/source/Experientia)*. **36**: 54–56. [doi](/source/Doi_(identifier)):[10.1007/BF02003967](https://doi.org/10.1007%2FBF02003967). [S2CID](/source/S2CID_(identifier)) [21207966](https://api.semanticscholar.org/CorpusID:21207966).

1. **[^](#cite_ref-39)** Nuno Mateas, Victor de Freitas (2008). "Anthrocyanins as Food Colorants". In Gould, K.; Davies, K.; Winefield, C. (eds.). *Anthocyanins: Biosynthesis, Functions, and Applications*. Springer. p. 283. [ISBN](/source/ISBN_(identifier)) [978-0-387-77334-6](https://en.wikipedia.org/wiki/Special:BookSources/978-0-387-77334-6).

1. **[^](#cite_ref-40)** Umbers, Kate D. L. (2013). ["On the Perception, Production and Function of Blue Colouration in Animals"](https://doi.org/10.1111%2Fjzo.12001). *Journal of Zoology*. **289** (4): 229–242. [Bibcode](/source/Bibcode_(identifier)):[2013JZoo..289..229U](https://ui.adsabs.harvard.edu/abs/2013JZoo..289..229U). [doi](/source/Doi_(identifier)):[10.1111/jzo.12001](https://doi.org/10.1111%2Fjzo.12001).

1. **[^](#cite_ref-Vane-Wright_41-0)** Vane-Wright, Richard I. (22 February 1979). ["The coloration, identification and phylogeny of *Nessaea* butterflies (Lepidoptera: Nymphalidae)"](https://www.researchgate.net/publication/279190422). *Bulletin of the British Museum (Natural History)*. Entomology Series. **38** (2): 27–56. Retrieved 8 February 2018.

1. **[^](#cite_ref-Simonis_42-0)** Simonis, Priscilla; Serge, Berthier (30 March 2012). ["Chapter number 1 How Nature produces blue color"](https://www.researchgate.net/publication/258042644). In Massaro, Alessandro (ed.). *Photonic Crystals - Introduction, Applications and Theory*. InTech. [ISBN](/source/ISBN_(identifier)) [978-953-51-0431-5](https://en.wikipedia.org/wiki/Special:BookSources/978-953-51-0431-5). Retrieved 8 February 2018.

1. **[^](#cite_ref-43)** Goda, Makoto; Fujii, Ryozo (1995). ["Blue Chromatophores in Two Species of Callionymid Fish"](https://doi.org/10.2108%2Fzsj.12.811). *Zoological Science*. **12** (6): 811–813. [doi](/source/Doi_(identifier)):[10.2108/zsj.12.811](https://doi.org/10.2108%2Fzsj.12.811). [S2CID](/source/S2CID_(identifier)) [86385679](https://api.semanticscholar.org/CorpusID:86385679).

1. **[^](#cite_ref-44)** ["How Birds Make Colorful Feathers"](https://academy.allaboutbirds.org/how-birds-make-colorful-feathers/). 11 August 2015.

1. **[^](#cite_ref-45)** Potyrailo, Radislav A.; Bonam, Ravi K.; Hartley, John G.; Starkey, Timothy A.; Vukusic, Peter; Vasudev, Milana; Bunning, Timothy; Naik, Rajesh R.; Tang, Zhexiong; Palacios, Manuel A.; Larsen, Michael; Le Tarte, Laurie A.; Grande, James C.; Zhong, Sheng; Deng, Tao (2015). ["Towards outperforming conventional sensor arrays with fabricated individual photonic vapour sensors inspired by *Morpho* butterflies"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4569698). *Nature Communications*. **6** 7959. [Bibcode](/source/Bibcode_(identifier)):[2015NatCo...6.7959P](https://ui.adsabs.harvard.edu/abs/2015NatCo...6.7959P). [doi](/source/Doi_(identifier)):[10.1038/ncomms8959](https://doi.org/10.1038%2Fncomms8959). [PMC](/source/PMC_(identifier)) [4569698](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4569698). [PMID](/source/PMID_(identifier)) [26324320](https://pubmed.ncbi.nlm.nih.gov/26324320).

1. **[^](#cite_ref-Prum2004_46-0)** Prum RO, Torres RH (May 2004). ["Structural Colouration of Mammalian Skin: Convergent Evolution of Coherently Scattering Dermal Collagen Arrays"](http://jeb.biologists.org/content/207/12/2157.full.pdf) (PDF). *The Journal of Experimental Biology*. **207** (Pt 12): 2157–2172. [Bibcode](/source/Bibcode_(identifier)):[2004JExpB.207.2157P](https://ui.adsabs.harvard.edu/abs/2004JExpB.207.2157P). [doi](/source/Doi_(identifier)):[10.1242/jeb.00989](https://doi.org/10.1242%2Fjeb.00989). [hdl](/source/Hdl_(identifier)):[1808/1599](https://hdl.handle.net/1808%2F1599). [PMID](/source/PMID_(identifier)) [15143148](https://pubmed.ncbi.nlm.nih.gov/15143148). [S2CID](/source/S2CID_(identifier)) [8268610](https://api.semanticscholar.org/CorpusID:8268610). [Archived](https://ghostarchive.org/archive/20221009/http://jeb.biologists.org/content/207/12/2157.full.pdf) (PDF) from the original on 9 October 2022.

1. **[^](#cite_ref-47)** Ariel Rodríguez; Nicholas I. Mundy; Roberto Ibáñez; Heike Pröhl (2020). ["Being red, blue and green: the genetic basis of coloration differences in the strawberry poison frog (*Oophaga pumilio*)"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7158012). *BMC Genomics*. **21** (1): 301. [Bibcode](/source/Bibcode_(identifier)):[2020BMCG...21..301R](https://ui.adsabs.harvard.edu/abs/2020BMCG...21..301R). [doi](/source/Doi_(identifier)):[10.1186/s12864-020-6719-5](https://doi.org/10.1186%2Fs12864-020-6719-5). [PMC](/source/PMC_(identifier)) [7158012](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7158012). [PMID](/source/PMID_(identifier)) [32293261](https://pubmed.ncbi.nlm.nih.gov/32293261).

1. **[^](#cite_ref-48)** Makoto Goda; Ryozo Fujii (1998). ["The Blue Coloration of the Common Surgeonfish, Paracanthurus hepatus—II. Color Revelation and Color Changes"](https://doi.org/10.2108%2Fzsj.15.323). *Zoological Science*. **15** (3): 323–333. [doi](/source/Doi_(identifier)):[10.2108/zsj.15.323](https://doi.org/10.2108%2Fzsj.15.323). [PMID](/source/PMID_(identifier)) [18465994](https://pubmed.ncbi.nlm.nih.gov/18465994). [S2CID](/source/S2CID_(identifier)) [5860272](https://api.semanticscholar.org/CorpusID:5860272).

1. **[^](#cite_ref-Wielgus_49-0)** Wielgus AR, Sarna T (2005). ["Melanin in human irides of different color and age of donors"](https://ruj.uj.edu.pl/xmlui/handle/item/75157). *Pigment Cell Res*. **18** (6): 454–64. [doi](/source/Doi_(identifier)):[10.1111/j.1600-0749.2005.00268.x](https://doi.org/10.1111%2Fj.1600-0749.2005.00268.x). [PMID](/source/PMID_(identifier)) [16280011](https://pubmed.ncbi.nlm.nih.gov/16280011).

1. **[^](#cite_ref-Prota_50-0)** Prota G, Hu DN, Vincensi MR, McCormick SA, Napolitano A (1998). ["Characterization of melanins in human irides and cultured uveal melanocytes from eyes of different colors"](https://doi.org/10.1006%2Fexer.1998.0518). *Exp. Eye Res*. **67** (3): 293–99. [doi](/source/Doi_(identifier)):[10.1006/exer.1998.0518](https://doi.org/10.1006%2Fexer.1998.0518). [PMID](/source/PMID_(identifier)) [9778410](https://pubmed.ncbi.nlm.nih.gov/9778410).

1. ^ [***a***](#cite_ref-Fox_51-0) [***b***](#cite_ref-Fox_51-1) Fox, Denis Llewellyn (1979). [*Biochromy: Natural Coloration of Living Things*](https://books.google.com/books?id=c2xyxwlm2UkC&pg=PA9). University of California Press. p. 9. [ISBN](/source/ISBN_(identifier)) [978-0-520-03699-4](https://en.wikipedia.org/wiki/Special:BookSources/978-0-520-03699-4). [Archived](https://web.archive.org/web/20151003232604/https://books.google.com/books?id=c2xyxwlm2UkC&pg=PA9) from the original on 3 October 2015.

1. **[^](#cite_ref-Mason_52-0)** Mason, Clyde W. (1924). "Blue Eyes". *Journal of Physical Chemistry*. **28** (5): 498–501. [Bibcode](/source/Bibcode_(identifier)):[1924JPhCh..28..498M](https://ui.adsabs.harvard.edu/abs/1924JPhCh..28..498M). [doi](/source/Doi_(identifier)):[10.1021/j150239a007](https://doi.org/10.1021%2Fj150239a007).

1. ^ [***a***](#cite_ref-BostonGlobe_53-0) [***b***](#cite_ref-BostonGlobe_53-1) Douglas Belkin (17 October 2006). ["Don't it make my blue eyes brown Americans are seeing a dramatic color change"](http://archive.boston.com/news/globe/living/articles/2006/10/17/dont_it_make_my_blue_eyes_brown/). *The Boston Globe*. [Archived](https://web.archive.org/web/20120223022627/http://www.boston.com/yourlife/articles/2006/10/17/dont_it_make_my_blue_eyes_brown/) from the original on 23 February 2012.

1. **[^](#cite_ref-altervista1_54-0)** ["Pigmentation, the Pilous System, and Morphology of the Soft Parts"](https://web.archive.org/web/20110726095519/http://carnby.altervista.org/troe/08-05.htm). *altervista.org*. Archived from [the original](http://carnby.altervista.org/troe/08-05.htm) on 26 July 2011.

1. **[^](#cite_ref-55)** statement by Hans Eiberg from the Department of Cellular and Molecular Medicine at the [University of Copenhagen](/source/University_of_Copenhagen)

1. ^ [***a***](#cite_ref-More_than_56-0) [***b***](#cite_ref-More_than_56-1) [***c***](#cite_ref-More_than_56-2) Weise, Elizabeth (5 February 2008). ["More than meets the blue eye: You may all be related"](https://web.archive.org/web/20120910205153/http://www.usatoday.com/news/health/2008-02-05-blue-eyes_N.htm). *USA TODAY*. Archived from [the original](https://www.usatoday.com/news/health/2008-02-05-blue-eyes_N.htm) on 10 September 2012. Retrieved 23 December 2011.

1. **[^](#cite_ref-Ashok_Roy_2009_57-0)** David Bomford and Ashok Roy, *A Closer Look- Colour* (2009), National Gallery Company, London, ([ISBN](/source/ISBN_(identifier)) [978-1-85709-442-8](https://en.wikipedia.org/wiki/Special:BookSources/978-1-85709-442-8))

1. **[^](#cite_ref-58)** Moorey, Peter Roger (1999). [*Ancient Mesopotamian Materials and Industries: the Archaeological Evidence*](https://books.google.com/books?id=P_Ixuott4doC&q=Lapis+lazuli+++mines+in+the+Badakhshan&pg=PA86). Eisenbrauns. pp. 86–87. [ISBN](/source/ISBN_(identifier)) [978-1-57506-042-2](https://en.wikipedia.org/wiki/Special:BookSources/978-1-57506-042-2).

1. ^ [***a***](#cite_ref-lapis_59-0) [***b***](#cite_ref-lapis_59-1) ["Excavation Bhirrana | ASI Nagpur"](https://web.archive.org/web/20200804104933/http://excnagasi.in/excavation_bhirrana.html). *excnagasi.in*. Archived from [the original](http://excnagasi.in/excavation_bhirrana.html) on 4 August 2020. Retrieved 21 August 2020.

1. **[^](#cite_ref-60)** Sarkar, Anindya; Mukherjee, Arati Deshpande; Bera, M. K.; Das, B.; Juyal, Navin; Morthekai, P.; Deshpande, R. D.; Shinde, V. S.; Rao, L. S. (25 May 2016). ["Oxygen isotope in archaeological bioapatites from India: Implications to climate change and decline of Bronze Age Harappan civilization"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4879637). *Scientific Reports*. **6** (1) 26555. [Bibcode](/source/Bibcode_(identifier)):[2016NatSR...626555S](https://ui.adsabs.harvard.edu/abs/2016NatSR...626555S). [doi](/source/Doi_(identifier)):[10.1038/srep26555](https://doi.org/10.1038%2Fsrep26555). [ISSN](/source/ISSN_(identifier)) [2045-2322](https://search.worldcat.org/issn/2045-2322). [PMC](/source/PMC_(identifier)) [4879637](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4879637). [PMID](/source/PMID_(identifier)) [27222033](https://pubmed.ncbi.nlm.nih.gov/27222033). [S2CID](/source/S2CID_(identifier)) [4425978](https://api.semanticscholar.org/CorpusID:4425978).

1. **[^](#cite_ref-61)** DIKSHIT, K.N. (2012). "The Rise of Indian Civilization: Recent Archaeological Evidence from the Plains of 'Lost' River Saraswati and Radio-Metric Dates". *Bulletin of the Deccan College Research Institute*. 72/73: 1–42. [ISSN](/source/ISSN_(identifier)) [0045-9801](https://search.worldcat.org/issn/0045-9801). [JSTOR](/source/JSTOR_(identifier)) [43610686](https://www.jstor.org/stable/43610686).

1. **[^](#cite_ref-bc1995_62-0)** [Bowersox & Chamberlin 1995](#CITEREFBowersoxChamberlin1995)

1. **[^](#cite_ref-63)** Alessandro Bongioanni & Maria Croce

1. **[^](#cite_ref-64)** See [Pastoureau 2000](#CITEREFPastoureau2000), pp. 13–17.

1. **[^](#cite_ref-65)** Moorey, Peter Roger (1999). [*Ancient mesopotamian materials and industries: the archaeological evidence*](https://books.google.com/books?id=P_Ixuott4doC). Eisenbrauns. pp. [86](https://books.google.com/books?id=P_Ixuott4doC&pg=PA86)–[87](https://books.google.com/books?id=P_Ixuott4doC&pg=PA87). [ISBN](/source/ISBN_(identifier)) [978-1-57506-042-2](https://en.wikipedia.org/wiki/Special:BookSources/978-1-57506-042-2).

1. **[^](#cite_ref-chase_66-0)** Chase, W.T. 1971, "Egyptian blue as a pigment and ceramic material." In: R. Brill (ed.) *Science and Archaeology*. Cambridge, Mass: MIT Press. [ISBN](/source/ISBN_(identifier)) [0-262-02061-0](https://en.wikipedia.org/wiki/Special:BookSources/0-262-02061-0)

1. **[^](#cite_ref-67)** J. Baines, "Color Terminology and Color Classification in Ancient Egyptian Color Terminology and Polychromy", in *The American Anthropologist*, volume 87, 1985, pp. 282–97.

1. **[^](#cite_ref-68)** Caesar, *The Gallic Wars*, V., 14, 2. Cited by Miche Pastourou, p. 178.

1. **[^](#cite_ref-FOOTNOTEPastoureau200026_69-0)** [Pastoureau 2000](#CITEREFPastoureau2000), p. 26.

1. **[^](#cite_ref-70)** L. Brehier, *Les mosaiques a fond d'azur*, in *Etudes Byzantines*, volume III, Paris, 1945. pp. 46ff.

1. **[^](#cite_ref-FOOTNOTEVarichon2005175_71-0)** [Varichon 2005](#CITEREFVarichon2005), p. 175.

1. **[^](#cite_ref-72)** Lours, Mathieu, "Le Vitrail", Editions Jean-Paul Gisserot, Paris (2021)

1. **[^](#cite_ref-FOOTNOTEPastoureau200044–47_73-0)** [Pastoureau 2000](#CITEREFPastoureau2000), pp. 44–47.

1. **[^](#cite_ref-FOOTNOTEPastoureau200051–52_74-0)** [Pastoureau 2000](#CITEREFPastoureau2000), pp. 51–52.

1. **[^](#cite_ref-FOOTNOTEBall2001165_75-0)** [Ball 2001](#CITEREFBall2001), p. 165.

1. **[^](#cite_ref-76)** Travis, Time, "The Victoria and Albert Book of Colour Design" (2020), p. 185

1. **[^](#cite_ref-77)** Travis, Tim, *The Victoria and Albert Museum Book of Colour in Design* (2020), p. 200-201

1. ^ [***a***](#cite_ref-p32_78-0) [***b***](#cite_ref-p32_78-1) [***c***](#cite_ref-p32_78-2) Heller (2010) p.32

1. **[^](#cite_ref-autogenerated1_79-0)** Wassily Kandinsky, M. T. Sadler (Translator) *Concerning the Spiritual in Art*. Dover Publ. (Paperback). 80 pp. [ISBN](/source/ISBN_(identifier)) [0-486-23411-8](https://en.wikipedia.org/wiki/Special:BookSources/0-486-23411-8).

1. **[^](#cite_ref-80)** *"Un certain bleu pénètre votre âme."* Cited in [Riley 1995](#CITEREFRiley1995).

1. **[^](#cite_ref-81)** *Mark Rothko 1903–1970*. Tate Gallery Publishing, 1987.

1. **[^](#cite_ref-82)** Heller (2010) p.31

1. **[^](#cite_ref-83)** J.R. Hill, *The Oxford Illustrated History of the Royal Navy*, Oxford University Press, 1995.

1. **[^](#cite_ref-84)** Walter H. Bradford. ["Wearing Army Blue: a 200-year Tradition"](https://web.archive.org/web/20141119095538/http://www.army.mil/symbols/uniforms/history.html). *army.mil*. Archived from [the original](http://www.army.mil/symbols/uniforms/history.html) on 19 November 2014.

1. **[^](#cite_ref-85)** Jean Tulard, Jean-François Fayard, Alfred Fierro, *Histoire et dictionnaire de la Révolution française*, 1789–1799, Éditions Robert Laffont, collection Bouquins, Paris, 1987. [ISBN](/source/ISBN_(identifier)) [2-7028-2076-X](https://en.wikipedia.org/wiki/Special:BookSources/2-7028-2076-X)

1. **[^](#cite_ref-86)** ["Pink for boys and blue for girls: the colorful history of things designed for kids"](https://today.usc.edu/pink-for-boys-and-blue-for-girls-the-colorful-history-of-things-designed-for-kids/#:~:text=But%20that%20wasn't%20always,wood%20toys%20over%20plastic%20ones?%E2%80%9D). *USC Today*. 22 December 2017. Retrieved 22 October 2024.

1. **[^](#cite_ref-87)** [Numbers](/source/Book_of_Numbers) 15:38.

1. **[^](#cite_ref-88)** [Tekhelet.com](http://www.tekhelet.com) [Archived](https://web.archive.org/web/20080130063924/http://www.tekhelet.com/) 30 January 2008 at the [Wayback Machine](/source/Wayback_Machine), the Ptil Tekhelet Organization

1. **[^](#cite_ref-89)** *[Mishneh Torah](/source/Mishneh_Torah)*, *Tzitzit* 2:1; Commentary on Numbers 15:38.

1. **[^](#cite_ref-90)** *[Numbers Rabbah](/source/Numbers_Rabbah)* 14:3; *[Hullin](/source/Hullin)* 89a.

1. **[^](#cite_ref-91)** [Exodus](/source/Book_of_Exodus) 24:10; [Ezekiel](/source/Ezekiel) 1:26; *[Hullin](/source/Hullin)* 89a.

1. **[^](#cite_ref-92)** [Numbers](/source/Book_of_Numbers) 4:6–12.

1. **[^](#cite_ref-Heller_2009_p._32_93-0)** Heller, "Psychologie de la Colour - Effets et Symboliques", (2009), p. 32

1. **[^](#cite_ref-94)** ["Your question answered"](https://web.archive.org/web/20060904024808/http://campus.udayton.edu/mary/questions/faq/faq12.html). *udayton.edu*. Archived from [the original](http://campus.udayton.edu/mary/questions/faq/faq12.html) on 4 September 2006.

1. **[^](#cite_ref-95)** ["The Spirit of Notre Dame"](http://www.nd.edu/~wcawley/corson/schoolcolors.htm). *Nd.edu*. [Archived](https://web.archive.org/web/20111230134831/http://www.nd.edu/~wcawley/corson/schoolcolors.htm) from the original on 30 December 2011. Retrieved 31 December 2011.

1. **[^](#cite_ref-96)** ["Board Question #31244 | The 100 Hour Board"](http://theboard.byu.edu/questions/31244/). *Theboard.byu.edu*. [Archived](https://web.archive.org/web/20120331124840/http://theboard.byu.edu/questions/31244/) from the original on 31 March 2012. Retrieved 31 December 2011.

1. **[^](#cite_ref-97)** Stevens, Samantha. *The Seven Rays: a Universal Guide to the Archangels*. Toronto: Insomniac Press, 2004. [ISBN](/source/ISBN_(identifier)) [1-894663-49-7](https://en.wikipedia.org/wiki/Special:BookSources/1-894663-49-7). p. 24.

1. **[^](#cite_ref-98)** Sikh Rehat Maryada: [Section Three, Chapter IV, Article V, r.](https://old.sgpc.net/rehat_maryada/section_three_chap_four.htm)

1. **[^](#cite_ref-99)** ["Nishan Sahib Khanda Sikh Symbols Sikh Museum History Heritage Sikhs"](https://www.sikhmuseum.com/nishan/). *www.sikhmuseum.com*.

1. **[^](#cite_ref-100)** ["FIFA World Cup 2010 – Historical Football Kits"](http://historicalkits.co.uk/international/tournaments/fifa_world_cup_2010/fifa-world-cup-2010.html). *Historicalkits.co.uk*. [Archived](https://web.archive.org/web/20120107043904/http://www.historicalkits.co.uk/international/tournaments/fifa_world_cup_2010/fifa-world-cup-2010.html) from the original on 7 January 2012. Retrieved 31 December 2011.

1. **[^](#cite_ref-101)** ["This Is The Reason Why Indian Cricket Team Wears A Blue Jersey During ODIs"](https://www.indiatimes.com/sports/this-is-the-reason-why-indian-cricket-team-wears-a-blue-jersey-during-odis-257727.html). 3 July 2016.

1. **[^](#cite_ref-PsyCoul_102-0)** Heller, "Psychologie de la Couleur" pp. 36-37

1. **[^](#cite_ref-103)** Stone, Terry Lee (2006). [*Color design workbook: a real-world guide to using color in graphic design*](http://archive.org/details/colordesignworkb0000ston). Internet Archive. Gloucester, Mass. : Rockport Publishers. [ISBN](/source/ISBN_(identifier)) [978-1-59253-192-9](https://en.wikipedia.org/wiki/Special:BookSources/978-1-59253-192-9).

1. **[^](#cite_ref-104)** ["Why is the Conservative Party blue?"](https://news.bbc.co.uk/1/hi/magazine/4923050.stm). *BBC News*. 20 April 2006. Retrieved 23 April 2018.

1. **[^](#cite_ref-105)** ["Official Logos"](https://www.conservative.ca/official-logos/). *Conservative Party of Canada*. Retrieved 13 February 2024.

1. **[^](#cite_ref-106)** ["What are the colours of the Australian political parties? - Parliamentary Education Office"](https://peo.gov.au/understand-our-parliament/your-questions-on-notice). *peo.gov.au*. Retrieved 13 February 2024.

1. **[^](#cite_ref-latmpexp16_107-0)** Battaglio, Stephen (3 November 2016). ["When red meant Democratic and blue was Republican. A brief history of TV electoral maps"](https://www.latimes.com/entertainment/tv/la-et-st-electoral-map-20161102-htmlstory.html). *Los Angeles Times*. Retrieved 28 November 2018.

1. **[^](#cite_ref-108)** ["더불어민주당"](https://web.archive.org/web/20230308211933/https://theminjoo.kr/introduce/logo). 8 March 2023. Archived from [the original](https://theminjoo.kr/introduce/logo) on 8 March 2023. Retrieved 13 February 2024.

## Works cited

- Ball, Philip (2001). *Bright Earth, Art, and the Invention of Colour*. London: Penguin Group. p. 507. [ISBN](/source/ISBN_(identifier)) [978-2-7541-0503-3](https://en.wikipedia.org/wiki/Special:BookSources/978-2-7541-0503-3). (page numbers refer to the French translation)

- Bowersox, Gary W.; Chamberlin, Bonita E. (1995). *Gemstones of Afghanistan*. Tucson, AZ: Geoscience Press.

- Heller, Eva (2009). *Psychologie de la couleur: effets et symboliques* (in French). Munich: Pyramyd. [ISBN](/source/ISBN_(identifier)) [978-2-35017-156-2](https://en.wikipedia.org/wiki/Special:BookSources/978-2-35017-156-2).

- Pastoureau, Michel (2000). *Bleu: Histoire d'une couleur* (in French). Paris: Editions du Seuil. [ISBN](/source/ISBN_(identifier)) [978-2-02-086991-1](https://en.wikipedia.org/wiki/Special:BookSources/978-2-02-086991-1).

- Riley, Charles A. II (1995). *Color Codes: Modern Theories of Color in Philosophy, Painting and Architecture, Literature, Music, and Psychology*. Hanover, New Hampshire: University Press of New England.

- Travis, Tim (2020). *The Victoria and Albert Museum Book of Colour in Design*. Thames & Hudson. [ISBN](/source/ISBN_(identifier)) [978-0-500-48027-4](https://en.wikipedia.org/wiki/Special:BookSources/978-0-500-48027-4).

- Varichon, Anne (2005). *Couleurs : pigments et teintures dans les mains des peuples* (in French). Paris: Editions du Seuil. [ISBN](/source/ISBN_(identifier)) [978-2-02-084697-4](https://en.wikipedia.org/wiki/Special:BookSources/978-2-02-084697-4).

- Lours, Mathieu (2020). *Le Vitrai*. Éditions Jean-Paul Gisserot. [ISBN](/source/ISBN_(identifier)) [978-2-755-80845-2](https://en.wikipedia.org/wiki/Special:BookSources/978-2-755-80845-2).

## Further reading

- Balfour-Paul, Jenny (1998). *Indigo*. London: British Museum Press. [ISBN](/source/ISBN_(identifier)) [978-0-7141-1776-8](https://en.wikipedia.org/wiki/Special:BookSources/978-0-7141-1776-8).

- Josserand, M.; Meeussen, E.; Majid, A. (27 September 2021). ["Environment and culture shape both the colour lexicon and the genetics of colour perception"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8476573). *Sci Rep*. **11** (19095). Nature: 19095. [Bibcode](/source/Bibcode_(identifier)):[2021NatSR..1119095J](https://ui.adsabs.harvard.edu/abs/2021NatSR..1119095J). [doi](/source/Doi_(identifier)):[10.1038/s41598-021-98550-3](https://doi.org/10.1038%2Fs41598-021-98550-3). [PMC](/source/PMC_(identifier)) [8476573](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8476573). [PMID](/source/PMID_(identifier)) [34580373](https://pubmed.ncbi.nlm.nih.gov/34580373). [S2CID](/source/S2CID_(identifier)) [238202924](https://api.semanticscholar.org/CorpusID:238202924).

- Macdonald, Fiona (7 April 2018). ["There's Evidence Humans Didn't Actually See Blue Until Modern Times"](https://web.archive.org/web/20220624002709/https://www.sciencealert.com/humans-didn-t-see-the-colour-blue-until-modern-times-evidence-science). *Science Alert*. Archived from [the original](https://www.sciencealert.com/humans-didn-t-see-the-colour-blue-until-modern-times-evidence-science) on 24 June 2022. Retrieved 24 June 2022.

- Mollo, John (1991). *Uniforms of The American Revolution in Color*. Illustrated by [Malcolm McGregor](/source/Malcolm_McGregor). [New York](/source/New_York_City): Stirling Publications. [ISBN](/source/ISBN_(identifier)) [978-0-8069-8240-3](https://en.wikipedia.org/wiki/Special:BookSources/978-0-8069-8240-3).

## External links

- The dictionary definition of [*blue*](https://en.wiktionary.org/wiki/blue) at Wiktionary

- Media related to [blue](https://commons.wikimedia.org/wiki/Category:Blue) at Wikimedia Commons

- ["Friday essay: from the Great Wave to Starry Night, how a blue pigment changed the world", By Hugh Davies, theconversation.com](https://theconversation.com/friday-essay-from-the-great-wave-to-starry-night-how-a-blue-pigment-changed-the-world-81031)

v t e Shades of blue Alice blue Aqua Argentinian blue Azure Baby blue Berkeley blue Bice Bleu de France Blue (Munsell) Blue (NCS) Blue (Pantone) Blue-gray Blue-green Blue-violet Bondi blue Brandeis blue Byzantine blue Cambridge Blue Capri Carolina blue Celestial blue Celtic blue Cerulean Cobalt blue Columbia blue Cornflower blue Cyan Dark blue Deep sky blue Delft blue Dodger blue Duke blue Egyptian blue Electric blue Electric indigo Eton blue French blue Glaucous Haint blue Honolulu blue Horizon blue Indigo Indigo dye International Klein Blue Iris Jordy blue Lapis lazuli Lavender Lavender gray Lavender mist Light blue Light sky blue Majorelle Blue Marian blue Maya blue Medium blue Midnight blue Moroccan blue Navy blue Neon blue Non-photo blue Oxford Blue Palatinate blue Pale azure Penn Blue Periwinkle Persian blue Persian indigo Phthalo blue Picton blue Pigment blue Polynesian blue Powder blue Process blue Prussian blue RAF blue Resolution blue RISD Blue Royal blue Ruddy blue Sapphire Savoy blue Silver Lake blue Sky blue Smalt Space cadet Steel blue Tang blue Teal Turquoise USAF blue Ultramarine United Nations Blue U of T Blue Uranian blue Vista blue Yale Blue YInMn Blue Zaffre Related topics: St. Patrick's blue Shades of cyan

v t e Shades of light blue Alice blue Alice blue (web color) Baby blue Baby blue eyes Beau blue Blue bell Celeste Cool gray Cyan Dark sky blue Lavender (floral) Lavender mist A typical sample is shown for each name; a range of color-variations is commonly associated with each color-name.

v t e Shades of violet African violet Amethyst Blue Bell Blue-violet Blurple Burgundy Byzantium Caput mortuum Celestial Blue Cerise Chinese violet Cotton candy Dark Purple Dark violet Eggplant Electric indigo Electric purple Electric violet Eminence English lavender English violet Fairy Tale Fandango Fandango pink French mauve French violet Fuchsia Grape Heliotrope Indigo Iris Japanese violet Jazzberry Jam Languid lavender Lavender blush Lavender (Crayola (I)) Lavender gray Lavender pink Lavender (floral) Lavender (web) Lilac Magenta Majorelle Blue Mardi Gras Mauve Mauveine Maximum Blue Purple Maximum Red Purple Medium purple Medium slate blue Middle Blue Purple Mimi Pink Mountbatten pink Mulberry Murrey Old lavender Orchid Palatinate Pale lavender Pale purple Periwinkle Periwinkle (Crayola) Persian indigo Persian pink Petunia Pink Lace Pink lavender Plum (web) Pomp and Power Psychedelic purple Puce Purple Purple Heart Purple mountain majesty Purpureus Rebecca purple Red-violet Rose pink Royal purple Russian violet Slate blue Soap Steel pink Tekhelet Thistle Tropical indigo Twilight lavender Tyrian purple Ultra pink Ultra Violet Veronica Vibrant purple Violet Violet-red Violet (web color) Vivid Violet Wisteria A typical sample is shown for each name; a range of color-variations is commonly associated with each color-name.

v t e Shades of lavender #7F7FBF African Violet Amethyst Amethyst (Crayola) Blue Bell Cameo Pink Cool grey Cotton candy English lavender Fairy Tale Glossy grape Heliotrope Heliotrope gray Heliotrope Magenta Lavender (Crayola (I) Languid lavender Lavender blush Lavender burst Lavender (floral) Lavender Glitter Lavender gray Lavender mist Lavender pink Lavender silk Light hot pink Maximum Blue Purple Medium purple Middle Blue Purple Mimi pink Nadeshiko pink Old Heliotrope Old lavender Orchid pink Pale lavender Pale purple Periwinkle Periwinkle (Crayola) Pink lavender Pink lace Pink luster Plum (web) Purple mountain majesty Purple Mountains' Majesty Rhythm Shampoo Soap Tropical indigo Twilight lavender Violet (web color) Wisteria A typical sample is shown for each name; a range of color-variations is commonly associated with each color-name.

v t e Shades of cyan Alice blue Aqua Aquamarine Azure Azure (web) Blue-green Capri Caribbean Current Celeste Cerulean Cyan (sRGB) Dark cyan Electric blue Fluorescent cyan Haint blue Jungle green Keppel Ice blue Light blue Light cyan Light sea green Midnight Green Mint green Mint Moonstone Myrtle Green Olo Pacific cyan Persian green Process Cyan Riptide Robin egg blue Sea green Skobeloff Sky blue (Crayola) Spring green Teal Tiffany Blue Turquoise Verdigris Vivid sky blue Zomp A typical sample is shown for each name; a range of color-variations is commonly associated with each color-name.

v t e Shades of indigo #6A35CE Blue Bell Blue-Violet Blue-Violet (Crayola) Celestial blue Denim Electric Indigo Electric Ultramarine Imperial blue Indigo Indigo (color wheel) Indigo (Crayola) Indigo dye Iridescent Indigo Iron Indigo Lavender mist Maximum blue purple Middle Blue Purple Midnight blue Moonlit Pond Ocean Blue Pearl Periwinkle Periwinkle (Crayola) Plump Purple Purple Heart Purple mountain majesty Royal purple (Crayola) Tropical indigo Ultramarine Ultramarine Blue Violet-Blue (Crayola) Web color indigo Web safe indigo A typical sample is shown for each name; a range of color-variations is commonly associated with each color-name.

Articles related to Blue v t e Colour topics Colour science Colour physics Electromagnetic spectrum Light Rainbow Visible Spectral colours Chromophore Structural colouration Animal colouration Colour of chemicals Water Spectral power distribution Colorimetry Colour perception Chromesthesia Sonochromatism Colour blindness Achromatopsia Dichromacy Colour calibration Colour constancy Colour task Colour code Colour temperature Colour vision test Evolution of colour vision Impossible colours Metamerism Opponent process Afterimage Unique hues Tetrachromacy The dress Colour psychology Colour symbolism Colour preferences Lüscher colour test Kruithof curve Political colour National colours Chromophobia Chromotherapy Colour reproduction Colour photography Colour balance Colour cast Digital image processing Colour management Colour printing Multi-primary colour display Quattron Colour model additive RGB subtractive CMYK Colour space Image colour transfer Colour philosophy Colour scheme Colour tool Monochromatic colours Black and white Grisaille Complementary colours Analogous colours Achromatic colours (Neutral) Polychromatic colours Light-on-dark Web colours Tinctures in heraldry Colour theory Colour mixing Primary colour Secondary colour Chromaticity Colour solid Colour wheel Colour triangle Colour analysis (fashion) Colour realism (art style) On Vision and Colours (Schopenhauer) Theory of Colours (Goethe) Colour terms Basic English terms Red Orange Yellow Green Blue Purple Pink Brown White Grey Black Cultural differences Linguistic relativity and the colour naming debate Blue–green distinction in language Colour history Black-and-white dualism Blue in culture Colour in Chinese culture Traditional colours of Japan Human skin colour Colour dimensions Hue Dichromatism Colourfulness Pastel colours Luminance Lightness Darkness Brightness Iridescence Fluorescence Grayscale Tint, shade and tone Colour organisations Pantone Color Marketing Group Color Association of the United States International Colour Authority International Commission on Illumination (CIE) International Colour Consortium International Colour Association Names Lists Alphabetical List of colours: A–F G–M N–Z Full list List of colours by shade List of colour palettes List of colour spaces List of Crayola crayon colours history Colour chart List of RAL colours List of web colours Shades of: Red Orange Yellow Green Cyan Blue Violet Purple Magenta Pink Brown White Gray Black Related Vision Contrast Qualia Lighting Category Index v t e Electromagnetic spectrum Gamma rays X-rays Ultraviolet Visible Infrared Microwave Radio ← higher frequencies, higher energy, shorter wavelengths longer wavelengths, lower frequencies, lower energy → Gamma rays Very-high-energy Ultra-high-energy X-rays Soft X-ray Hard X-ray High-energy X-rays Ultraviolet Extreme ultraviolet Vacuum ultraviolet Lyman-alpha FUV MUV NUV UVC UVB UVA Visible (optical) Violet Blue Cyan Green Yellow Orange Red Infrared NIR (Bands: J, K, H) SWIR MWIR (Bands: L, M, N) LWIR FIR Microwaves W band V band Q band Ka band K band Ku band X band C band S band L band Radio THF EHF SHF UHF VHF HF MF LF VLF ULF SLF ELF Wavelength types Microwave Shortwave Medium wave Longwave v t e Web colours White Gray/Grey Red Yellow Lime Aqua/Cyan Blue Fuchsia/Magenta Silver Black Maroon Olive Green Teal Navy blue Purple Category

Authority control databases International GND FAST National United States France BnF data Czech Republic Israel Other Yale LUX

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Adapted from the Wikipedia article [Blue](https://en.wikipedia.org/wiki/Blue) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Blue?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.