Editing Orange (colour) (section)

==Science==
===Optics===
[[File:Kleurenovergang van rood naar geel.png|thumb|centre|300px|In traditional [[colour theory]], orange is a range of colours between red and yellow]]
In [[optics]], orange is the colour seen by the eye when looking at light with a wavelength between approximately 585–620{{nbsp}}[[nanometre|nm]]. It has a [[hue]] of 30° in [[HSL and HSV|HSV colour space]]. Isaac Newton's ''[[Opticks]]'' distinguished between pure orange light and mixtures of red and yellow light by noting that mixtures could be separated using a prism.<ref>Isaac Newton, [https://archive.org/details/opticksoratreat00newtgoog/page/n134/mode/2up Opticks: or, A Treatise of the Reflexions, Refractions, Inflexions and Colours of Light], Book I, Prop IV, Theor III</ref>

In the traditional colour wheel used by painters, orange is the range of colours between red and yellow, and painters can obtain orange simply by mixing red and yellow in various proportions; however these colours are never as vivid as a pure orange pigment. In the [[RGB colour model]] (the system used to display colours on a television or computer screen), orange is generated by combining high intensity red light with a lower intensity green light, with the blue light turned off entirely. Orange is a [[tertiary colour]] which is numerically halfway between [[gamma correction|gamma-compressed]] red and yellow, as can be seen in the [[:File:RBG color wheel.svg|RGB colour wheel]].

Regarding painting, blue is the complementary colour to orange. As many painters of the 19th century discovered, blue and orange reinforce each other. The painter Vincent van Gogh wrote to his brother Theo that in his paintings, he was trying to reveal "the oppositions of blue with orange, of red with green, of yellow with violet{{nbsp}}... trying to make the colours intense and not a harmony of grey".<ref>''Correspondance'' of Vincent van Gogh, No. 459A, cited in John Gage, ''Couleur et Culture: Usages et significations de la couleur de l'Antiquité à l'abstraction''.</ref> In another letter he wrote simply, "There is no orange without blue."<ref>Eva Heller, ''Psychologie de la couleur: effets et symboliques'', p. 152.</ref> Van Gogh, [[Pierre-Auguste Renoir]] and many other [[Impressionist]] and [[Post-Impressionist]] painters frequently placed orange against azure or cobalt blue, to make both colours appear brighter.

The actual complement of orange is [[azure (color)|azure]] – a colour that is one quarter of the way between blue and green on the colour spectrum. The actual complementary colour of true blue is yellow. Orange pigments are largely in the [[ochre]] or [[Cadmium pigments|cadmium]] families, and absorb mostly greenish-blue light.

===Pigments and dyes===
<gallery mode="packed" heights="150px">
File:Orpiment mineral.jpg|A sample of [[orpiment]] from an arsenic mine in [[southern Russia]]. Orpiment has been used to make orange pigment since ancient times in ancient Egypt, Europe and China. Romans used the mineral for trade.
File:Realgar09.jpg|[[Realgar]], an arsenic sulfide mineral 1.5-2.5 Mohs hardness, is highly toxic. It was used since ancient times until the 19th century to make red-orange pigment, as a poison, and a medicine.
File:Crocoite from the Dundas extended mine, Dundas, Tasmania, Australia.jpg|A sample of [[crocoite]] crystals from [[Dundas, Tasmania|Dundas]] extended mine in [[Tasmania]]. Discovered in 1797 by the French chemist [[Louis Vauquelin]], it was used to make the first synthetic orange pigment, [[chrome orange]], used by [[Pierre-Auguste Renoir]] and other painters.
File:Safran-Weinviertel Niederreiter 2 Gramm 8285.jpg|[[Saffron]], made from the hand-picked [[stigma (botany)|stigma]]s of the ''[[Crocus sativus]]'' flower, is used both as a dye and as a spice.
File:Curcuma longa (Haldi) W IMG 2440.jpg|The [[Curcuma longa]] plant is used to make [[turmeric]], a common and less expensive substitute for saffron as a dye and colour.
File:Curcuma longa roots.jpg|[[Turmeric|Turmeric powder]], first used as a dye, and later as a medicine and spice in [[Indian cuisine]].
</gallery>

Other orange pigments include:
*[[Minium (pigment)|Minium]] and [[massicot]] are bright yellow and orange pigments made since ancient times by heating lead oxide and its variants. Minium was used in the [[Byzantine Empire]] for making the red-orange colour on illuminated manuscripts, while massicot was used by ancient Egyptian scribes and in the Middle Ages. Both substances are toxic, and were replaced in the beginning of the 20th century by chrome orange and cadmium orange.<ref>Isabelle Roelofs and Fabien Petillion, ''La couleur expliquée aux artistes'', pp. 46–47.</ref>
*[[Cadmium orange]] is a synthetic pigment made from [[cadmium sulfide|cadmium sulphide]]. It is a by-product of mining for [[zinc]], but also occurs rarely in nature in the mineral [[greenockite]]. It is usually made by replacing some of the [[sulfur|sulphur]] with [[selenium]], which results in an expensive but deep and lasting colour. [[Selenium]] was discovered in 1817, but the pigment was not made commercially until 1910.<ref>Isabelle Roelofs and Fabien Petillion, ''La couleur expliquée aux artistes'', p. 121.</ref>
*[[Quinacridone]] orange is a synthetic organic pigment first identified in 1896 and manufactured in 1935. It makes a vivid and solid orange.
*[[Diketopyrrolopyrrole dye|Diketopyrrolopyrrole orange]] or DPP orange is a synthetic organic pigment first commercialised in 1986. It is sold under various commercial names, such as translucent orange. It makes an extremely bright and lasting orange, and is widely used to colour plastics and fibres, as well as in paints.<ref>Isabelle Roelofs and Fabien Petillion, ''La couleur expliquée aux artistes'', pp. 66–67</ref>

===Orange natural objects===
The orange colour of [[carrot]]s, [[pumpkin]]s, [[sweet potato]]es, [[Orange (fruit)|oranges]], and many other fruits and vegetables comes from [[carotene]]s, a type of [[photosynthetic pigment]]. These pigments convert the light energy that the plants absorb from the sun into chemical energy for the plants' growth. The carotenes themselves take their name from the carrot.<ref>{{cite web|url=https://www.britannica.com/EBchecked/topic/96623/carotenoid|title=carotenoid|website=Encyclopædia Britannica|access-date=25 September 2014}}</ref> [[Autumn leaf color|Autumn leaves]] also get their orange colour from carotenes. When the weather turns cold and production of green [[chlorophyll]] stops, the orange colour remains.

Before the 18th century, carrots from Asia were usually purple, while those in Europe were either white or red. Dutch farmers bred a variety that was orange; according to some sources, as a tribute to the [[stadtholder]] of [[Holland]] and [[Zeeland]], [[William the Silent|William of Orange]].<ref>{{cite news|url=https://www.washingtonpost.com/blogs/wonkblog/post/carrots-are-orange-for-an-entirely-political-reason/2011/09/09/gIQAfayiFK_blog.html|title=Are carrots orange for political reasons?|newspaper=Washington Post|access-date=25 September 2014}}</ref> The long orange Dutch carrot, first described in 1721, is the ancestor of the orange horn carrot, one of the most common types found in supermarkets today. It takes its name from the town of [[Hoorn]], in the Netherlands.

<gallery mode="packed" heights="150">
File:CarrotDiversityLg.jpg|Carrots, pumpkins and other vegetables get their orange colour from [[carotene]]s, a variety of [[photosynthetic pigment]], which takes its own name from the carrot.
File:Japanese maple.jpg|A [[Japanese maple]] tree in autumn. [[Autumn leaf color|Autumn leaves]] also get their orange colour from carotenes.
File:Traugers-farm-bucks-county-large.jpg|[[Pumpkins]]
File:CarrotRoots.jpg|[[Carrot]]s
File:5aday sweet potato.jpg|[[Sweet potato]]es
File:Orange-Fruit-Pieces.jpg|[[Orange (fruit)|Oranges]]
File:Mandarin Oranges (Citrus Reticulata).jpg|[[Mandarin orange|Mandarins]]
</gallery>

===Flowers===
Orange is traditionally associated with the [[autumn]] season, with the harvest and autumn leaves. The flowers, like orange fruits and vegetables and autumn leaves, get their colour from the photosynthetic pigments called [[carotene]]s.
<gallery mode="packed" heights="150">
File:California Poppies1.jpg|A field of [[Eschscholzia californica|California poppies]]
File:Calendula officinalis 0.0 R.jpg|The [[Pot marigold|marigold]] flower, or ''[[Calendula]]''
File:- Flower 19 -.jpg|Poppy flower
File:Daylily (Hemerocallis fulva) v2.jpg|Daylily (''Hemerocallis fulva'')
File:Begonia 'On Top Sunset Shades' 01.JPG|Begonia cultivar
File:Sylvia Ball-Dahlie.JPG|The [[dahlia]]
File:Orange Rose1.jpg|An orange [[rose]]
File:Orange hibiscus.jpg|alt=Orange hibiscus|Orange [[hibiscus]]
File:Butterfly Weed Asclepias tuberosa Buds.jpg|buds of the butterfly weed, or ''[[Asclepias tuberosa]]''
File:Hieracium aurantiacum LC0106.jpg|''[[Hieracium aurantiacum]]'', or orange hawkweed
File:Heliconia psittacorum 01.JPG|''[[Heliconia psittacorum]]'', or parrot's flower, is a perennial herb native to the Caribbean and northern South America.
File:Fritillaria imperialis 01.JPG|''[[Fritillaria imperialis]]''
File:Yellow French Marigold Flower.jpg|''[[Tagetes erecta]]'' (marigold)
File:Vanda garayi.png|''[[Vanda garayi]]''
</gallery>

===Animals===
<gallery mode="packed" heights="150px">
File:Canario paxaro.jpg|[[Canary bird]]
File:Panthera tigris tigris.jpg|A [[Bengal tiger]] (''Panthera tigris tigris'')
File:Red Squirrel - Lazienki.JPG|A [[red squirrel]] is actually orange.
File:Vulpes vulpes laying in snow.jpg|A [[red fox]], or ''Vulpes vulpes'', in the snow.
File:Iguana iguana (orange male).jpg|An [[iguana]]
File:A couple of Tadorna ferruginea.2.jpg|The ''[[Tadorna ferruginea]]'', or ruddy shelduck, lives in Southeast Europe, Central Asia and Southeast Asia, and migrates in the winter to India.
File:Flamingo National Zoo.jpg|An orange [[flamingo]] in the [[National Zoological Park (United States)|National Zoo]] in Washington, D.C.
File:Altamira Oriole icterus gularis, Bentsen State Park TX.jpg|An [[Altamira oriole]] in Bentsen State Park, Texas.
File:Flame angelfish (Centropyge loricula).jpg|A [[flame angelfish]], or ''Centropyge loricula''
File:Auftauchender Koi 2011.JPG|A [[koi]], a domesticated [[carp]] bred in Japan for its ornamental value in gardens and ponds
File:Arion rufus (Dourbes).jpg|An ''[[Arion rufus]]'', or European red slug, lives in northern Europe, especially Denmark, and can be eighteen centimetres long.
</gallery>

===Foods===
Orange is a very common colour of fruits, vegetables, spices, and other foods in many different cultures. As a result, orange is the colour most often associated in western culture with taste and aroma.<ref>Eva Heller, ''Psychologie de la couleur: effets et symboliques'', p. 152</ref> Orange foods include peaches, [[apricot]]s, [[mangoes]], [[carrot]]s, [[shrimp]], [[salmon roe]], and many other foods. Orange colour is provided by [[spice]]s such as [[paprika]], [[saffron]] and [[curry powder]]. In the United States, with [[Halloween]] on 31 October, and in North America with [[Thanksgiving]] in October (Canada) and November (US) orange is associated with the harvest colour, and also is the colour of the carved pumpkins, or jack-o-lanterns, used to celebrate the holiday.

<gallery mode="packed" heights="120px">
File:Pumpkin-Pie-Whole-Slice.jpg|Orange-coloured [[pumpkin pie]] is the traditional dessert at a US [[Thanksgiving]] dinner.
File:Melon au vin muscat.jpg|A [[melon]] with [[Muscat (grape)|Muscat]] wine (France).
File:Mashedpumpkin.jpg|A bowl of [[mashed pumpkin]]
File:TzimmesS.jpg|Carrot [[tzimmes]]
File:Apricots real.jpg|[[Apricot]]s
File:Oronges.jpg|''[[Amanita caesarea]]'' known in English as Caesar's mushroom
File:Salmon Fish.JPG|[[Salmon]] steaks
File:Mangga gedong mango juice.JPG|[[Mango]] juice
File:Homemade marmalade, England.jpg|Homemade English [[marmalade]]
File:Khrenovina-sauce.jpg|[[Khrenovina sauce]], a traditional [[Siberia]]n sauce made of tomatoes, garlic and horseradish.
File:Paella valenciana.gif|[[Paella]] from [[Valencia]], Spain
File:Indian cuisine-Panipuri-05.jpg|[[Panipuri]], a popular street snack in the Indian subcontinent
File:Curry Ist.jpg|[[Curry powder]] from the Indian subcontinent
File:Spanishsmokedpaprika.jpg|[[Paprika]] from Spain
</gallery>

===Food colourings===
[[File:Doritos.jpg|thumb|upright|Nacho cheese [[Doritos]], like many popular snack foods, contain [[Yellow 6]], [[Yellow 5]] and [[Red 40]] synthetic food colour.]]
[[File:Single wrapped slice of processed cheese.jpg|thumb|upright|Wrapped slices of [[American cheese]] are now often coloured with [[annatto]], a natural food colour made from the seeds of the [[achiote]] tree.]]

People associate certain colours with certain [[Flavor (taste)|flavours]], and the colour of food can influence the perceived flavour in anything from [[confectionery|candy]] to [[wine]].<ref>{{cite journal |author=Jeannine Delwiche |title=The impact of perceptual interactions on perceived flavor |journal=Food Quality and Preference |year=2003 |volume=14 |issue=2 |pages=137–146 |doi=10.1016/S0950-3293(03)00041-7 |url=http://www-fst.ag.ohio-state.edu/Pubs/2004/delwiche-fqap1.pdf |url-status=dead |archive-url=https://web.archive.org/web/20130228041745/http://www-fst.ag.ohio-state.edu/Pubs/2004/delwiche-fqap1.pdf |archive-date=2013-02-28 |citeseerx=10.1.1.103.7087 }}</ref> Since orange is popularly associated with good flavour, many companies add orange [[food colouring]] to improve the appearance of their packaged foods. Orange pigments and dyes, synthetic or natural, are added to many orange sodas and juices, cheeses (particularly [[cheddar cheese]], [[Gloucester cheese]], and [[American cheese]]); snack foods, butter and margarine; breakfast cereals, ice cream, [[yoghurt]], jam and candy. It is also often added to children's medicine, and to [[chicken feed]] to make the [[egg yolk]]s more orange.

The United States Government and the [[European Union]] certify a small number of synthetic chemical colourings to be used in food. These are usually [[aromatic hydrocarbon]]s, or [[azo dyes]], made from petroleum. The most common ones are:
*[[Allura red AC]], also known as Red 40 and [[E number|E129]].
*[[Sunset Yellow FCF]], also known as Yellow 6 and [[E number|E110]].
*[[Tartrazine]], also known as Yellow 5 and [[E number|E102]]. A dye used in soft drinks such as [[Mountain Dew]], [[Kool-Aid]], chewing gum, popcorn, breakfast cereals, cosmetics, shampoos, eyeshadow, blush, and lipstick.
*[[Orange B]] is approved by the US [[Food and Drug Administration]], but only for hot dog and sausage casings.
*[[Citrus Red 2]] is certified only to colour orange peels.
Because many consumers are worried about possible health consequences of synthetic dyes, some companies are beginning to use natural food colours. Since these food colours are natural, they do not require any certification from the Food and Drug Administration. The most popular natural food colours are:
*[[Annatto]], made from the seeds of the [[achiote]] tree. Annatto contains [[carotenoid]]s, the same ingredient that gives carrots and other vegetables their orange colour. Annatto has been used to dye certain cheeses in Britain, particularly [[Gloucester cheese]], since the 16th century. It is now commonly used to colour American cheese, snack foods, breakfast cereal, butter, and margarine. It is used as a body paint by native populations in Central and South America. In India, women often put it, under the name ''[[sindoor|sindūra]]'', on their hairline to indicate that they are married.
*[[Turmeric]] is a common spice in the Indian subcontinent, Persia and the Mideast. It contains the pigments called [[curcuminoid]]s, widely used as a dye for the robes of Buddhist monks. It is also often used in curry powders and to give flavour to [[mustard (condiment)|mustard]]. It is now being used more frequently in Europe and the US to give an orange colour to canned beverages, ice cream, yogurt, popcorn and breakfast cereal. The food colour is usually listed as E100.
*[[Paprika oleoresin]] contains natural carotenoids, and is made from [[chili pepper]]s. It is used to colour cheese, orange juice, spice mixtures and packaged sauces. It is also fed to chickens to make their [[egg yolk]]s more orange.