Editing Pigment

{{Short description|Powder used to add or alter colour}}
{{redirect|Pigments|album|Pigments (album)}}
{{Use dmy dates|date=February 2018}}
[[File:Indian pigments.jpg|thumb|upright=1.35|Pigments for sale at a market stall in [[Goa]], [[India]]]]
A '''pigment''' is a [[powder]] used to add or alter [[color]] or change visual appearance. Pigments are completely or nearly [[solubility|insoluble]] and [[reactivity (chemistry)|chemically unreactive]] in water or another medium; in contrast, [[dye]]s are colored substances which are soluble or go into solution at some stage in their use.<ref>{{cite book |last1=Gürses |first1=A. |last2=Açıkyıldız |first2=M. |last3=Güneş |first3=K. |last4=Gürses |first4=M.S. |year=2016 |chapter=Dyes and Pigments: Their Structure and Properties |title=Dyes and Pigments |series=SpringerBriefs in Molecular Science |publisher=Springer |doi=10.1007/978-3-319-33892-7_2 |pages=13–29 |isbn=978-3-319-33890-3 |quote=Dyes are colored substances which are soluble or go into solution during the application process and impart color by selective absorption of light. Pigments are colored, colorless, or fluorescent particulate organic or inorganic finely divided solids which are usually insoluble in, and essentially chemically unaffected by, the vehicle or medium in which they are incorporated.}}</ref><ref>{{cite encyclopedia |encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry |doi=10.1002/14356007.a20_243.pub2 |title=Pigments, Inorganic |last1=Völz |first1=Hans G. |last2=Kischkewitz |first2=Jürgen |last3=Woditsch |first3=Peter |last4=Westerhaus |first4=Axel |last5=Griebler |first5=Wolf-Dieter |last6=De Liedekerke |first6=Marcel |last7=Buxbaum |first7=Gunter |last8=Printzen |first8=Helmut |last9=Mansmann |first9=Manfred |last10=Räde |first10=Dieter |last11=Trenczek |first11=Gerhard |last12=Wilhelm |first12=Volker |last13=Schwarz |first13=Stefanie |last14=Wienand |first14=Henning |last15=Adel |first15=Jörg |last16=Adrian |first16=Gerhard |last17=Brandt |first17=Karl |last18=Cork |first18=William B. |last19=Winkeler |first19=Heinrich |last20=Mayer |first20=Wielfried |last21=Schneider |first21=Klaus |last22=Leitner |first22=Lutz |last23=Kathrein |first23=Hendrik |last24=Schwab |first24=Ekkehard |last25=Jakusch |first25=Helmut |last26=Ohlinger |first26=Manfred |last27=Veitch |first27=Ronald |last28=Etzrodt |first28=Günter |last29=Pfaff |first29=Gerhard |last30=Franz |first30=Klaus-Dieter |date=2006 |display-authors=1 |isbn=3527306730}}</ref> Dyes are often [[organic compound]]s whereas pigments are often [[inorganic compound|inorganic]]. Pigments of prehistoric and historic value include [[ochre]], [[charcoal]], and [[lapis lazuli]].
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For industrial applications, as well as in the arts, permanence and stability are desirable properties.  Pigments that are not permanent are called [[fugitive pigments|fugitive]]. Fugitive pigments fade over time, or with exposure to light, while some eventually blacken. Pigments are used for coloring [[paint]], [[ink]], [[plastic]], [[textile|fabric]], [[cosmetics]], [[food]], and other materials. Most pigments used in [[manufacturing]] and the [[visual arts]] are dry [[colorant]]s, usually ground into a fine [[Powder (substance)|powder]].  For use in paint, this powder is added to a [[paint#Binder (or film former)|binder]] (or vehicle), a relatively neutral or colorless material that [[suspension (chemistry)|suspends]] the pigment and gives the paint its [[adhesion]].  A distinction is usually made between a pigment, which is [[insoluble]] in its vehicle (resulting in a suspension), and a [[dye]], which either is itself a [[liquid]] or is soluble in its vehicle (resulting in a solution). A colorant can act as either a pigment or a dye depending on the vehicle involved. In some cases, a pigment can be manufactured from a dye by [[precipitation (chemistry)|precipitating]] a soluble dye with a metallic salt. The resulting pigment is called a [[lake pigment]]. The term [[biological pigment]] is used for all colored substances independent of their solubility.<ref>{{cite news |url=https://www.latimes.com/archives/la-xpm-2011-oct-14-la-sci-ancient-paint-20111014-story.html |title=Artifacts indicate a 100,000-year-old art studio |first=Amina |last=Khan |date=14 October 2011 |work=[[Los Angeles Times]] |url-status=live |archive-url=https://web.archive.org/web/20151119233414/http://articles.latimes.com/2011/oct/14/science/la-sci-ancient-paint-20111014 |archive-date=19 November 2015}}</ref>-->

==Economic impact==
In 2006, around 7.4&nbsp;million tons of [[inorganic chemistry|inorganic]], [[organic chemistry|organic]], and special pigments were marketed worldwide.<ref>{{Cite journal |last1=Sahoo |first1=Annapurna |last2=Panigrahi |first2=G. K. |date=1 September 2016 |title=A review on Natural Dye: Gift from bacteria |url=https://www.ijbio.com/articles/a-review-on-natural-dye-gift-from-bacteria.pdf |journal=International Journal of Bioassays|volume=5 |issue=9 |pages=4909}}</ref> According to an April 2018 report by ''[[Bloomberg Businessweek]]'', the estimated value of the pigment industry globally is $30 billion. The value of [[titanium dioxide]] &ndash; used to enhance the white brightness of many products &ndash; was placed at $13.2 billion per year, while the color [[Ferrari]] red is valued at $300 million each year.<ref>{{cite news |last=Schonbrun |first=Zach |url=https://www.bloomberg.com/features/2018-quest-for-billion-dollar-red/ |title=The Quest for the Next Billion-Dollar Color |work=[[Bloomberg Businessweek]] |date=2018-04-18 |access-date=2018-05-02}}</ref>

==Physical principles==
{{Main|Spectroscopy}}
[[File:Simple reflectance.svg|thumb|A wide variety of wavelengths (colors) encounter a pigment. This pigment absorbs red and green light, but reflects blue—giving the substance a blue-colored appearance.]]
Like all materials, the color of pigments arises because they absorb only certain wavelengths of [[light|visible light]]. The bonding properties of the material determine the wavelength and efficiency of light absorption.<ref>Thomas B. Brill, ''Light: Its Interaction with Art and Antiquities'', Springer 1980, p. 204</ref> Light of other wavelengths are reflected or scattered. The reflected light spectrum defines the [[color]] that we observe.

The appearance of pigments is sensitive to the source light. Sunlight has a high [[color temperature]] and a fairly uniform spectrum. Sunlight is considered a standard for white light. Artificial light sources are less uniform.

Color spaces used to represent colors numerically must specify their light source. [[Lab color space|Lab color]] measurements, unless otherwise noted, assume that the measurement was recorded under a D65 light source, or "Daylight 6500 K", which is roughly the [[color temperature]] of sunlight.
[[File:Complex reflectance.svg|thumb|400px|Sunlight encounters Rosco R80 "Primary Blue" pigment. The product of the source spectrum and the reflectance spectrum of the pigment results in the final spectrum, and the appearance of blue.]]

Other properties of a color, such as its saturation or lightness, may be determined by the other substances that accompany pigments. Binders and fillers can affect the color.

==History==
Minerals have been used as colorants since prehistoric times.<ref name="StClair">{{cite book |title=The Secret Lives of Colour |last=St. Clair |first=Kassia |publisher=John Murray |year=2016 |isbn=9781473630819 |location=London |pages=21, 237 |oclc=936144129}}</ref> Early humans used [[paint]] for aesthetic purposes such as body decoration. Pigments and paint grinding equipment believed to be between 350,000 and 400,000 years old have been reported in a [[cave]] at Twin Rivers, near [[Lusaka]], [[Zambia]]. [[Ochre]], iron oxide, was the first color of paint.<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/sci/tech/733747.stm |title=Earliest evidence of art found |work=BBC News |date=2 May 2000 |access-date=1 May 2016 |url-status=live |archive-url=https://web.archive.org/web/20160603214144/http://news.bbc.co.uk/2/hi/sci/tech/733747.stm |archive-date=3 June 2016}}</ref> A favored blue pigment was derived from [[lapis lazuli]]. Pigments based on minerals and clays often bear the name of the city or region where they were originally mined. [[Sienna|Raw sienna]] and [[burnt sienna]] came from [[Siena]], [[Italy]], while [[raw umber]] and [[burnt umber]] came from [[Umbria]]. These pigments were among the easiest to synthesize, and chemists created modern colors based on the originals. These were more consistent than colors mined from the original ore bodies, but the place names remained. Also found in many [[Paleolithic]] and [[Neolithic]] [[cave painting]]s are Red Ochre, anhydrous Fe<sub>2</sub>O<sub>3</sub>, and the hydrated Yellow Ochre (Fe<sub>2</sub>O<sub>3</sub><sup>.</sup>H<sub>2</sub>O).<ref name="webexhibits1">{{cite web |url=http://webexhibits.org/pigments/ |title=Pigments Through the Ages |access-date=18 October 2007 |work=WebExhibits |url-status=live |archive-url=https://web.archive.org/web/20071011071107/http://webexhibits.org/pigments/ |archive-date=11 October 2007}}</ref> Charcoal—or carbon black—has also been used as a black pigment since prehistoric times.<ref name="webexhibits1"/>

The first known synthetic pigment was [[Egyptian blue]], which is first attested on an alabaster bowl in Egypt dated to [[Naqada III]] (''circa'' 3250 BC).<ref>Lorelei H. Corcoran, "The Color Blue as an 'Animator' in Ancient Egyptian Art", in Rachael B.Goldman, (ed.), ''Essays in Global Color History: Interpreting the Ancient Spectrum'' (New Jersey: Gorgias Press, 2016), pp. 59–82.</ref><ref>{{cite book |last=Rossotti |first=Hazel |title=Colour: Why the World Isn't Grey |year=1983 |publisher=Princeton University Press |location=Princeton, NJ |isbn=0-691-02386-7 |url=https://archive.org/details/colour00ross}}</ref> Egyptian blue (blue frit), calcium copper silicate CaCuSi<sub>4</sub>O<sub>10</sub>, made by heating a mixture of [[quartz]] sand, [[limestone|lime]], a [[ceramic flux|flux]] and a [[copper]] source, such as [[malachite]].<ref>{{cite journal |last=Berke |first=Heinz |title=The invention of blue and purple pigments in ancient times |journal=Chemical Society Reviews |volume=36 |pages=15–30 |date=2007 |issue=1 |doi=10.1039/b606268g |pmid=17173142 |url=https://pubs.rsc.org/en/content/articlelanding/2007/cs/b606268g}}</ref> Already invented in the [[Predynastic Period of Egypt]], its use became widespread by the [[4th Dynasty]].<ref>{{cite journal |last1=Hatton |first1=G.D. |last2=Shortland |first2=A.J. |last3=Tite |first3=M.S. |title=The production technology of Egyptian blue and green frits from second millenium BC Egypt and Mesopotamia |journal=Journal of Archaeological Science |volume=35 |pages=1591–1604 |date=2008 |issue=6 |doi=10.1016/j.jas.2007.11.008 |bibcode=2008JArSc..35.1591H |url=https://www.sciencedirect.com/science/article/abs/pii/S0305440307002166}}</ref> It was the blue pigment par excellence of [[Roman antiquity]]; its art technological traces vanished in the course of the [[Middle Ages]] until its rediscovery in the context of the [[Egyptian campaign]] and the excavations in [[Pompeii]] and [[Herculaneum]].<ref name="NaturePortfolio">{{cite journal |last1=Dariz |first1=Petra |last2=Schmid |first2=Thomas |title=Trace compounds in Early Medieval Egyptian blue carry information on provenance, manufacture, application, and ageing |journal=Scientific Reports |volume=11 |number=11296 |date=2021 |page=11296 |doi=10.1038/s41598-021-90759-6 |pmid=34050218 |pmc=8163881 |bibcode=2021NatSR..1111296D}}</ref> Later premodern synthetic pigments include [[white lead]] (basic lead carbonate, (PbCO<sub>3</sub>)<sub>2</sub>Pb(OH)<sub>2</sub>),<ref>[http://colourlex.com/project/lead-white/ Lead white] {{webarchive|url=https://web.archive.org/web/20151225004451/http://colourlex.com/project/lead-white/ |date=25 December 2015}} at ColourLex</ref> [[vermilion]], [[verdigris]], and [[lead-tin yellow]]. Vermilion, a [[mercury (element)|mercury]] [[sulfide]], was originally made by grinding a powder of natural [[cinnabar]]. From the 17th century on, it was also synthesized from the elements.<ref>{{cite book |title=The Secret Lives of Colour |last=St. Clair |first=Kassia |publisher=John Murray |year=2016 |isbn=9781473630819 |location=London |pages=146 |oclc=936144129}}</ref> It was favored by old masters such as [[Titian]]. [[Indian yellow]] was once produced by collecting the urine of cattle that had been fed only [[mango]] leaves.<ref name="History of Indian Yellow">{{cite web |url=http://www.webexhibits.org/pigments/indiv/history/indianyellow.html |title=History of Indian yellow |work=Pigments Through the Ages |access-date=13 February 2015 |url-status=live |archive-url=https://web.archive.org/web/20141221234605/http://www.webexhibits.org/pigments/indiv/history/indianyellow.html |archive-date=21 December 2014}}</ref> Dutch and Flemish painters of the 17th and 18th centuries favored it for its [[luminescent]] qualities, and often used it to represent [[sunlight]].{{Citation needed|date=August 2011}} Since mango leaves are nutritionally inadequate for cattle, the practice of harvesting Indian yellow was eventually declared to be inhumane.<ref name="History of Indian Yellow"/> Modern hues of Indian yellow are made from synthetic pigments. Vermillion has been partially replaced in by cadmium reds.

Because of the cost of [[lapis lazuli]], substitutes were often used. [[Prussian blue]], the oldest modern synthetic pigment, was discovered by accident in 1704.<ref>[https://colourlex.com/project/prussian-blue/ Prussian blue] at ColourLex</ref> By the early 19th century, synthetic and metallic blue pigments included [[ultramarine|French ultramarine]], a synthetic form of [[lapis lazuli]]. Ultramarine was manufactured by treating [[aluminium silicate]] with [[sulfur]]. Various forms of [[cobalt blue]] and [[Cerulean blue]] were also introduced. In the early 20th century, [[Phthalocyanine Blue BN|Phthalo Blue]], a synthetic metallo-organic pigment was prepared. At the same time, [[Royal Blue]], another name once given to tints produced from lapis lazuli, has evolved to signify a much lighter and brighter color, and is usually mixed from [[Phthalo Blue]] and [[titanium dioxide]], or from inexpensive synthetic blue dyes.

The discovery in 1856 of [[mauveine]], the first [[aniline dye]]s, was a forerunner for the development of hundreds of [[synthetic dye]]s and pigments like [[azo dye|azo]] and [[diazo]] compounds. These dyes ushered in the flourishing of organic chemistry, including systematic designs of colorants. The development of organic chemistry diminished the dependence on inorganic pigments.<ref>{{cite book |title=Mauve: How One Man Invented a Color That Changed the World |author=Simon Garfield |year=2000 |publisher=[[Faber and Faber]] |isbn=0-393-02005-3 |url=https://archive.org/details/mauvehowonemanin00garf}}</ref>
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According to Diana Magaloni, the Florentine Codex contains a variety of illustrations with multiple variations of the red pigments. Specifically in the case of ''achiotl (light red),'' technical analysis of the paint reveals multiple layers of the pigment although the layers of the pigment is not visible to the naked eye. Therefore, it proves that the process of applying multiple layers is more significant in comparison to the actual color itself. Furthermore, the process of layering the various hues of the same pigment on top of each other enabled the Aztec artists to create variations in the intensity of the subject matter. A bolder application of pigment draws the viewer's eye to the subject matter which commands attention and suggests a power of the viewer. A weaker application of pigment commands less attention and has less power. This would suggest that the Aztec associated the intensity of pigments with the idea of power and life.<ref>{{cite book |title=The Colors of The New World |last=Magaloni Kerpel |first=Diana |publisher=The Getty Research Institute |year=2014 |location=Los Angeles, CA |pages=35–40}}</ref>

Natives of [[Peru]] had been producing cochineal dyes for textiles since at least 700 CE,<ref>{{cite journal |title=Dye Analysis of Pre-Columbian Peruvian Textiles with High-Performance Liquid Chromatography and Diode-Array Detection |author=Jan Wouters, Noemi Rosario-Chirinos |year=1992 |volume=31 |issue=2 |pages=237–255 |journal=Journal of the American Institute for Conservation |doi=10.2307/3179495 |jstor=3179495 |publisher=The American Institute for Conservation of Historic &}}</ref> but Europeans had never seen the color before. When the Spanish invaded the [[Aztecs|Aztec empire]] in what is now [[Mexico]], they were quick to exploit the color for new trade opportunities. [[Carmine]] became the region's second-most-valuable export next to silver. Pigments produced from the cochineal insect gave the [[Cardinal (Catholicism)|Catholic cardinals]] their vibrant robes and the English "Redcoats" their distinctive uniforms. The true source of the pigment—an insect—was kept secret until the 18th century, when biologists discovered the source.<ref>{{cite book |title=A Perfect Red: Empire, Espionage, and the Quest for the Color of Desire |author=Amy Butler Greenfield |date=26 April 2005 |publisher=[[HarperCollins]] |isbn=0-06-052275-5 |url=https://archive.org/details/perfectred00amyb_0}}</ref>

[[File:1665 Girl with a Pearl Earring.jpg|thumb|''Girl with a Pearl Earring'' by [[Johannes Vermeer]] ({{circa|1665}}).]]

While carmine was popular in Europe, blue remained an exclusive color, associated with wealth and status. The 17th-century Dutch master [[Johannes Vermeer]] often made lavish use of [[lapis lazuli]], along with carmine and [[Indian yellow]], in his vibrant paintings.-->
<gallery caption="Paintings illustrating advances in pigments" widths="180px" heights="160px">
File:Johannes Vermeer - Het melkmeisje - Google Art Project.jpg|''The Milkmaid'' by [[Johannes Vermeer]] ({{circa|1658}}). Vermeer was lavish in his choice of expensive pigments, including [[lead-tin yellow]], natural [[ultramarine]], and [[madder lake]], as shown in the vibrant painting.<ref>[http://colourlex.com/project/vermeer-the-milkmaid/ Johannes Vermeer, The Milkmaid] {{webarchive|url=https://web.archive.org/web/20150414144606/http://colourlex.com/project/vermeer-the-milkmaid/ |date=14 April 2015}}, ColourLex</ref>
File:Tizian 041.jpg|[[Titian]] used the historic pigment [[vermilion]] to create the reds in the oil painting of [[Assumption of the Virgin (Titian)|Assunta]], completed {{circa|1518}}.
File:Tintoretto_-_Miracle_of_the_Slave.jpg|''Miracle of the Slave'' by [[Tintoretto]] ({{circa|1548}}). The son of a master [[dye]]r, Tintoretto used Carmine Red Lake pigment, derived from the [[cochineal]] insect, to achieve dramatic color effects.
File:Paul Cézanne 160.jpg|''Self Portrait'' by [[Paul Cézanne]]. Working in the late 19th century, Cézanne had a much broader palette of colors than his predecessors.
</gallery>

==Manufacturing and industrial standards==
[[File:Natural ultramarine pigment.jpg|thumb|Natural [[ultramarine]] pigment in powdered form]]
[[File:Ultramarinepigment.jpg|thumb|Synthetic ultramarine pigment is chemically identical to natural ultramarine]]
Before the development of synthetic pigments, and the refinement of techniques for extracting mineral pigments, batches of color were often inconsistent. With the development of a modern color industry, manufacturers and professionals have cooperated to create international standards for identifying, producing, measuring, and testing colors.

First published in 1905, the [[Munsell color system]] became the foundation for a series of color models, providing objective methods for the measurement of color. The Munsell system describes a color in three dimensions, [[hue]], [[lightness|value]] (lightness), and [[colorfulness|chroma]] (color purity), where chroma is the difference from gray at a given hue and value.

By the middle 20th century, standardized methods for pigment chemistry were available, part of an international movement to create such standards in industry. The [[International Organization for Standardization]] (ISO) develops technical standards for the manufacture of pigments and dyes. ISO standards define various industrial and chemical properties, and how to test for them. The principal ISO standards that relate to all pigments are as follows:
* ISO-787 General methods of test for pigments and extenders.
* ISO-8780 Methods of dispersion for assessment of dispersion characteristics.

Other ISO standards pertain to particular classes or categories of pigments, based on their chemical composition, such as [[ultramarine]] pigments, [[titanium dioxide]], iron oxide pigments, and so forth.

Many manufacturers of paints, inks, textiles, plastics, and colors have voluntarily adopted the [[Colour Index International]] (CII) as a standard for identifying the pigments that they use in manufacturing particular colors. First published in 1925—and now published jointly on the web by the [[Society of Dyers and Colourists]] ([[United Kingdom]]) and the [[American Association of Textile Chemists and Colorists]] (US)—this index is recognized internationally as the authoritative reference on colorants. It encompasses more than 27,000 products under more than 13,000 generic color index names.

In the CII schema, each pigment has a generic index number that identifies it chemically, regardless of proprietary and historic names. For example, [[Phthalocyanine Blue BN]] has been known by a variety of generic and proprietary names since its discovery in the 1930s. In much of Europe, phthalocyanine blue is better known as Helio Blue, or by a proprietary name such as Winsor Blue. An American paint manufacturer, Grumbacher, registered an alternate spelling (Thanos Blue) as a trademark. [[Colour Index International]] resolves all these conflicting historic, generic, and proprietary names so that manufacturers and consumers can identify the pigment (or dye) used in a particular color product. In the CII, all phthalocyanine blue pigments are designated by a generic color index number as either PB15 or PB16, short for pigment blue 15 and pigment blue 16; these two numbers reflect slight variations in molecular structure, which produce a slightly more greenish or reddish blue.

==Figures of merit==
The following are some of the attributes of pigments that determine their suitability for particular manufacturing processes and applications:
* [[Lightfastness]] and sensitivity for damage from ultraviolet light
* [[Heat stability]]
* [[Toxicity]]
* Tinting strength
* [[Staining]]
* [[Dispersion (chemistry)|Dispersion]] (which can be measured with a [[Hegman gauge]])
* [[Opacity (optics)|Opacity]] or [[transparency (optics)|transparency]]
* Resistance to alkalis and acids
* Reactions and interactions between pigments

==Swatches==
Swatches are used to communicate colors accurately. The types of swatches are dictated by the media, i.e., printing, computers, plastics, and textiles. Generally, the medium that offers the broadest gamut of color shades is widely used across diverse media.

===Printed swatches===
Reference standards are provided by printed swatches of color shades. [[PANTONE]], [[RAL colour standard|RAL]], [[Munsell color system|Munsell]], etc. are widely used standards of color communication across diverse media like printing, plastics, and [[textiles]].

===Plastic swatches===
Companies manufacturing [[masterbatch|color masterbatches]] and pigments for plastics offer plastic swatches in injection molded color chips. These color chips are supplied to the designer or customer to choose and select the color for their specific plastic products.

Plastic swatches are available in various special effects like pearl, metallic, fluorescent, sparkle, mosaic etc. However, these effects are difficult to replicate on other media like print and computer display. Plastic swatches have been created by 3D modelling to including various special effects.

===Computer swatches===
The appearance of pigments in natural light is difficult to replicate on a [[computer display]]. Approximations are required. The Munsell Color System provides an objective measure of color in three dimensions: hue, value (or lightness), and chroma. Computer displays in general fail to show the true chroma of many pigments, but the hue and lightness can be reproduced with relative accuracy. However, when the gamma of a computer display deviates from the reference value, the hue is also systematically biased.

The following approximations assume a display device at [[gamma correction|gamma]] 2.2, using the [[sRGB color space]]. The further a display device deviates from these standards, the less accurate these swatches will be.<ref>{{cite web |url=http://www.gamma-sci.com/dictionary-color-terms/ |title=Dictionary of Color Terms |publisher=Gamma Scientific |access-date=25 June 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140820184550/http://www.gamma-sci.com/dictionary-color-terms/ |archive-date=20 August 2014 |df=dmy-all}}</ref> Swatches are based on the average measurements of several lots of single-pigment watercolor paints, converted from [[Lab color space]] to [[sRGB color space]] for viewing on a computer display. The appearance of a pigment may depend on the brand and even the batch. Furthermore, pigments have inherently complex [[reflectance]] spectra that will render their color appearance<ref>{{cite web |url=http://helloartsy.com/color-appearance/ |title=Color Appearance |website=Hello Artsy |date=2 September 2013}}</ref>{{Better source needed|reason=Very little information here, let alone references to reliable sources.|date=February 2018}} greatly different depending on the spectrum of the [[standard illuminant|source illumination]], a property called [[metamerism (color)|metamerism]]. Averaged measurements of pigment samples will only yield approximations of their true appearance under a specific source of illumination. Computer display systems use a technique called chromatic adaptation transforms<ref>{{cite web |url=http://www2.cmp.uea.ac.uk/Research/compvis/ChromaticAdaptation/ChromaticAdaptation.htm |title=Chromatic Adaptation |publisher=cmp.uea.ac.uk |access-date=16 April 2009 |url-status=live |archive-url=https://web.archive.org/web/20070929155854/http://www2.cmp.uea.ac.uk/Research/compvis/ChromaticAdaptation/ChromaticAdaptation.htm |archive-date=29 September 2007}}</ref> to emulate the [[correlated color temperature]] of illumination sources, and cannot perfectly reproduce the intricate spectral combinations originally seen. In many cases, the perceived color of a pigment falls outside of the [[gamut]] of computer displays and a method called [[color management|gamut mapping]] is used to approximate the true appearance. Gamut mapping trades off any one of [[lightness]], [[hue]], or [[colorfulness|saturation]] accuracy to render the color on screen, depending on the priority chosen in the conversion's [[International Color Consortium|ICC]] [[rendering intent]].
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{| border="1" cellspacing="0"
|-
! <!-- A color swatch -->
<div class="thumb tleft">
<div style="width:125px;">
<div style="width:117px; height:50px; background:#990024; color:white;">#990024</div>
<div class="thumbcaption">[[Tyrian red]]<br></div>
</div></div>

! <!-- A color swatch -->
<div class="thumb tleft">
<div style="width:125px;">
<div style="width:117px; height:50px; background:#e34234; color:white;">PR106 – #E34234</div>
<div class="thumbcaption">{{Nowrap|[[Vermilion]] (genuine)}}</div>
</div></div>

! <!-- A color swatch -->
<div class="thumb tleft">
<div style="width:125px;">
<div style="width:117px; height:50px; background:#ffb02e; color:white;">#FFB02E</div>
<div class="thumbcaption">[[Indian yellow]]</div>
</div></div>
|}
{| border="1" cellspacing="0"
|-
! <!-- A color swatch -->
<div class="thumb tleft">
<div style="width:125px;">
<div style="width:117px; height:50px; background:#003baf; color:white;">PB29 – #003BAF</div>
<div class="thumbcaption">[[Ultramarine]] blue</div>
</div></div>
! <!-- A color swatch -->
<div class="thumb tleft">
<div style="width:125px;">
<div style="width:117px; height:50px; background:#0b3e66; color:white;">PB27 – #0B3E66</div>
<div class="thumbcaption">[[Prussian blue]]</div>
</div></div>
|}

==Biological pigments==
{{Main|Biological pigment}}
In [[biology]], a pigment is any [[color]]ed material of plant or animal cells. Many biological structures, such as [[skin]], [[eye]]s, [[fur]], and [[hair]] contain pigments (such as [[melanin]]).
[[Animal colouration|Animal skin coloration]] often comes about through specialized cells called [[chromatophore]]s, which animals such as the [[octopus]] and [[chameleon]] can control to vary the animal's color. Many conditions affect the levels or nature of pigments in plant, animal, some [[protista]], or [[fungus]] cells. For instance, the disorder called [[albinism]] affects the level of melanin production in animals.

Pigmentation in organisms serves many biological purposes, including [[camouflage]], [[mimicry]], [[aposematism]] (warning), [[sexual selection]] and other forms of [[signalling theory|signalling]], [[photosynthesis]] (in plants), and basic physical purposes such as protection from [[sunburn]].

Pigment color differs from [[color#Structural color|structural color]] in that pigment color is the same for all viewing angles, whereas structural color is the result of selective reflection or [[iridescence]], usually because of multilayer structures. For example, [[butterfly]] wings typically contain structural color, although many butterflies have cells that contain pigment as well.

=={{Anchor|Pigments by elemental composition}}Pigments by chemical composition==
[[File:Copper phthalocyanine.svg|thumb|right|200px|[[Phthalocyanine Blue BN|Phthalo Blue]]]]

{{Main|List of inorganic pigments}}
* [[Aluminium]] pigment: [[aluminum powder]]<ref>{{cite book |title=Engineer Manual 1110-2-3400 Painting: New Construction and Maintenance |date=30 April 1995 |pages=4–12 |url=https://www.publications.usace.army.mil/Portals/76/Publications/EngineerManuals/EM_1110-2-3400.pdf?ver=2013-09-04-070832-857 |access-date=24 November 2017 |url-status=live |archive-url=https://web.archive.org/web/20171201031655/http://www.publications.usace.army.mil/Portals/76/Publications/EngineerManuals/EM_1110-2-3400.pdf?ver=2013-09-04-070832-857 |archive-date=1 December 2017}}</ref>
* [[Barium]]: [[barium sulfate|barium white]] ([[lithopone]])
* [[Cadmium]] pigments: [[cadmium sulfide|cadmium yellow]], [[cadmium red]], [[cadmium pigments|cadmium green]], [[cadmium orange]], [[cadmium pigments|cadmium sulfoselenide]]
* [[Carbon]] pigments: [[carbon black]] (including vine black, lamp black), [[ivory black]] (bone charcoal)
* [[Chromium]] pigments: [[chrome yellow]] and [[viridian|chrome green (viridian)]]
* [[Cobalt]] pigments: [[cobalt violet]], [[cobalt blue]], [[cerulean blue]], [[aureolin]] (cobalt yellow)
* [[Copper]] pigments: [[azurite]], [[Han purple]], [[Han blue]], [[Egyptian blue]], [[malachite]], [[Paris green]], [[Phthalocyanine Blue BN]], [[Phthalocyanine Green G]], [[verdigris]]
* [[Iron oxide]] pigments: [[sanguine]], [[caput mortuum (pigment)|caput mortuum]], [[iron oxide red|oxide red]], [[red ochre]], [[yellow ochre]], [[Venetian red]], [[Prussian blue]], [[sienna|raw sienna]], [[burnt sienna]], [[raw umber]], [[burnt umber]]
* [[Lead]] pigments: [[lead white]], [[Naples yellow]], [[red lead]], [[lead-tin yellow]]
* [[Manganese]] pigments: [[manganese violet]], [[YInMn Blue|YInMn blue]]
* [[Mercury (element)|Mercury]] pigments: [[vermilion]]
* [[Sulfur]] pigments: [[ultramarine]], [[ultramarine green shade]], [[lapis lazuli]]
* [[Titanium]] pigments: [[titanium yellow]],  [[titanium white]], [[titanium black]]
* [[Zinc]] pigments: [[zinc white]], [[zinc ferrite]], [[zinc yellow]]

===Biological and organic===
* Biological origins: [[alizarin]], [[gamboge]], [[carmine|cochineal red]], [[rose madder]], [[indigo dye|indigo]], [[Indian yellow]], [[Tyrian purple]]
* Non-biological [[organic compound|organic]]: [[quinacridone]], [[magenta]], [[phthalo green]], [[phthalo blue]], [[pigment red 170]], [[diarylide yellow]]

==See also==
* [[Blue pigments]]
* [[Lake pigment]]
* [[List of Stone Age art]]
* [[Red pigments]]
* [[Rock art]]
* [[Subtractive color]]

==Notes==
{{Reflist|30em}}

==References==
* {{cite book |last=Ball |first=Philip |year=2002 |title=Bright Earth: Art and the Invention of Color |publisher=Farrar, Straus and Giroux |isbn=0-374-11679-2}}
* {{cite book |last=Doerner |first=Max |year=1984 |title=The Materials of the Artist and Their Use in Painting: With Notes on the Techniques of the Old Masters, Revised Edition. |publisher=Harcourt |isbn=0-15-657716-X}}
* {{cite book |last=Finlay |first=Victoria |year=2003 |title=Color: A Natural History of the Palette |publisher=Random House |isbn=0-8129-7142-6}}
* {{cite book |last=Gage |first=John |year=1999 |title=Color and Culture: Practice and Meaning from Antiquity to Abstraction |publisher=[[University of California Press]] |isbn=0-520-22225-3}}
* {{cite book |last=Meyer |first=Ralph |year=1991 |title=The Artist's Handbook of Materials and Techniques, Fifth Edition |publisher=Viking |isbn=0-670-83701-6 |url=https://archive.org/details/artistshandbooko00maye_0}}
* {{cite book |editor-first=R. L. |editor-last=Feller |title=Artists' Pigments. A Handbook of Their History and Characteristics, Vol. 1 |publisher=Cambridge University Press |location=London |year=1986}}
* {{cite book |editor-first=A. |editor-last=Roy |title=Artists' Pigments. A Handbook of Their History and Characteristics, Vol. 2 |publisher=Oxford University Press |year=1993}}
* {{cite book |editor-first=E. W. |editor-last=Fitzhugh |title=Artists' Pigments. A Handbook of Their History and Characteristics, Vol. 3 |publisher=Oxford University Press |year=1997}}
* {{cite book |editor-first=B. |editor-last=Berrie |title=Artists' Pigments. A Handbook of Their History and Characteristics, Vol. 4 |publisher=Archetype Books |year=2007}}

==External links==
{{Commons category|Pigments}}
{{Wikisource|1911 Encyclopædia Britannica/Pigments|Pigments}}
* [https://www.webexhibits.org/pigments/ Pigments through the ages]
* [https://colourlex.com/ ColourLex Pigment Lexicon]
* Sarah Lowengard,[http://www.gutenberg-e.org/lowengard/ The Creation of Color in Eighteenth-century Europe], Columbia University Press, 2006
* {{YouTube|r3kSeX32nsk|''Alchemy's Rainbow: Pigment Science and the Art of Conservation''}}, [[Chemical Heritage Foundation]]
* {{YouTube|lFF743BoQ3Q|''Poisons and Pigments: A Talk with Art Historian Elisabeth Berry-Drago''}}, [[Chemical Heritage Foundation]]
* [https://www.bloomberg.com/features/2018-quest-for-billion-dollar-red/ The Quest for the Next Billion-Dollar Color]

{{Prehistoric technology}}

{{Authority control}}
[[Category:Pigments| ]]
[[Category:Painting materials]]