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class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>History</span> </div> </a> <button aria-controls="toc-History-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle History subsection</span> </button> <ul id="toc-History-sublist" class="vector-toc-list"> <li id="toc-Synthetic_development" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Synthetic_development"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Synthetic development</span> </div> </a> <ul id="toc-Synthetic_development-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Dyeing_technology" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Dyeing_technology"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Dyeing technology</span> </div> </a> <button aria-controls="toc-Dyeing_technology-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Dyeing technology subsection</span> </button> <ul id="toc-Dyeing_technology-sublist" class="vector-toc-list"> <li id="toc-Indigo_white" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Indigo_white"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Indigo white</span> </div> </a> <ul id="toc-Indigo_white-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Direct_printing" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Direct_printing"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Direct printing</span> </div> </a> <ul id="toc-Direct_printing-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Chemical_properties" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Chemical_properties"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Chemical properties</span> </div> </a> <button aria-controls="toc-Chemical_properties-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Chemical properties subsection</span> </button> <ul id="toc-Chemical_properties-sublist" class="vector-toc-list"> <li id="toc-Indigo_derivatives" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Indigo_derivatives"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span>Indigo derivatives</span> </div> </a> <ul id="toc-Indigo_derivatives-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Indigo_as_an_organic_semiconductor" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Indigo_as_an_organic_semiconductor"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Indigo as an organic semiconductor</span> </div> </a> <ul id="toc-Indigo_as_an_organic_semiconductor-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Safety_and_the_environment" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Safety_and_the_environment"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Safety and the environment</span> </div> </a> <ul id="toc-Safety_and_the_environment-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Indigo dye</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 46 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-46" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">46 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%B5%D8%A8%D8%BA%D8%A9_%D8%A7%D9%84%D9%86%D9%8A%D9%84%D8%A9" title="صبغة النيلة – Arabic" lang="ar" hreflang="ar" data-title="صبغة النيلة" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-azb mw-list-item"><a href="https://azb.wikipedia.org/wiki/%D8%B1%D9%86%D9%82_%D9%86%DB%8C%D9%84" title="رنق نیل – South Azerbaijani" lang="azb" hreflang="azb" data-title="رنق نیل" data-language-autonym="تۆرکجه" data-language-local-name="South Azerbaijani" class="interlanguage-link-target"><span>تۆرکجه</span></a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%86%D0%BD%D0%B4%D1%8B%D0%B3%D0%B0" title="Індыга – Belarusian" lang="be" hreflang="be" data-title="Індыга" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target"><span>Беларуская</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%98%D0%BD%D0%B4%D0%B8%D0%B3%D0%BE" title="Индиго – Bulgarian" lang="bg" hreflang="bg" data-title="Индиго" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Indigo" title="Indigo – Bosnian" lang="bs" hreflang="bs" data-title="Indigo" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Indi_(colorant)" title="Indi (colorant) – Catalan" lang="ca" hreflang="ca" data-title="Indi (colorant)" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Indigo" title="Indigo – Czech" lang="cs" hreflang="cs" data-title="Indigo" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Indigo_(farvestof)" title="Indigo (farvestof) – Danish" lang="da" hreflang="da" data-title="Indigo (farvestof)" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de badge-Q17437796 badge-featuredarticle mw-list-item" title="featured article badge"><a href="https://de.wikipedia.org/wiki/Indigo" title="Indigo – German" lang="de" hreflang="de" data-title="Indigo" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Indigo" title="Indigo – Estonian" lang="et" hreflang="et" data-title="Indigo" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Colorante_%C3%ADndigo" title="Colorante índigo – Spanish" lang="es" hreflang="es" data-title="Colorante índigo" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Indigo_(farbo)" title="Indigo (farbo) – Esperanto" lang="eo" hreflang="eo" data-title="Indigo (farbo)" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Anil_(tindagaia)" title="Anil (tindagaia) – Basque" lang="eu" hreflang="eu" data-title="Anil (tindagaia)" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B1%D9%86%DA%AF%D8%B2%D8%A7%DB%8C_%D9%86%DB%8C%D9%84" title="رنگزای نیل – Persian" lang="fa" hreflang="fa" data-title="رنگزای نیل" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Indigo_(teinture)" title="Indigo (teinture) – French" lang="fr" hreflang="fr" data-title="Indigo (teinture)" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%9D%B8%EB%94%94%EA%B3%A0_(%EC%97%BC%EB%A3%8C)" title="인디고 (염료) – Korean" lang="ko" hreflang="ko" data-title="인디고 (염료)" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D4%BB%D5%B6%D5%A4%D5%AB%D5%A3%D5%B8" title="Ինդիգո – Armenian" lang="hy" hreflang="hy" data-title="Ինդիգո" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%A8%E0%A5%80%E0%A4%B2" title="नील – Hindi" lang="hi" hreflang="hi" data-title="नील" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Pewarna_indigo" title="Pewarna indigo – Indonesian" lang="id" hreflang="id" data-title="Pewarna indigo" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/Indig%C3%B3" title="Indigó – Icelandic" lang="is" hreflang="is" data-title="Indigó" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Indaco" title="Indaco – Italian" lang="it" hreflang="it" data-title="Indaco" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-kn mw-list-item"><a href="https://kn.wikipedia.org/wiki/%E0%B2%87%E0%B2%82%E0%B2%A1%E0%B2%BF%E0%B2%97%E0%B3%8B" title="ಇಂಡಿಗೋ – Kannada" lang="kn" hreflang="kn" data-title="ಇಂಡಿಗೋ" data-language-autonym="ಕನ್ನಡ" data-language-local-name="Kannada" class="interlanguage-link-target"><span>ಕನ್ನಡ</span></a></li><li class="interlanguage-link interwiki-lij mw-list-item"><a href="https://lij.wikipedia.org/wiki/Endegu_(tenta)" title="Endegu (tenta) – Ligurian" lang="lij" hreflang="lij" data-title="Endegu (tenta)" data-language-autonym="Ligure" data-language-local-name="Ligurian" class="interlanguage-link-target"><span>Ligure</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Indig%C3%B3_(k%C3%A9mia)" title="Indigó (kémia) – Hungarian" lang="hu" hreflang="hu" data-title="Indigó (kémia)" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Pewarna_nila" title="Pewarna nila – Malay" lang="ms" hreflang="ms" data-title="Pewarna nila" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Indigo_(kleurstof)" title="Indigo (kleurstof) – Dutch" lang="nl" hreflang="nl" data-title="Indigo (kleurstof)" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%82%A4%E3%83%B3%E3%83%87%E3%82%A3%E3%82%B4" title="インディゴ – Japanese" lang="ja" hreflang="ja" data-title="インディゴ" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/Indigo" title="Indigo – Uzbek" lang="uz" hreflang="uz" data-title="Indigo" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="Uzbek" class="interlanguage-link-target"><span>Oʻzbekcha / ўзбекча</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%87%E0%A9%B0%E0%A8%A1%E0%A9%80%E0%A8%97%E0%A9%8B_%E0%A8%A1%E0%A8%BE%E0%A8%88" title="ਇੰਡੀਗੋ ਡਾਈ – Punjabi" lang="pa" hreflang="pa" data-title="ਇੰਡੀਗੋ ਡਾਈ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="Punjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/%D9%86%DB%8C%D9%84_(%D9%85%D8%B1%DA%A9%D8%A8)" title="نیل (مرکب) – Western Punjabi" lang="pnb" hreflang="pnb" data-title="نیل (مرکب)" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target"><span>پنجابی</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Indygo" title="Indygo – Polish" lang="pl" hreflang="pl" data-title="Indygo" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Anil_(corante)" title="Anil (corante) – Portuguese" lang="pt" hreflang="pt" data-title="Anil (corante)" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%98%D0%BD%D0%B4%D0%B8%D0%B3%D0%BE" title="Индиго – Russian" lang="ru" hreflang="ru" data-title="Индиго" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Indigo_dye" title="Indigo dye – Simple English" lang="en-simple" hreflang="en-simple" data-title="Indigo dye" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Indigo_(chemick%C3%A1_l%C3%A1tka)" title="Indigo (chemická látka) – Slovak" lang="sk" hreflang="sk" data-title="Indigo (chemická látka)" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/Indigo_boja" title="Indigo boja – Serbian" lang="sr" hreflang="sr" data-title="Indigo boja" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Indigo_boja" title="Indigo boja – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Indigo boja" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Indigo_(f%C3%A4rg%C3%A4mne)" title="Indigo (färgämne) – Swedish" lang="sv" hreflang="sv" data-title="Indigo (färgämne)" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%A8%E0%B1%80%E0%B0%B2%E0%B0%BF%E0%B0%AE%E0%B0%82%E0%B0%A6%E0%B1%81" title="నీలిమందు – Telugu" lang="te" hreflang="te" data-title="నీలిమందు" data-language-autonym="తెలుగు" data-language-local-name="Telugu" class="interlanguage-link-target"><span>తెలుగు</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/%C4%B0ndigo_boya" title="İndigo boya – Turkish" lang="tr" hreflang="tr" data-title="İndigo boya" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-tk mw-list-item"><a href="https://tk.wikipedia.org/wiki/Indigo" title="Indigo – Turkmen" lang="tk" hreflang="tk" data-title="Indigo" data-language-autonym="Türkmençe" data-language-local-name="Turkmen" class="interlanguage-link-target"><span>Türkmençe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%86%D0%BD%D0%B4%D0%B8%D0%B3%D0%BE_(%D0%B1%D0%B0%D1%80%D0%B2%D0%BD%D0%B8%D0%BA)" title="Індиго (барвник) – Ukrainian" lang="uk" hreflang="uk" data-title="Індиго (барвник)" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D9%86%DB%8C%D9%84_(%D8%B1%D9%86%DA%AF)" title="نیل (رنگ) – Urdu" lang="ur" hreflang="ur" data-title="نیل (رنگ)" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target"><span>اردو</span></a></li><li class="interlanguage-link interwiki-vec mw-list-item"><a href="https://vec.wikipedia.org/wiki/%C3%8Cndigo_(co%C5%82orante)" title="Ìndigo (cołorante) – Venetian" lang="vec" hreflang="vec" data-title="Ìndigo (cołorante)" data-language-autonym="Vèneto" data-language-local-name="Venetian" class="interlanguage-link-target"><span>Vèneto</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Thu%E1%BB%91c_nhu%E1%BB%99m_m%C3%A0u_ch%C3%A0m" title="Thuốc nhuộm màu chàm – Vietnamese" lang="vi" hreflang="vi" data-title="Thuốc nhuộm màu chàm" 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</div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Chemical compound, food additive and dye</div> <style data-mw-deduplicate="TemplateStyles:r1084375498">.mw-parser-output .ib-chembox{border-collapse:collapse;text-align:left}.mw-parser-output .ib-chembox td,.mw-parser-output .ib-chembox th{border:1px solid #a2a9b1;width:40%}.mw-parser-output .ib-chembox td+td{width:60%}</style> <table class="infobox ib-chembox"> <caption>Indigo </caption> <tbody><tr> <td colspan="2" style="text-align:center; padding:2px;"><span typeof="mw:File"><a href="/wiki/File:Indian_indigo_dye_lump.jpg" class="mw-file-description"><img alt="Lump of Indian indigo dye" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Indian_indigo_dye_lump.jpg/220px-Indian_indigo_dye_lump.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Indian_indigo_dye_lump.jpg/330px-Indian_indigo_dye_lump.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Indian_indigo_dye_lump.jpg/440px-Indian_indigo_dye_lump.jpg 2x" data-file-width="800" data-file-height="600" /></a></span> </td></tr> <tr> <td colspan="2" style="text-align:center; padding:2px;"><span typeof="mw:File"><a href="/wiki/File:Indigo_skeletal.svg" class="mw-file-description"><img alt="Skeletal formula of indigo dye" src="//upload.wikimedia.org/wikipedia/commons/thumb/2/22/Indigo_skeletal.svg/220px-Indigo_skeletal.svg.png" decoding="async" width="220" height="123" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/22/Indigo_skeletal.svg/330px-Indigo_skeletal.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/22/Indigo_skeletal.svg/440px-Indigo_skeletal.svg.png 2x" data-file-width="287" data-file-height="160" /></a></span> </td></tr> <tr> <td colspan="2" style="text-align:center; padding:2px;"><span typeof="mw:File"><a href="/wiki/File:Indigo_dye_3D_ball.png" class="mw-file-description"><img alt="Ball-and-stick model of the indigo dye molecule" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Indigo_dye_3D_ball.png/220px-Indigo_dye_3D_ball.png" decoding="async" width="220" height="102" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Indigo_dye_3D_ball.png/330px-Indigo_dye_3D_ball.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Indigo_dye_3D_ball.png/440px-Indigo_dye_3D_ball.png 2x" data-file-width="2155" data-file-height="1000" /></a></span> </td></tr> <tr> <th colspan="2" style="background: #f8eaba; text-align: center;">Names </th></tr> <tr> <td colspan="2" style="text-align:left;"><a href="/wiki/Preferred_IUPAC_name" title="Preferred IUPAC name">Preferred IUPAC name</a> <div style="max-width:22em; word-wrap:break-word; padding-left:1.7em;"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0; max-width:22em;">[2(2')<i>E</i>]-[2,2'-Biindolylidene]-3,3'(1<i>H</i>,1'<i>H</i>)-dione</div></div> </td></tr> <tr> <td colspan="2" style="text-align:left;">Other names <div style="max-width:22em; word-wrap:break-word; padding-left:1.7em;">2,2'-Bis(2,3-dihydro-3-oxoindolyliden), Indigotin</div> </td></tr> <tr> <th colspan="2" style="background: #f8eaba; text-align: center;">Identifiers </th></tr> <tr> <td><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/wiki/CAS_Registry_Number" title="CAS Registry Number">CAS Number</a></div> </td> <td><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style><div class="plainlist"><ul><li><span title="commonchemistry.cas.org"><a rel="nofollow" class="external text" href="https://commonchemistry.cas.org/detail?cas_rn=64784-13-0">64784-13-0</a></span><sup> <span typeof="mw:File"><span><img alt="check" src="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/7px-Yes_check.svg.png" decoding="async" width="7" height="7" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/11px-Yes_check.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/14px-Yes_check.svg.png 2x" data-file-width="600" data-file-height="600" /></span></span><span style="display:none">Y</span></sup></li></ul></div> </td></tr> <tr> <td><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;">3D model (<a href="/wiki/JSmol" class="mw-redirect" title="JSmol">JSmol</a>)</div> </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li><span title="chemapps.stolaf.edu (3D interactive model)"><a rel="nofollow" class="external text" href="https://chemapps.stolaf.edu/jmol/jmol.php?model=c1ccc2c%28c1%29C%28%3DO%29%2FC%28%3DC%5C3%2FC%28%3DO%29c4ccccc4N3%29%2FN2">Interactive image</a></span></li></ul></div> </td></tr> <tr> <td><a href="/wiki/ChEMBL" title="ChEMBL">ChEMBL</a> </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li><span title="www.ebi.ac.uk"><a rel="nofollow" class="external text" href="https://www.ebi.ac.uk/chembl/explore/compound/ChEMBL599552">ChEMBL599552</a></span><sup> <span typeof="mw:File"><span><img alt="check" src="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/7px-Yes_check.svg.png" decoding="async" width="7" height="7" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/11px-Yes_check.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/14px-Yes_check.svg.png 2x" data-file-width="600" data-file-height="600" /></span></span><span style="display:none">Y</span></sup></li></ul></div> </td></tr> <tr> <td><a href="/wiki/ChemSpider" title="ChemSpider">ChemSpider</a> </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li><span title="www.chemspider.com"><a rel="nofollow" class="external text" href="https://www.chemspider.com/Chemical-Structure.4477009.html">4477009</a></span><sup> <span typeof="mw:File"><span><img alt="check" src="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/7px-Yes_check.svg.png" decoding="async" width="7" height="7" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/11px-Yes_check.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/14px-Yes_check.svg.png 2x" data-file-width="600" data-file-height="600" /></span></span><span style="display:none">Y</span></sup></li></ul></div> </td></tr> <tr> <td><a href="/wiki/ECHA_InfoCard" class="mw-redirect" title="ECHA InfoCard"><span title="echa.europa.eu">ECHA InfoCard</span></a> </td> <td><a rel="nofollow" class="external text" href="https://echa.europa.eu/substance-information/-/substanceinfo/100.006.898">100.006.898</a> <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q422662#P2566" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></span> </td></tr> <tr> <td><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/wiki/PubChem" title="PubChem">PubChem</a> <abbr title="Compound ID">CID</abbr></div> </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li><span title="pubchem.ncbi.nlm.nih.gov"><a rel="nofollow" class="external text" href="https://pubchem.ncbi.nlm.nih.gov/compound/10215">10215</a></span></li></ul></div> </td></tr> <tr> <td><a href="/wiki/RTECS" class="mw-redirect" title="RTECS">RTECS number</a> </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li>DU2988400</li></ul></div> </td></tr> <tr> <td><a href="/wiki/Unique_Ingredient_Identifier" title="Unique Ingredient Identifier">UNII</a> </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li><span title="precision.fda.gov"><a rel="nofollow" class="external text" href="https://precision.fda.gov/uniisearch/srs/unii/1G5BK41P4F">1G5BK41P4F</a></span><sup> <span typeof="mw:File"><span><img alt="check" src="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/7px-Yes_check.svg.png" decoding="async" width="7" height="7" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/11px-Yes_check.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/14px-Yes_check.svg.png 2x" data-file-width="600" data-file-height="600" /></span></span><span style="display:none">Y</span></sup></li></ul></div> </td></tr> <tr> <td><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/wiki/CompTox_Chemicals_Dashboard" title="CompTox Chemicals Dashboard">CompTox Dashboard</a> <span style="font-weight:normal">(<abbr title="U.S. Environmental Protection Agency">EPA</abbr>)</span></div> </td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><div class="plainlist"><ul><li><span title="comptox.epa.gov"><a rel="nofollow" class="external text" href="https://comptox.epa.gov/dashboard/chemical/details/DTXSID3026279">DTXSID3026279</a> <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q422662#P3117" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></span></span></li></ul></div> </td></tr> <tr> <td colspan="2"><div class="collapsible-list mw-collapsible mw-collapsed" style="text-align: left;"> <div style="line-height: 1.6em; font-weight: bold; text-align:left; font-weight:normal; background:transparent;"><div><a href="/wiki/International_Chemical_Identifier" title="International Chemical Identifier">InChI</a></div></div> <ul class="mw-collapsible-content" style="margin-top: 0; margin-bottom: 0; line-height: inherit; list-style: none; margin-left: 0; word-break:break-all;"><li style="line-height: inherit; margin: 0"><div style="border-top:1px solid #ccc; padding:0.2em 0 0.2em 1.5em; text-align:left;"><div style="word-wrap:break-word; text-indent:-1.5em; font-size:97%; line-height:120%;">InChI=1S/C16H10N2O2/c19-15-9-5-1-3-7-11(9)17-13(15)14-16(20)10-6-2-4-8-12(10)18-14/h1-8,17-18H/b14-13+<sup> <span typeof="mw:File"><span><img alt="check" src="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/7px-Yes_check.svg.png" decoding="async" width="7" height="7" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/11px-Yes_check.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/14px-Yes_check.svg.png 2x" data-file-width="600" data-file-height="600" /></span></span><span style="display:none">Y</span></sup></div><div style="word-wrap:break-word; text-indent:-1.5em; font-size:97%; line-height:120%;">Key: COHYTHOBJLSHDF-BUHFOSPRSA-N<sup> <span typeof="mw:File"><span><img alt="check" src="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/7px-Yes_check.svg.png" decoding="async" width="7" height="7" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/11px-Yes_check.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/14px-Yes_check.svg.png 2x" data-file-width="600" data-file-height="600" /></span></span><span style="display:none">Y</span></sup></div></div></li><li style="line-height: inherit; margin: 0"><div style="border-top:1px solid #ccc; padding:0.2em 0 0.2em 1.5em; text-align:left;"><div style="word-wrap:break-word; text-indent:-1.5em; font-size:97%; line-height:120%;">InChI=1/C16H10N2O2/c19-15-9-5-1-3-7-11(9)17-13(15)14-16(20)10-6-2-4-8-12(10)18-14/h1-8,17-18H/b14-13+</div><div style="word-wrap:break-word; text-indent:-1.5em; font-size:97%; line-height:120%;">Key: COHYTHOBJLSHDF-BUHFOSPRBQ</div></div></li></ul> </div> </td></tr> <tr> <td colspan="2"><div class="collapsible-list mw-collapsible mw-collapsed" style="text-align: left;"> <div style="line-height: 1.6em; font-weight: bold; text-align:left; font-weight:normal; background:transparent;"><div><a href="/wiki/Simplified_molecular-input_line-entry_system" class="mw-redirect" title="Simplified molecular-input line-entry system">SMILES</a></div></div> <ul class="mw-collapsible-content" style="margin-top: 0; margin-bottom: 0; line-height: inherit; list-style: none; margin-left: 0; word-break:break-all;"><li style="line-height: inherit; margin: 0"><div style="border-top:1px solid #ccc; padding:0.2em 0 0.2em 1.6em; word-wrap:break-word; text-indent:-1.5em; text-align:left; font-size:97%; line-height:120%;">c1ccc2c(c1)C(=O)/C(=C\3/C(=O)c4ccccc4N3)/N2</div></li></ul> </div> </td></tr> <tr> <th colspan="2" style="background: #f8eaba; text-align: center;">Properties </th></tr> <tr> <td><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/wiki/Chemical_formula" title="Chemical formula">Chemical formula</a></div> </td> <td>C<sub>16</sub>H<sub>10</sub>N<sub>2</sub>O<sub>2</sub>  </td></tr> <tr> <td><a href="/wiki/Molar_mass" title="Molar mass">Molar mass</a> </td> <td>262.27 g/mol    </td></tr> <tr> <td>Appearance </td> <td>dark blue crystalline powder </td></tr> <tr> <td><a href="/wiki/Density" title="Density">Density</a> </td> <td>1.199 g/cm<sup>3</sup> </td></tr> <tr> <td><a href="/wiki/Melting_point" title="Melting point">Melting point</a> </td> <td>390 to 392 °C (734 to 738 °F; 663 to 665 K) </td></tr> <tr> <td><a href="/wiki/Boiling_point" title="Boiling point">Boiling point</a> </td> <td>decomposes </td></tr> <tr> <td><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><a href="/wiki/Aqueous_solution" title="Aqueous solution">Solubility in water</a></div> </td> <td>990 µg/L (at 25 °C) </td></tr> <tr> <th colspan="2" style="background: #f8eaba; text-align: center;">Related compounds </th></tr> <tr> <td><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;">Related compounds</div> </td> <td><a href="/wiki/Indoxyl" title="Indoxyl">Indoxyl</a><br /><a href="/wiki/Tyrian_purple" title="Tyrian purple">Tyrian purple</a><br /><a href="/wiki/Indican" title="Indican">Indican</a> </td></tr> <tr> <td colspan="2" style="text-align:left; background:#f8eaba; border:1px solid #a2a9b1;"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;">Except where otherwise noted, data are given for materials in their <a href="/wiki/Standard_state" title="Standard state">standard state</a> (at 25 °C [77 °F], 100 kPa).</div> <div style="margin-top: 0.3em;"><div style="text-align:center;"><span typeof="mw:File"><span><img alt="check" src="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/12px-Yes_check.svg.png" decoding="async" width="12" height="12" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/18px-Yes_check.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/24px-Yes_check.svg.png 2x" data-file-width="600" data-file-height="600" /></span></span><span style="display:none">Y</span> <span class="reflink plainlinks nourlexpansion"><a class="external text" href="https://en.wikipedia.org/w/index.php?title=Special:ComparePages&rev1=477315345&page2=Indigo+dye">verify</a></span> (<a href="/wiki/Wikipedia:WikiProject_Chemicals/Chembox_validation" title="Wikipedia:WikiProject Chemicals/Chembox validation">what is</a> <sup><span typeof="mw:File"><span><img alt="check" src="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/7px-Yes_check.svg.png" decoding="async" width="7" height="7" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/11px-Yes_check.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/fb/Yes_check.svg/14px-Yes_check.svg.png 2x" data-file-width="600" data-file-height="600" /></span></span><span style="display:none">Y</span><span typeof="mw:File"><span><img alt="☒" src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a2/X_mark.svg/7px-X_mark.svg.png" decoding="async" width="7" height="8" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a2/X_mark.svg/11px-X_mark.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a2/X_mark.svg/14px-X_mark.svg.png 2x" data-file-width="525" data-file-height="600" /></span></span><span style="display:none">N</span></sup> ?) </div></div> <div style="margin-top: 0.3em; text-align: center;"><a href="/wiki/Wikipedia:Chemical_infobox#References" title="Wikipedia:Chemical infobox">Infobox references</a></div> </td></tr> </tbody></table><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Chemical compound</div> <p><b>Indigo dye</b> is an <a href="/wiki/Organic_compound" title="Organic compound">organic compound</a> with a distinctive <a href="/wiki/Indigo" title="Indigo">blue color</a>. Indigo is a <a href="/wiki/Natural_dye" title="Natural dye">natural dye</a> extracted from the leaves of some plants of the <a href="/wiki/Indigofera#Uses" title="Indigofera"><i>Indigofera</i></a> genus, in particular <i><a href="/wiki/Indigofera_tinctoria" title="Indigofera tinctoria">Indigofera tinctoria</a></i>. Dye-bearing <i>Indigofera</i> plants were commonly grown and used throughout the world, particularly in Asia, with the production of indigo dyestuff economically important due to the historical rarity of other blue dyestuffs.<sup id="cite_ref-Ullmann_1-0" class="reference"><a href="#cite_note-Ullmann-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>Most indigo <a href="/wiki/Dye" title="Dye">dye</a> produced today is <a href="/wiki/Chemical_synthesis" title="Chemical synthesis">synthetic</a>, constituting around 80,000 tonnes each year, as of 2023.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> It is most commonly associated with the production of <a href="/wiki/Denim" title="Denim">denim</a> cloth and <a href="/wiki/Jeans" title="Jeans">blue jeans</a>, where its properties allow for effects such as <a href="/wiki/Stone_washing" title="Stone washing">stone washing</a> and <a href="/wiki/Stone_washing#Acid-washed_jeans" title="Stone washing">acid washing</a> to be applied quickly. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Uses">Uses</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=1" title="Edit section: Uses"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:Indigo_plant_extract_sample.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/1/18/Indigo_plant_extract_sample.jpg/140px-Indigo_plant_extract_sample.jpg" decoding="async" width="140" height="139" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/18/Indigo_plant_extract_sample.jpg/210px-Indigo_plant_extract_sample.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/1/18/Indigo_plant_extract_sample.jpg 2x" data-file-width="230" data-file-height="228" /></a><figcaption>Indigo dye</figcaption></figure> <p>The primary use for indigo is as a dye for cotton yarn, mainly used in the production of denim cloth suitable for blue jeans; on average, a pair of blue jeans requires 3 grams (0.11 oz) to 12 grams (0.42 oz) of dye. Smaller quantities are used in the dyeing of wool and silk. </p><p><a href="/wiki/Indigo_carmine" title="Indigo carmine">Indigo carmine</a>, also known as indigo, is an indigo derivative which is also used as a colorant. About 20,000 tonnes are produced annually, again mainly for the production of blue jeans.<sup id="cite_ref-Ullmann_1-1" class="reference"><a href="#cite_note-Ullmann-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> It is also used as a food colorant, and is listed in the United States as <a href="/wiki/FD%26C" class="mw-redirect" title="FD&C">FD&C</a> Blue No. 2. </p> <div class="mw-heading mw-heading2"><h2 id="Sources">Sources</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=2" title="Edit section: Sources"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Natural_sources">Natural sources</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=3" title="Edit section: Natural sources"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">See also: <a href="#Indigo_derivatives">§ Indigo derivatives</a></div> <p>A variety of plants have provided indigo throughout history, but most natural indigo was obtained from those in the genus <i>Indigofera</i>, which are native to the tropics, notably the Indian Subcontinent. The primary commercial indigo species in Asia was true indigo (<i><a href="/wiki/Indigofera_tinctoria" title="Indigofera tinctoria">Indigofera tinctoria</a></i>, also known as <i>I. sumatrana</i>). A common alternative used in the relatively colder subtropical locations such as Japan's <span title="Japanese-language text"><span lang="ja-Latn" style="font-style: normal;">Ryukyu</span></span> Islands and Taiwan is <i><a href="/wiki/Strobilanthes_cusia" title="Strobilanthes cusia">Strobilanthes cusia</a></i>. </p><p>Until the introduction of <i>Indigofera</i> species from the south, <i><a href="/wiki/Polygonum_tinctorum" class="mw-redirect" title="Polygonum tinctorum">Persicaria tinctoria</a></i> (dyer's knotweed) was the most important blue dyestuff in East Asia; however, the crop produced less dyestuff than the average crop of indigo, and was quickly surpassed in favour of the more economical <i>Indigofera tinctoria</i> plant. In <a href="/wiki/Central_America" title="Central America">Central</a> and South America, the species grown is <i><a href="/wiki/Indigofera_suffruticosa" title="Indigofera suffruticosa">Indigofera suffruticosa</a></i>, also known as <i>anil</i>, and in India, an important species was <i><a href="/wiki/Indigofera_arrecta" title="Indigofera arrecta">Indigofera arrecta</a></i>, Natal indigo. In Europe, <i><a href="/wiki/Isatis_tinctoria" title="Isatis tinctoria">Isatis tinctoria</a></i>, commonly known as woad, was used for dyeing fabrics blue, containing the same dyeing compounds as indigo, also referred to as indigo. </p><p>Several plants contain indigo, which, when exposed to an oxidizing source such as atmospheric oxygen, reacts to produce indigo dye; however, the relatively low concentrations of indigo in these plants make them difficult to work with, with the color more easily tainted by other dye substances also present in these plants, typically leading to a greenish tinge. </p><p>The precursor to indigo is <a href="/wiki/Indican" title="Indican">indican</a>, a colorless, water-soluble derivative of the amino acid <a href="/wiki/Tryptophan" title="Tryptophan">tryptophan</a>, and <i>Indigofera</i> leaves contain as much as 0.2–0.8% of this compound. Pressing cut leaves into a vat and soaking hydrolyzes the indican, releasing β-<span class="smallcaps"><span style="font-variant: small-caps; text-transform: lowercase;">D</span></span>-<a href="/wiki/Glucose" title="Glucose">glucose</a> and <a href="/wiki/Indoxyl" title="Indoxyl">indoxyl</a>. The indoxyl dimerizes in the mixture, and after 12–15 hours of <a href="/wiki/Fermentation" title="Fermentation">fermentation</a> yields the yellow, water-soluble <a href="/wiki/Leuco_dye" title="Leuco dye">leucoindigo</a>. Subsequent exposure to air forms the blue, water-insoluble indigo dye.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> The dye precipitates from the fermented leaf solution upon oxidation, but may also be precipitated when mixed with a strong base<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> such as <a href="/wiki/Sodium_hydroxide" title="Sodium hydroxide">lye</a>. The solids are filtered, pressed into cakes, dried, and powdered. The powder is then mixed with various other substances to produce different shades of blue and purple. </p><p>Natural sources of indigo also include mollusks: the <i><a href="/wiki/Murex" title="Murex">Murex</a></i> genus of sea snails produces a mixture of indigo and <a href="/wiki/6,6%27-Dibromoindigo" title="6,6'-Dibromoindigo">6,6'-dibromoindigo</a> (red), which together produce a range of purple hues known as <a href="/wiki/Tyrian_purple" title="Tyrian purple">Tyrian purple</a>. Light exposure during part of the dyeing process can convert the dibromoindigo into indigo, resulting in blue hues known as royal blue, hyacinth purple, or <a href="/wiki/Tekhelet" title="Tekhelet">tekhelet</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Chemical_synthesis">Chemical synthesis</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=4" title="Edit section: Chemical synthesis"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1237032888/mw-parser-output/.tmulti">.mw-parser-output .tmulti .multiimageinner{display:flex;flex-direction:column}.mw-parser-output .tmulti .trow{display:flex;flex-direction:row;clear:left;flex-wrap:wrap;width:100%;box-sizing:border-box}.mw-parser-output .tmulti .tsingle{margin:1px;float:left}.mw-parser-output .tmulti .theader{clear:both;font-weight:bold;text-align:center;align-self:center;background-color:transparent;width:100%}.mw-parser-output .tmulti .thumbcaption{background-color:transparent}.mw-parser-output .tmulti .text-align-left{text-align:left}.mw-parser-output .tmulti .text-align-right{text-align:right}.mw-parser-output .tmulti .text-align-center{text-align:center}@media all and (max-width:720px){.mw-parser-output .tmulti .thumbinner{width:100%!important;box-sizing:border-box;max-width:none!important;align-items:center}.mw-parser-output .tmulti .trow{justify-content:center}.mw-parser-output .tmulti .tsingle{float:none!important;max-width:100%!important;box-sizing:border-box;text-align:center}.mw-parser-output .tmulti .tsingle .thumbcaption{text-align:left}.mw-parser-output .tmulti .trow>.thumbcaption{text-align:center}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .tmulti .multiimageinner img{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .tmulti .multiimageinner img{background-color:white}}</style><div class="thumb tmulti tright"><div class="thumbinner multiimageinner" style="width:334px;max-width:334px"><div class="trow"><div class="tsingle" style="width:332px;max-width:332px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Indigo.Baeyer-Drewson.Synthesis.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/04/Indigo.Baeyer-Drewson.Synthesis.svg/330px-Indigo.Baeyer-Drewson.Synthesis.svg.png" decoding="async" width="330" height="64" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/04/Indigo.Baeyer-Drewson.Synthesis.svg/495px-Indigo.Baeyer-Drewson.Synthesis.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/04/Indigo.Baeyer-Drewson.Synthesis.svg/660px-Indigo.Baeyer-Drewson.Synthesis.svg.png 2x" data-file-width="918" data-file-height="177" /></a></span></div><div class="thumbcaption">Heumann's synthesis of indigo</div></div></div><div class="trow"><div class="tsingle" style="width:332px;max-width:332px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Indigo_Synthesis_V.1.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Indigo_Synthesis_V.1.svg/330px-Indigo_Synthesis_V.1.svg.png" decoding="async" width="330" height="59" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Indigo_Synthesis_V.1.svg/495px-Indigo_Synthesis_V.1.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Indigo_Synthesis_V.1.svg/660px-Indigo_Synthesis_V.1.svg.png 2x" data-file-width="1170" data-file-height="210" /></a></span></div><div class="thumbcaption">Pfleger's synthesis of indigo</div></div></div></div></div> <p>Given its economic importance, indigo has been prepared by many methods. The <a href="/wiki/Baeyer%E2%80%93Drewsen_indigo_synthesis" title="Baeyer–Drewsen indigo synthesis">Baeyer–Drewsen indigo synthesis</a> dates back to 1882. It involves an aldol condensation of o-nitrobenzaldehyde with acetone, followed by cyclization and oxidative dimerization to indigo. This route was highly useful for obtaining indigo and many of its derivatives on the laboratory scale, but proved impractical for industrial-scale synthesis. Johannes Pfleger<sup id="cite_ref-history.evonik.com_6-0" class="reference"><a href="#cite_note-history.evonik.com-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> and <a href="/w/index.php?title=Karl_Heumann&action=edit&redlink=1" class="new" title="Karl Heumann (page does not exist)">Karl Heumann</a><span class="noprint" style="font-size:85%; font-style: normal;"> [<a href="https://de.wikipedia.org/wiki/Karl_Heumann" class="extiw" title="de:Karl Heumann">de</a>]</span> eventually came up with industrial mass production synthesis from <a href="/wiki/Aniline" title="Aniline">aniline</a> by using <a href="/wiki/Mercury_(element)" title="Mercury (element)">mercury</a> as a catalyst. The method was discovered by an accident by Karl Heumann in Zurich which involved a broken thermometer.<sup id="cite_ref-ingenious.org.uk_7-0" class="reference"><a href="#cite_note-ingenious.org.uk-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p><p>The first commercially practical route of producing indigo is credited to Pfleger in 1901. In this process, <a href="/wiki/N-Phenylglycine" title="N-Phenylglycine"><i>N</i>-phenylglycine</a> is treated with a molten mixture of <a href="/wiki/Sodium_hydroxide" title="Sodium hydroxide">sodium hydroxide</a>, <a href="/wiki/Potassium_hydroxide" title="Potassium hydroxide">potassium hydroxide</a>, and <a href="/wiki/Sodamide" class="mw-redirect" title="Sodamide">sodamide</a>. This highly sensitive melt produces <a href="/wiki/Indoxyl" title="Indoxyl">indoxyl</a>, which is subsequently oxidized in air to form indigo. Variations of this method are still in use today. An alternative and also viable route to indigo is credited to Heumann in 1897. It involves heating <i>N</i>-(2-carboxyphenyl)glycine to 200 °C (392 °F) in an inert atmosphere with sodium hydroxide. The process is easier than the Pfleger method, but the precursors are more expensive. Indoxyl-2-carboxylic acid is generated. This material readily decarboxylates to give indoxyl, which oxidizes in air to form indigo.<sup id="cite_ref-Ullmann_1-2" class="reference"><a href="#cite_note-Ullmann-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The preparation of indigo dye is practised in college laboratory classes according to the original Baeyer-Drewsen route.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=5" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Indigo-Historische_Farbstoffsammlung.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2d/Indigo-Historische_Farbstoffsammlung.jpg/220px-Indigo-Historische_Farbstoffsammlung.jpg" decoding="async" width="220" height="99" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2d/Indigo-Historische_Farbstoffsammlung.jpg/330px-Indigo-Historische_Farbstoffsammlung.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2d/Indigo-Historische_Farbstoffsammlung.jpg/440px-Indigo-Historische_Farbstoffsammlung.jpg 2x" data-file-width="3329" data-file-height="1505" /></a><figcaption>Indigo, historical dye collection of the <a href="/wiki/Dresden_University_of_Technology" class="mw-redirect" title="Dresden University of Technology">Technical University of Dresden</a>, Germany</figcaption></figure> <p><br /> The oldest known fabric dyed indigo, dated to 6,000 years ago, was discovered in <a href="/wiki/Huaca_Prieta" title="Huaca Prieta">Huaca Prieta</a>, Peru.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> Many Asian countries, such as <a href="/wiki/India" title="India">India</a>, China, Japan, and <a href="/wiki/Southeast_Asia" title="Southeast Asia">Southeast Asian</a> nations have used indigo as a dye (particularly for <a href="/wiki/Silk" title="Silk">silk</a>) for centuries. The dye was also known to ancient civilizations in <a href="/wiki/Mesopotamia" title="Mesopotamia">Mesopotamia</a>, <a href="/wiki/Ancient_Egypt" title="Ancient Egypt">Egypt</a>, <a href="/wiki/Prehistoric_Britain" title="Prehistoric Britain">Britain</a>, <a href="/wiki/Mesoamerica" title="Mesoamerica">Mesoamerica</a>, <a href="/wiki/Peru" title="Peru">Peru</a>, <a href="/wiki/Iran" title="Iran">Iran</a>, and <a href="/wiki/West_Africa" title="West Africa">West Africa</a>. Indigo was also cultivated in India, which was also the earliest major center for its production and processing.<sup id="cite_ref-k&c_10-0" class="reference"><a href="#cite_note-k&c-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> The <i><a href="/wiki/Indigofera_tinctoria" title="Indigofera tinctoria">Indigofera tinctoria</a></i> species was domesticated in India.<sup id="cite_ref-k&c_10-1" class="reference"><a href="#cite_note-k&c-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> Indigo, used as a dye, made its way to the <a href="/wiki/Ancient_Greece" title="Ancient Greece">Greeks</a> and the <a href="/wiki/Ancient_Rome" title="Ancient Rome">Romans</a>, where it was valued as a luxury product.<sup id="cite_ref-k&c_10-2" class="reference"><a href="#cite_note-k&c-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Indigo_cake.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Indigo_cake.jpg/220px-Indigo_cake.jpg" decoding="async" width="220" height="220" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Indigo_cake.jpg/330px-Indigo_cake.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Indigo_cake.jpg/440px-Indigo_cake.jpg 2x" data-file-width="2000" data-file-height="2000" /></a><figcaption>Cake of indigo, about 2 cm</figcaption></figure> <p>In Mesopotamia, a neo-Babylonian <a href="/wiki/Cuneiform" title="Cuneiform">cuneiform</a> tablet of the seventh century BC gives a recipe for the dyeing of wool, where <a href="/wiki/Lapis_lazuli" title="Lapis lazuli">lapis</a>-colored wool (<i>uqnatu</i>) is produced by repeated immersion and airing of the cloth.<sup id="cite_ref-StClair_11-0" class="reference"><a href="#cite_note-StClair-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> Indigo was most probably imported from India. The Romans used indigo as a pigment for painting and for medicinal and cosmetic purposes. It was a luxury item imported to the Mediterranean from India by Arab merchants. </p><p>India was a primary supplier of indigo to Europe as early as the Greco-Roman era. The association of India with indigo is reflected in the Greek word for the dye, <i>indikón</i> (<span title="Ancient Greek (to 1453)-language text"><span lang="grc">Ἰνδικόν</span></span>, Indian).<sup id="cite_ref-StClair_11-1" class="reference"><a href="#cite_note-StClair-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> The Romans <a href="/wiki/Latin" title="Latin">latinized</a> the term to <i>indicum</i>, which passed into <a href="/wiki/Venetian_language" title="Venetian language">Italian dialect</a> and eventually into English as the word indigo. </p><p>In <a href="/wiki/Bengal_Presidency" title="Bengal Presidency">Bengal</a> indigo cultivators revolted against exploitative working conditions created by European merchants and planters in what became known as the <a href="/wiki/Indigo_revolt" title="Indigo revolt">Indigo revolt</a> in 1859. The Bengali play <i><a href="/wiki/Nil_Darpan" title="Nil Darpan">Nil Darpan</a></i> by Indian playwright <a href="/wiki/Dinabandhu_Mitra" title="Dinabandhu Mitra">Dinabandhu Mitra</a> was a fictionalized retelling of the revolt. </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Ridpath%27s_history_of_the_world;_being_an_account_of_the_ethnic_origin,_primitive_estate,_early_migrations,_social_conditions_and_present_promise_of_the_principal_families_of_men_(1897)_(14597001160).jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Ridpath%27s_history_of_the_world%3B_being_an_account_of_the_ethnic_origin%2C_primitive_estate%2C_early_migrations%2C_social_conditions_and_present_promise_of_the_principal_families_of_men_%281897%29_%2814597001160%29.jpg/220px-thumbnail.jpg" decoding="async" width="220" height="152" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Ridpath%27s_history_of_the_world%3B_being_an_account_of_the_ethnic_origin%2C_primitive_estate%2C_early_migrations%2C_social_conditions_and_present_promise_of_the_principal_families_of_men_%281897%29_%2814597001160%29.jpg/330px-thumbnail.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Ridpath%27s_history_of_the_world%3B_being_an_account_of_the_ethnic_origin%2C_primitive_estate%2C_early_migrations%2C_social_conditions_and_present_promise_of_the_principal_families_of_men_%281897%29_%2814597001160%29.jpg/440px-thumbnail.jpg 2x" data-file-width="2218" data-file-height="1534" /></a><figcaption>Indigo factory at <a href="/wiki/Allahabad" class="mw-redirect" title="Allahabad">Allahabad</a>, India, drawn by <a href="/w/index.php?title=%C3%89mile_Th%C3%A9rond&action=edit&redlink=1" class="new" title="Émile Thérond (page does not exist)">Émile Thérond</a><span class="noprint" style="font-size:85%; font-style: normal;"> [<a href="https://fr.wikipedia.org/wiki/%C3%89mile_Th%C3%A9rond" class="extiw" title="fr:Émile Thérond">fr</a>]</span>, 19th century</figcaption></figure> <p>The demand for indigo in the 19th century is indicated by the fact that in 1897, 7,000 km<sup>2</sup> (2,700 sq mi) were dedicated to the cultivation of indican-producing plants, mainly in <a href="/wiki/India" title="India">India</a>. By comparison, the country of <a href="/wiki/Luxembourg" title="Luxembourg">Luxembourg</a> is 2,586 km<sup>2</sup> (998 sq mi).<sup id="cite_ref-Ullmann_1-3" class="reference"><a href="#cite_note-Ullmann-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>In Europe, indigo remained a rare commodity throughout the Middle Ages. A chemically identical dye derived from the woad plant <i>(<a href="/wiki/Isatis_tinctoria" title="Isatis tinctoria">Isatis tinctoria</a>)</i> was used instead. In the late 15th century, the <a href="/wiki/Portugal" title="Portugal">Portuguese</a> explorer <a href="/wiki/Vasco_da_Gama" title="Vasco da Gama">Vasco da Gama</a> discovered a sea route to India. This led to the establishment of direct trade with India, the <a href="/wiki/Maluku_Islands" title="Maluku Islands">Spice Islands</a>, China, and Japan. Importers could now avoid the heavy duties imposed by <a href="/wiki/Iran" title="Iran">Persian</a>, <a href="/wiki/Levant" title="Levant">Levantine</a>, and Greek middlemen and the lengthy and dangerous land routes which had previously been used. Consequently, the importation and use of indigo in Europe rose significantly. Much European indigo from Asia arrived through ports in Portugal, the Netherlands, and England. Many indigo plantations were established by European powers in tropical climates. Spain imported the dye from its colonies in Central and South America, and it was a major crop in <a href="/wiki/Haiti" title="Haiti">Haiti</a> and Jamaica, with much or all of the labor performed by enslaved Africans and African Americans. In the Spanish colonial era, intensive production of indigo for the world market in the region of modern El Salvador entailed such unhealthy conditions that the local indigenous population, forced to labor in pestilential conditions, was decimated.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> Indigo plantations also thrived in the <a href="/wiki/Virgin_Islands" title="Virgin Islands">Virgin Islands</a>. However, France and Germany outlawed imported indigo in the 16th century to protect the local woad dye industry. In central Europe, indigo resist dyeing is a centuries-old skill that has received UNESCO Intangible Cultural Heritage of Humanity recognition.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </p><p><a href="/wiki/Isaac_Newton" title="Isaac Newton">Newton</a> used "indigo" to describe one of the two new <a href="/wiki/Primary_color" title="Primary color">primary colors</a> he added to the five he had originally named, in his revised account of the rainbow in <i>Lectiones Opticae</i> of 1675.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </p><p>Because of its high value as a trading commodity, indigo was often referred to as blue gold.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Touaregs_at_the_Festival_au_Desert_near_Timbuktu,_Mali_2012.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Touaregs_at_the_Festival_au_Desert_near_Timbuktu%2C_Mali_2012.jpg/220px-Touaregs_at_the_Festival_au_Desert_near_Timbuktu%2C_Mali_2012.jpg" decoding="async" width="220" height="146" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Touaregs_at_the_Festival_au_Desert_near_Timbuktu%2C_Mali_2012.jpg/330px-Touaregs_at_the_Festival_au_Desert_near_Timbuktu%2C_Mali_2012.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Touaregs_at_the_Festival_au_Desert_near_Timbuktu%2C_Mali_2012.jpg/440px-Touaregs_at_the_Festival_au_Desert_near_Timbuktu%2C_Mali_2012.jpg 2x" data-file-width="5212" data-file-height="3468" /></a><figcaption><a href="/wiki/Tuareg_people" title="Tuareg people">Tuaregs</a> wearing the indigo-dyed <a href="/wiki/Tagelmust" class="mw-redirect" title="Tagelmust">tagelmust</a></figcaption></figure> <p>Throughout West Africa, Indigo was the foundation of centuries-old textile traditions. From the <a href="/wiki/Tuareg_people" title="Tuareg people">Tuareg</a> nomads of the <a href="/wiki/Sahara" title="Sahara">Sahara</a> to <a href="/wiki/Cameroon" title="Cameroon">Cameroon</a>, clothes dyed with indigo signified wealth. Women dyed the cloth in most areas, with the <a href="/wiki/Yoruba_people" title="Yoruba people">Yoruba</a> of <a href="/wiki/Nigeria" title="Nigeria">Nigeria</a> and the <a href="/wiki/Mandinka_people" title="Mandinka people">Mandinka</a> of <a href="/wiki/Mali" title="Mali">Mali</a> particularly well known for their expertise. Among the <a href="/wiki/Hausa_people" title="Hausa people">Hausa</a> male dyers, working at communal dye pits was the basis of the wealth of the ancient city of <a href="/wiki/Kano_(city)" title="Kano (city)">Kano</a>, and they can still be seen plying their trade today at the same pits.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> The Tuareg are sometimes called the "Blue People" because the <a href="/wiki/Indigo" title="Indigo">indigo</a> pigment in the cloth of their traditional robes and turbans stained their skin dark blue.<sup id="cite_ref-GearonEamonn_17-0" class="reference"><a href="#cite_note-GearonEamonn-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> </p><p>In Japan, indigo became especially important during the <a href="/wiki/Edo_period" title="Edo period">Edo period</a>. This was due to a growing textiles industry,<sup id="cite_ref-Ikegami2005_18-0" class="reference"><a href="#cite_note-Ikegami2005-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> and because commoners had been banned from wearing silk,<sup id="cite_ref-Sagers2018_19-0" class="reference"><a href="#cite_note-Sagers2018-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> leading to the increasing cultivation of cotton, and consequently indigo – one of the few substances that could dye it.<sup id="cite_ref-Wassenaar2011_20-0" class="reference"><a href="#cite_note-Wassenaar2011-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p><p>In North America, indigo was introduced into colonial South Carolina by <a href="/wiki/Eliza_Lucas" title="Eliza Lucas">Eliza Lucas</a>, where it became the colony's second-most important cash crop (after rice).<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> As a major export crop, indigo supported plantation slavery there.<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> In the May and June 1755 issues of <i><a href="/wiki/The_Gentleman%27s_Magazine" title="The Gentleman's Magazine">The Gentleman's Magazine</a>,</i> there appeared a detailed account of the cultivation of indigo, accompanied by drawings of necessary equipment and a prospective budget for starting such an operation, authored by South Carolina planter <a href="/wiki/Charles_Woodmason" title="Charles Woodmason">Charles Woodmason</a>. It later appeared as a book.<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-24" class="reference"><a href="#cite_note-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> By 1775, indigo production in South Carolina exceeded 1,222,000 pounds.<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> When <a href="/wiki/Benjamin_Franklin" title="Benjamin Franklin">Benjamin Franklin</a> sailed to France in November 1776 to enlist France's support for the <a href="/wiki/American_Revolutionary_War" title="American Revolutionary War">American Revolutionary War</a>, 35 barrels of indigo were on board the <a href="/wiki/USS_Reprisal_(1776)" title="USS Reprisal (1776)"><i>Reprisal</i></a>, the sale of which would help fund the war effort.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> In colonial North America, three commercially important species are found: the native <i>I. caroliniana</i>, and the introduced <i>I. tinctoria</i> and <i>I. suffruticosa</i>.<sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Synthetic_development">Synthetic development</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=6" title="Edit section: Synthetic development"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Indigoproduktion_BASF_1890.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6c/Indigoproduktion_BASF_1890.JPG/220px-Indigoproduktion_BASF_1890.JPG" decoding="async" width="220" height="155" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6c/Indigoproduktion_BASF_1890.JPG/330px-Indigoproduktion_BASF_1890.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/6/6c/Indigoproduktion_BASF_1890.JPG 2x" data-file-width="351" data-file-height="247" /></a><figcaption>Production of Indigo dye in a <a href="/wiki/BASF" title="BASF">BASF</a> plant (1890)</figcaption></figure> <p>In 1865 the German chemist <a href="/wiki/Adolf_von_Baeyer" title="Adolf von Baeyer">Adolf von Baeyer</a> began working on the synthesis of indigo. He described his first synthesis of indigo in 1878 (from <a href="/wiki/Isatin" title="Isatin">isatin</a>) and a second synthesis in 1880 (from <a href="/wiki/2-nitrobenzaldehyde" class="mw-redirect" title="2-nitrobenzaldehyde">2-nitrobenzaldehyde</a>). (It was not until 1883 that Baeyer finally determined the structure of indigo.<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup>) The synthesis of indigo remained impractical, so the search for alternative starting materials at <a href="/wiki/Badische_Anilin-_und_Soda-Fabrik" class="mw-redirect" title="Badische Anilin- und Soda-Fabrik">Badische Anilin- und Soda-Fabrik</a> (BASF) and Hoechst continued. Johannes Pfleger<sup id="cite_ref-history.evonik.com_6-1" class="reference"><a href="#cite_note-history.evonik.com-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> and <a href="https://de.wikipedia.org/wiki/Karl_Heumann" class="extiw" title="de:Karl Heumann">Karl Heumann</a> eventually came up with industrial mass production synthesis.<sup id="cite_ref-ingenious.org.uk_7-1" class="reference"><a href="#cite_note-ingenious.org.uk-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p><p>The synthesis of N-(2-carboxyphenyl)glycine from the easy to obtain <a href="/wiki/Aniline" title="Aniline">aniline</a> provided a new and economically attractive route. BASF developed a commercially feasible manufacturing process that was in use by 1897, at which time 19,000 tons of indigo were being produced from plant sources. This had dropped to 1,000 tons by 1914 and continued to contract. By 2011, 50,000 tons of synthetic indigo were being produced worldwide.<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Dyeing_technology">Dyeing technology</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=7" title="Edit section: Dyeing technology"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Leucoindigo.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/67/Leucoindigo.svg/220px-Leucoindigo.svg.png" decoding="async" width="220" height="120" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/67/Leucoindigo.svg/330px-Leucoindigo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/67/Leucoindigo.svg/440px-Leucoindigo.svg.png 2x" data-file-width="559" data-file-height="306" /></a><figcaption>Indigo white (leuco-indigo)</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:IndigoDyedYarn.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a6/IndigoDyedYarn.JPG/220px-IndigoDyedYarn.JPG" decoding="async" width="220" height="400" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a6/IndigoDyedYarn.JPG/330px-IndigoDyedYarn.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a6/IndigoDyedYarn.JPG/440px-IndigoDyedYarn.JPG 2x" data-file-width="895" data-file-height="1626" /></a><figcaption>Yarn dyed with indigo dye</figcaption></figure> <div class="mw-heading mw-heading3"><h3 id="Indigo_white">Indigo white</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=8" title="Edit section: Indigo white"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Indigo is a challenging dye because it is not <a href="/wiki/Soluble" class="mw-redirect" title="Soluble">soluble</a> in water. To be dissolved, it must undergo a chemical change (<a href="/wiki/Redox" title="Redox">reduction</a>). Reduction converts indigo into "white indigo" (<a href="/wiki/Leuco_dye" title="Leuco dye">leuco</a>-indigo). When a submerged fabric is removed from the dyebath, the white indigo quickly combines with <a href="/wiki/Oxygen" title="Oxygen">oxygen</a> in the air and reverts to the insoluble, intensely colored indigo. When it first became widely available in Europe in the 16th century, European dyers and printers struggled with indigo because of this distinctive property. It also required several chemical manipulations, some involving toxic materials, and presented many opportunities to injure workers. In the 19th century, English poet <a href="/wiki/William_Wordsworth" title="William Wordsworth">William Wordsworth</a> referred to the plight of indigo dye workers of his hometown of Cockermouth in his autobiographical poem <i>The Prelude</i>. Speaking of their dire working conditions and the empathy that he felt for them, he wrote: </p> <style data-mw-deduplicate="TemplateStyles:r1244412712">.mw-parser-output .templatequote{overflow:hidden;margin:1em 0;padding:0 32px}.mw-parser-output .templatequotecite{line-height:1.5em;text-align:left;margin-top:0}@media(min-width:500px){.mw-parser-output .templatequotecite{padding-left:1.6em}}</style><blockquote class="templatequote"><div class="poem"> <p>Doubtless, I should have then made common cause<br /> With some who perished; haply perished too<br /> A poor mistaken and bewildered offering<br /> Unknown to those bare souls of miller blue </p> </div></blockquote> <p>A pre-industrial process for production of indigo white, used in Europe, was to dissolve the indigo in stale urine, which contains ammonia. A more convenient reductive agent is zinc. Another pre-industrial method, used in Japan, was to dissolve the indigo in a heated vat in which a culture of <a href="/wiki/Thermophile" title="Thermophile">thermophilic</a>, <a href="/wiki/Anaerobic_digestion" title="Anaerobic digestion">anaerobic</a> bacteria was maintained. Some species of such bacteria generate <a href="/wiki/Hydrogen" title="Hydrogen">hydrogen</a> as a metabolic product, which convert insoluble indigo into soluble indigo white. Cloth dyed in such a vat was decorated with the techniques of <i><a href="/wiki/Shibori" title="Shibori">shibori</a></i> (<a href="/wiki/Tie-dye" title="Tie-dye">tie-dye</a>), <i><a href="/wiki/Kasuri" title="Kasuri">kasuri</a></i>, <i><a href="/wiki/Katazome" title="Katazome">katazome</a></i>, and <i><a href="/wiki/Tsutsugaki" title="Tsutsugaki">tsutsugaki</a></i>. Examples of clothing and banners dyed with these techniques can be seen in the works of <a href="/wiki/Hokusai" title="Hokusai">Hokusai</a> and other artists. </p> <div class="mw-heading mw-heading3"><h3 id="Direct_printing">Direct printing</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=9" title="Edit section: Direct printing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Two different methods for the direct application of indigo were developed in England in the 18th century and remained in use well into the 19th century. The first method, known as 'pencil blue' because it was most often applied by pencil or brush, could be used to achieve dark hues. <a href="/wiki/Arsenic_trisulfide" title="Arsenic trisulfide">Arsenic trisulfide</a> and a thickener were added to the indigo vat. The arsenic compound delayed the oxidation of the indigo long enough to paint the dye onto fabrics.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (May 2024)">citation needed</span></a></i>]</sup> </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:IndigoDyePotOnStove.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2f/IndigoDyePotOnStove.JPG/220px-IndigoDyePotOnStove.JPG" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2f/IndigoDyePotOnStove.JPG/330px-IndigoDyePotOnStove.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2f/IndigoDyePotOnStove.JPG/440px-IndigoDyePotOnStove.JPG 2x" data-file-width="2288" data-file-height="1712" /></a><figcaption>Pot of freeze-dried indigo dye</figcaption></figure> <p>The second method was known as 'China blue' due to its resemblance to Chinese blue-and-white porcelain. Instead of using an indigo solution directly, the process involved printing the insoluble form of indigo onto the fabric. The indigo was then reduced in a sequence of baths of <a href="/wiki/Iron(II)_sulfate" title="Iron(II) sulfate">iron(II) sulfate</a>, with air oxidation between each immersion. The China blue process could make sharp designs, but it could not produce the dark hues possible with the pencil blue method. </p><p>Around 1880, the 'glucose process' was developed. It finally enabled the direct printing of indigo onto fabric and could produce inexpensive dark indigo prints unattainable with the China blue method. </p><p>Since 2004, <a href="/wiki/Freeze_drying" title="Freeze drying">freeze-dried</a> indigo, or instant indigo, has become available. In this method, the indigo has already been reduced, and then freeze-dried into a crystal. The crystals are added to warm water to create the dye pot. As in a standard indigo dye pot, care has to be taken to avoid mixing in oxygen. Freeze-dried indigo is simple to use, and the crystals can be stored indefinitely as long as they are not exposed to moisture.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Chemical_properties">Chemical properties</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=10" title="Edit section: Chemical properties"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:Indigo3D.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Indigo3D.png/170px-Indigo3D.png" decoding="async" width="170" height="170" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Indigo3D.png/255px-Indigo3D.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Indigo3D.png/340px-Indigo3D.png 2x" data-file-width="1024" data-file-height="1024" /></a><figcaption>Indigo, space-filling</figcaption></figure> <p>Indigo dye is a dark blue crystalline powder that <a href="/wiki/Sublimation_(chemistry)" class="mw-redirect" title="Sublimation (chemistry)">sublimes</a> at 390–392 °C (734–738 °F). It is insoluble in water, <a href="/wiki/Ethanol" title="Ethanol">alcohol</a>, or <a href="/wiki/Diethyl_ether" title="Diethyl ether">ether</a>, but soluble in <a href="/wiki/Dimethyl_sulfoxide" title="Dimethyl sulfoxide">DMSO</a>, <a href="/wiki/Chloroform" title="Chloroform">chloroform</a>, <a href="/wiki/Nitrobenzene" title="Nitrobenzene">nitrobenzene</a>, and concentrated <a href="/wiki/Sulfuric_acid" title="Sulfuric acid">sulfuric acid</a>. The <a href="/wiki/Chemical_formula" title="Chemical formula">chemical formula</a> of indigo is <a href="/wiki/Carbon" title="Carbon">C</a><sub>16</sub><a href="/wiki/Hydrogen" title="Hydrogen">H</a><sub>10</sub><a href="/wiki/Nitrogen" title="Nitrogen">N</a><sub>2</sub><a href="/wiki/Oxygen" title="Oxygen">O</a><sub>2</sub>. </p><p>The molecule absorbs light in the orange part of the spectrum (<i>λ</i><sub>max</sub>=613 nm).<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> The compound owes its deep color to the conjugation of the <a href="/wiki/Double_bond" title="Double bond">double bonds</a>, i.e. the double bonds within the molecule are adjacent and the molecule is planar. In indigo white, the conjugation is interrupted because the molecule is non-planar. </p> <div class="mw-heading mw-heading3"><h3 id="Indigo_derivatives">Indigo derivatives</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=11" title="Edit section: Indigo derivatives"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:Tyrian-Purple.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/1/14/Tyrian-Purple.svg/200px-Tyrian-Purple.svg.png" decoding="async" width="200" height="84" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/14/Tyrian-Purple.svg/300px-Tyrian-Purple.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/14/Tyrian-Purple.svg/400px-Tyrian-Purple.svg.png 2x" data-file-width="667" data-file-height="281" /></a><figcaption>Structure of Tyrian purple</figcaption></figure> <figure typeof="mw:File/Thumb"><a href="/wiki/File:Indigo_carmine.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4d/Indigo_carmine.svg/230px-Indigo_carmine.svg.png" decoding="async" width="230" height="84" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4d/Indigo_carmine.svg/345px-Indigo_carmine.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4d/Indigo_carmine.svg/460px-Indigo_carmine.svg.png 2x" data-file-width="620" data-file-height="227" /></a><figcaption>Structure of indigo carmine.</figcaption></figure> <p>The benzene rings in indigo can be modified to give a variety of related dyestuffs. <a href="/wiki/Thioindigo" title="Thioindigo">Thioindigo</a>, where the two NH groups are replaced by S atoms, is deep red. <a href="/wiki/Tyrian_purple" title="Tyrian purple">Tyrian purple</a> is a dull purple dye that is secreted by a common Mediterranean snail. It was highly prized in antiquity. In 1909, its structure was shown to be <a href="/wiki/6,6%27-dibromoindigo" class="mw-redirect" title="6,6'-dibromoindigo">6,6'-dibromoindigo</a> (red). 6-bromoindigo (purple) is a component as well.<sup id="cite_ref-indigo-bromo_32-0" class="reference"><a href="#cite_note-indigo-bromo-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> It has never been produced on a commercial basis. The related <a href="/w/index.php?title=Ciba_blue&action=edit&redlink=1" class="new" title="Ciba blue (page does not exist)">Ciba blue</a> (5,7,5',7'-tetrabromoindigo) is, however, of commercial value. </p><p>Indigo and its derivatives featuring intra- and intermolecular hydrogen bonding have very low solubility in organic solvents. They can be made soluble using transient <a href="/wiki/Protecting_group" title="Protecting group">protecting groups</a> such as the <a href="/wiki/Tert-butyloxycarbonyl_protecting_group" class="mw-redirect" title="Tert-butyloxycarbonyl protecting group">tBOC group</a>, which suppresses intermolecular bonding.<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> Heating of the tBOC indigo results in efficient thermal deprotection and regeneration of the parent H-bonded pigment. </p><p>Treatment with sulfuric acid converts indigo into a blue-green derivative called <a href="/wiki/Indigo_carmine" title="Indigo carmine">indigo carmine</a> (sulfonated indigo). It became available in the mid-18th century. It is used as a colorant for food, pharmaceuticals, and cosmetics. </p> <div class="mw-heading mw-heading2"><h2 id="Indigo_as_an_organic_semiconductor">Indigo as an organic semiconductor</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=12" title="Edit section: Indigo as an organic semiconductor"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Indigo and some of its derivatives are known to be ambipolar <a href="/wiki/Organic_semiconductors" class="mw-redirect" title="Organic semiconductors">organic semiconductors</a> when deposited as thin films by vacuum evaporation.<sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Safety_and_the_environment">Safety and the environment</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=13" title="Edit section: Safety and the environment"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Indigo has a low oral toxicity, with an <a href="/wiki/Median_lethal_dose" title="Median lethal dose">LD<sub style="font-size:-1">50</sub></a> of 5 g/kg (0.5% of total mass) in mammals.<sup id="cite_ref-Ullmann_1-4" class="reference"><a href="#cite_note-Ullmann-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> In 2009, large spills of blue dyes had been reported downstream of a blue jeans manufacturer in <a href="/wiki/Lesotho" title="Lesotho">Lesotho</a>.<sup id="cite_ref-st2009_35-0" class="reference"><a href="#cite_note-st2009-35"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup> </p><p>The compound has been found to act as an <a href="/wiki/Agonist" title="Agonist">agonist</a> of the <a href="/wiki/Aryl_hydrocarbon_receptor" title="Aryl hydrocarbon receptor">aryl hydrocarbon receptor</a>.<sup id="cite_ref-pmid12540743_36-0" class="reference"><a href="#cite_note-pmid12540743-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=14" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Champaran_Satyagraha" title="Champaran Satyagraha">Champaran Satyagraha</a></li> <li><a href="/wiki/Haint_blue" title="Haint blue">Haint blue</a></li> <li><a href="/wiki/Indigo_revolt" title="Indigo revolt">Indigo revolt</a></li> <li><i><a href="/wiki/Red,_White,_and_Black_Make_Blue" title="Red, White, and Black Make Blue">Red, White, and Black Make Blue</a></i></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=15" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-Ullmann-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-Ullmann_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Ullmann_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Ullmann_1-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-Ullmann_1-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-Ullmann_1-4"><sup><i><b>e</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFSteingruber2004" 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London.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+Manual+of+the+Chemistry+of+the+Carbon+compounds%3B+or%2C+Organic+Chemistry&rft.place=London&rft.date=1874&rft.aulast=Schorlemmer&rft.aufirst=Carl&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Famanualchemistr02schogoog&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span><span class="cs1-maint citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_book" title="Template:Cite book">cite book</a>}}</code>: CS1 maint: location missing publisher (<a href="/wiki/Category:CS1_maint:_location_missing_publisher" title="Category:CS1 maint: location missing publisher">link</a>)</span> Quoted in the <a href="/wiki/Oxford_English_Dictionary" title="Oxford English Dictionary">Oxford English Dictionary</a>, second edition, 1989</span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFreemanPeters2000" class="citation book cs1">Freeman, H. 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"A microscale synthesis of indigo: Vat dyeing". <i>Journal of Chemical Education</i>. <b>68</b> (10): A242. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1991JChEd..68..242M">1991JChEd..68..242M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fed068pA242">10.1021/ed068pA242</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Chemical+Education&rft.atitle=A+microscale+synthesis+of+indigo%3A+Vat+dyeing&rft.volume=68&rft.issue=10&rft.pages=A242&rft.date=1991&rft_id=info%3Adoi%2F10.1021%2Fed068pA242&rft_id=info%3Abibcode%2F1991JChEd..68..242M&rft.aulast=McKee&rft.aufirst=James+R.&rft.au=Zanger%2C+Murray&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSplitstoserDillehayWoutersClaro2016" class="citation journal cs1">Splitstoser JC, Dillehay TD, Wouters J, Claro A (2016-09-14). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5023320">"Early pre-Hispanic use of indigo blue in Peru"</a>. <i><a href="/wiki/Science_Advances" title="Science Advances">Science Advances</a></i>. <b>2</b> (9): e1501623. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2016SciA....2E1623S">2016SciA....2E1623S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fsciadv.1501623">10.1126/sciadv.1501623</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5023320">5023320</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/27652337">27652337</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science+Advances&rft.atitle=Early+pre-Hispanic+use+of+indigo+blue+in+Peru&rft.volume=2&rft.issue=9&rft.pages=e1501623&rft.date=2016-09-14&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC5023320%23id-name%3DPMC&rft_id=info%3Apmid%2F27652337&rft_id=info%3Adoi%2F10.1126%2Fsciadv.1501623&rft_id=info%3Abibcode%2F2016SciA....2E1623S&rft.aulast=Splitstoser&rft.aufirst=JC&rft.au=Dillehay%2C+TD&rft.au=Wouters%2C+J&rft.au=Claro%2C+A&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC5023320&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-k&c-10"><span class="mw-cite-backlink">^ <a href="#cite_ref-k&c_10-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-k&c_10-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-k&c_10-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text">Kriger & Connah, page 120</span> </li> <li id="cite_note-StClair-11"><span class="mw-cite-backlink">^ <a href="#cite_ref-StClair_11-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-StClair_11-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSt._Clair2016" class="citation book cs1">St. Clair, Kassia (2016). <i>The Secret Lives of Colour</i>. London: John Murray. p. 189. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9781473630819" title="Special:BookSources/9781473630819"><bdi>9781473630819</bdi></a>. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/936144129">936144129</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Secret+Lives+of+Colour&rft.place=London&rft.pages=189&rft.pub=John+Murray&rft.date=2016&rft_id=info%3Aoclcnum%2F936144129&rft.isbn=9781473630819&rft.aulast=St.+Clair&rft.aufirst=Kassia&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text">Fowler, Walter (6 August 1991). <i>The Formation of Complex Society in Southeastern Mesoamerica</i>. CRC Press.</span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDenisyuk" class="citation web cs1">Denisyuk, Yulia. <a rel="nofollow" class="external text" href="https://www.bbc.com/travel/article/20230420-blaudruck-europes-secret-dyeing-formula">"Europe's secret dyeing formula"</a>. <i>bbc.com</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2023-04-21</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=bbc.com&rft.atitle=Europe%27s+secret+dyeing+formula&rft.aulast=Denisyuk&rft.aufirst=Yulia&rft_id=https%3A%2F%2Fwww.bbc.com%2Ftravel%2Farticle%2F20230420-blaudruck-europes-secret-dyeing-formula&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text">Quoted in <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHentschel2002" class="citation book cs1">Hentschel, Klaus (2002). <i>Mapping the spectrum: techniques of visual representation in research and teaching</i>. Oxford, England: Oxford University Press. p. 28. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-850953-0" title="Special:BookSources/978-0-19-850953-0"><bdi>978-0-19-850953-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Mapping+the+spectrum%3A+techniques+of+visual+representation+in+research+and+teaching&rft.place=Oxford%2C+England&rft.pages=28&rft.pub=Oxford+University+Press&rft.date=2002&rft.isbn=978-0-19-850953-0&rft.aulast=Hentschel&rft.aufirst=Klaus&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.wildcolours.co.uk/html/indigo_history.html">"History of Indigo & Indigo Dyeing"</a>. <i>wildcolours.co.uk</i>. Wild Colours and natural Dyes<span class="reference-accessdate">. Retrieved <span class="nowrap">30 December</span> 2015</span>. <q>Indigo was often referred to as Blue Gold as it was an ideal trading commodity; high value, compact and long lasting</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=wildcolours.co.uk&rft.atitle=History+of+Indigo+%26+Indigo+Dyeing&rft_id=http%3A%2F%2Fwww.wildcolours.co.uk%2Fhtml%2Findigo_history.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text">Kriger, Colleen E. & Connah, Graham (2006). <i>Cloth in West African History</i>. Rowman Altamira. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-7591-0422-0" title="Special:BookSources/0-7591-0422-0">0-7591-0422-0</a>.</span> </li> <li id="cite_note-GearonEamonn-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-GearonEamonn_17-0">^</a></b></span> <span class="reference-text">Gearon, Eamonn, (2011) <i>The Sahara: A Cultural History</i> Oxford University Press, p. 239</span> </li> <li id="cite_note-Ikegami2005-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-Ikegami2005_18-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEiko_Ikegami2005" class="citation book cs1">Eiko Ikegami (28 February 2005). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=KsN81J1s70kC&pg=PA284"><i>Bonds of Civility: Aesthetic Networks and the Political Origins of Japanese Culture</i></a>. Cambridge University Press. p. 284. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-521-60115-3" title="Special:BookSources/978-0-521-60115-3"><bdi>978-0-521-60115-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Bonds+of+Civility%3A+Aesthetic+Networks+and+the+Political+Origins+of+Japanese+Culture&rft.pages=284&rft.pub=Cambridge+University+Press&rft.date=2005-02-28&rft.isbn=978-0-521-60115-3&rft.au=Eiko+Ikegami&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DKsN81J1s70kC%26pg%3DPA284&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-Sagers2018-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-Sagers2018_19-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJohn_H._Sagers2018" class="citation book cs1">John H. Sagers (20 July 2018). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=1-1lDwAAQBAJ&pg=PA27"><i>Confucian Capitalism: Shibusawa Eiichi, Business Ethics, and Economic Development in Meiji Japan</i></a>. Springer. p. 27. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-319-76372-9" title="Special:BookSources/978-3-319-76372-9"><bdi>978-3-319-76372-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Confucian+Capitalism%3A+Shibusawa+Eiichi%2C+Business+Ethics%2C+and+Economic+Development+in+Meiji+Japan&rft.pages=27&rft.pub=Springer&rft.date=2018-07-20&rft.isbn=978-3-319-76372-9&rft.au=John+H.+Sagers&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D1-1lDwAAQBAJ%26pg%3DPA27&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-Wassenaar2011-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-Wassenaar2011_20-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTrudy_M._Wassenaar2011" class="citation book cs1">Trudy M. Wassenaar (3 November 2011). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=YGtR43I93iMC&pg=PA105"><i>Bacteria: The Benign, the Bad, and the Beautiful</i></a>. John Wiley & Sons. p. 105. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-118-14338-4" title="Special:BookSources/978-1-118-14338-4"><bdi>978-1-118-14338-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Bacteria%3A+The+Benign%2C+the+Bad%2C+and+the+Beautiful&rft.pages=105&rft.pub=John+Wiley+%26+Sons&rft.date=2011-11-03&rft.isbn=978-1-118-14338-4&rft.au=Trudy+M.+Wassenaar&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DYGtR43I93iMC%26pg%3DPA105&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEliza_Layne_Martin" class="citation web cs1">Eliza Layne Martin. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20100607061823/http://cwh.ucsc.edu/SocialBiog.Martin.pdf">"Eliza Lucas Pinckney: Indigo in the Atlantic World"</a> <span class="cs1-format">(PDF)</span>. Archived from <a rel="nofollow" class="external text" href="http://cwh.ucsc.edu/SocialBiog.Martin.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2010-06-07<span class="reference-accessdate">. Retrieved <span class="nowrap">2013-08-24</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Eliza+Lucas+Pinckney%3A+Indigo+in+the+Atlantic+World&rft.au=Eliza+Layne+Martin&rft_id=http%3A%2F%2Fcwh.ucsc.edu%2FSocialBiog.Martin.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text">Andrea Feeser, <i>Red, White, and Black Make Blue: Indigo in the Fabric of Colonial South Carolina Life</i> (University of Georgia Press; 2013)</span> </li> <li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJones1958" class="citation journal cs1">Jones, Claude E. (1958). "Charles Woodmason as a Poet". <i>The South Carolina Historical Magazine</i>. <b>59</b> (4): 189–194.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+South+Carolina+Historical+Magazine&rft.atitle=Charles+Woodmason+as+a+Poet&rft.volume=59&rft.issue=4&rft.pages=189-194&rft.date=1958&rft.aulast=Jones&rft.aufirst=Claude+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFShields2010" class="citation book cs1">Shields, David S. (2010). <i>Oracles of Empire: Poetry, Politics, and Commerce in British America, 1690-1750</i>. University of Chicago Press. pp. 69, 249.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Oracles+of+Empire%3A+Poetry%2C+Politics%2C+and+Commerce+in+British+America%2C+1690-1750&rft.pages=69%2C+249&rft.pub=University+of+Chicago+Press&rft.date=2010&rft.aulast=Shields&rft.aufirst=David+S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEdgar2006" class="citation book cs1">Edgar, Walter B., ed. (2006). <i>The South Carolina Encyclopedia</i>. University of South Carolina Press. p. 9.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+South+Carolina+Encyclopedia&rft.pages=9&rft.pub=University+of+South+Carolina+Press&rft.date=2006&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchoenbrun1976" class="citation book cs1">Schoenbrun, David (1976). <i>Triumph in Paris: The Exploits of Benjamin Franklin</i>. New York: Harper & Row. p. 51. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-06-013854-7" title="Special:BookSources/978-0-06-013854-7"><bdi>978-0-06-013854-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Triumph+in+Paris%3A+The+Exploits+of+Benjamin+Franklin&rft.place=New+York&rft.pages=51&rft.pub=Harper+%26+Row&rft.date=1976&rft.isbn=978-0-06-013854-7&rft.aulast=Schoenbrun&rft.aufirst=David&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-27">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDavid_H._Rembert_Jr.1979" class="citation journal cs1">David H. Rembert Jr. (1979). 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"Indigo - A Natural Pigment for High Performance Ambipolar Organic Field Effect Transistors and Circuits". <i>Advanced Materials</i>. <b>24</b> (3): 375–380. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2012AdM....24..375I">2012AdM....24..375I</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fadma.201102619">10.1002/adma.201102619</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/22109816">22109816</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:205241976">205241976</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Advanced+Materials&rft.atitle=Indigo+-+A+Natural+Pigment+for+High+Performance+Ambipolar+Organic+Field+Effect+Transistors+and+Circuits&rft.volume=24&rft.issue=3&rft.pages=375-380&rft.date=2012&rft_id=info%3Adoi%2F10.1002%2Fadma.201102619&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A205241976%23id-name%3DS2CID&rft_id=info%3Apmid%2F22109816&rft_id=info%3Abibcode%2F2012AdM....24..375I&rft.aulast=Irimia-Vladu&rft.aufirst=Mihai&rft.au=G%C5%82owacki%2C+Eric+D.&rft.au=Troshin%2C+Pavel+A.&rft.au=Schwabegger%2C+G%C3%BCnther&rft.au=Leonat%2C+Lucia&rft.au=Susarova%2C+Diana+K.&rft.au=Krystal%2C+Olga&rft.au=Ullah%2C+Mujeeb&rft.au=Kanbur%2C+Yasin&rft.au=Bodea%2C+Marius+A.&rft.au=Razum%2C+Vladimir+F.&rft.au=Sitter%2C+Helmut&rft.au=Bauer%2C+Siegfried&rft.au=Sar%C4%B1%C3%A7ift%C3%A7i%2C+Niyazi+Serdar&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-st2009-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-st2009_35-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://archive.today/20100528081251/http://www.timesonline.co.uk/tol/news/world/africa/article6788728.ece">"Gap alarm"</a>. <i><a href="/wiki/The_Sunday_Times" title="The Sunday Times">The Sunday Times</a></i>. 2009-08-09. Archived from <a rel="nofollow" class="external text" href="http://www.timesonline.co.uk/tol/news/world/africa/article6788728.ece">the original</a> on May 28, 2010<span class="reference-accessdate">. Retrieved <span class="nowrap">2011-08-16</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Sunday+Times&rft.atitle=Gap+alarm&rft.date=2009-08-09&rft_id=http%3A%2F%2Fwww.timesonline.co.uk%2Ftol%2Fnews%2Fworld%2Fafrica%2Farticle6788728.ece&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> <li id="cite_note-pmid12540743-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-pmid12540743_36-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDenisonNagy2003" class="citation journal cs1">Denison MS, Nagy SR (2003). "Activation of the aryl hydrocarbon receptor by structurally diverse exogenous and endogenous chemicals". <i>Annu. Rev. Pharmacol. Toxicol</i>. <b>43</b>: 309–334. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1146%2Fannurev.pharmtox.43.100901.135828">10.1146/annurev.pharmtox.43.100901.135828</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/12540743">12540743</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annu.+Rev.+Pharmacol.+Toxicol.&rft.atitle=Activation+of+the+aryl+hydrocarbon+receptor+by+structurally+diverse+exogenous+and+endogenous+chemicals&rft.volume=43&rft.pages=309-334&rft.date=2003&rft_id=info%3Adoi%2F10.1146%2Fannurev.pharmtox.43.100901.135828&rft_id=info%3Apmid%2F12540743&rft.aulast=Denison&rft.aufirst=MS&rft.au=Nagy%2C+SR&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=16" title="Edit section: Further reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBalfour-Paul2016" class="citation book cs1">Balfour-Paul, Jenny (2016). <i>Indigo: Egyptian Mummies to Blue Jeans</i>. London: British Museum Press. pp. 264 pages. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7141-1776-8" title="Special:BookSources/978-0-7141-1776-8"><bdi>978-0-7141-1776-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Indigo%3A+Egyptian+Mummies+to+Blue+Jeans&rft.place=London&rft.pages=264+pages&rft.pub=British+Museum+Press&rft.date=2016&rft.isbn=978-0-7141-1776-8&rft.aulast=Balfour-Paul&rft.aufirst=Jenny&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFerreiraHulme_A._N.McNab_H.Quye_A.2004" class="citation journal cs1">Ferreira, E.S.B.; <a href="/wiki/Alison_Hulme" title="Alison Hulme">Hulme A. N.</a>; McNab H.; Quye A. (2004). <a rel="nofollow" class="external text" href="http://eprints.gla.ac.uk/109139/1/109148.pdf">"The natural constituents of historical textile dyes"</a> <span class="cs1-format">(PDF)</span>. <i>Chemical Society Reviews</i>. <b>33</b> (6): 329–36. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1039%2Fb305697j">10.1039/b305697j</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/15280965">15280965</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Chemical+Society+Reviews&rft.atitle=The+natural+constituents+of+historical+textile+dyes&rft.volume=33&rft.issue=6&rft.pages=329-36&rft.date=2004&rft_id=info%3Adoi%2F10.1039%2Fb305697j&rft_id=info%3Apmid%2F15280965&rft.aulast=Ferreira&rft.aufirst=E.S.B.&rft.au=Hulme+A.+N.&rft.au=McNab+H.&rft.au=Quye+A.&rft_id=http%3A%2F%2Feprints.gla.ac.uk%2F109139%2F1%2F109148.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></li> <li>Paul, Jenny Balfour. 2020. "Indigo and Blue: A Marriage Made in Heaven." <i>Textile Museum Journal</i> 47 (January): 160–85.</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSequin-Frey1981" class="citation journal cs1">Sequin-Frey, Margareta (1981). <a rel="nofollow" class="external text" href="http://jchemed.chem.wisc.edu/Journal/Issues/1981/Apr/jceSubscriber/JCE1981p0301.pdf">"The chemistry of plant and animal dyes"</a> <span class="cs1-format">(PDF)</span>. <i>Journal of Chemical Education</i>. <b>58</b> (4): 301. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1981JChEd..58..301S">1981JChEd..58..301S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1021%2Fed058p301">10.1021/ed058p301</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Chemical+Education&rft.atitle=The+chemistry+of+plant+and+animal+dyes&rft.volume=58&rft.issue=4&rft.pages=301&rft.date=1981&rft_id=info%3Adoi%2F10.1021%2Fed058p301&rft_id=info%3Abibcode%2F1981JChEd..58..301S&rft.aulast=Sequin-Frey&rft.aufirst=Margareta&rft_id=http%3A%2F%2Fjchemed.chem.wisc.edu%2FJournal%2FIssues%2F1981%2FApr%2FjceSubscriber%2FJCE1981p0301.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AIndigo+dye" class="Z3988"></span></li></ul> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Indigo_dye&action=edit&section=17" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20080509184103/http://www.plantcultures.org/plants/indigo_landing.html">Plant Cultures: botany, history and uses of indigo</a></li> <li><a rel="nofollow" class="external text" href="https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=74.102">FD&C regulation on indigotine</a></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul 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.navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Dyeing" 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template">e</abbr></a></li></ul></div><div id="Dyeing" style="font-size:114%;margin:0 4em"><a href="/wiki/Dyeing" title="Dyeing">Dyeing</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Techniques</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Batik" title="Batik">Batik</a></li> <li><a href="/wiki/Dyeing" title="Dyeing">Dyeing</a></li> <li><a href="/wiki/Ikat" title="Ikat">Ikat</a> <ul><li><span title="Japanese-language romanization"><i lang="ja-Latn"><a href="/wiki/Kasuri" title="Kasuri">Kasuri</a></i></span></li></ul></li> <li><a href="/wiki/Kalamkari" title="Kalamkari">Kalamkari</a></li> <li><span title="Japanese-language romanization"><i lang="ja-Latn"><a href="/wiki/Katazome" title="Katazome">Katazome</a></i></span></li> <li><a href="/wiki/Leheria" class="mw-redirect" title="Leheria">Leheria</a></li> <li><a href="/wiki/Mordant" title="Mordant">Mordant</a></li> <li><a href="/wiki/Reactive_dye_printing" title="Reactive dye printing">Reactive dye printing</a></li> <li><a href="/wiki/Resist_dyeing" title="Resist dyeing">Resist</a></li> <li><a href="/wiki/Ring_dyeing" title="Ring dyeing">Ring dyeing</a></li> <li><span title="Japanese-language romanization"><i lang="ja-Latn"><a href="/wiki/R%C5%8Dketsuzome" title="Rōketsuzome">Rōketsuzome</a></i></span></li> <li><a href="/wiki/Shibori" title="Shibori">Shibori</a></li> <li><a href="/wiki/Tie-dye" title="Tie-dye">Tie-dye</a></li> <li><span title="Japanese-language romanization"><i lang="ja-Latn"><a href="/wiki/Tsutsugaki" title="Tsutsugaki">Tsutsugaki</a></i></span></li> <li><span title="Japanese-language romanization"><i lang="ja-Latn"><a href="/wiki/Y%C5%ABzen" title="Yūzen">Yūzen</a></i></span></li></ul> </div></td><td class="noviewer navbox-image" rowspan="6" style="width:1px;padding:0 0 0 2px"><div><figure class="mw-halign-right" typeof="mw:File"><a href="/wiki/File:Teinture_naturelle_Millepertuis_2.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/91/Teinture_naturelle_Millepertuis_2.jpg/100px-Teinture_naturelle_Millepertuis_2.jpg" decoding="async" width="100" height="133" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/91/Teinture_naturelle_Millepertuis_2.jpg/150px-Teinture_naturelle_Millepertuis_2.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/91/Teinture_naturelle_Millepertuis_2.jpg/200px-Teinture_naturelle_Millepertuis_2.jpg 2x" data-file-width="599" data-file-height="799" /></a><figcaption></figcaption></figure></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Types of dyes</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Dye" title="Dye">Dyes</a></li> <li><a href="/wiki/Natural_dye" title="Natural dye">Natural</a></li> <li><a href="/wiki/Acid_dye" title="Acid dye">Acid</a></li> <li><a href="/wiki/Reactive_dye" title="Reactive dye">Reactive</a></li> <li><a href="/wiki/Solvent_dye" title="Solvent dye">Solvent</a></li> <li><a href="/wiki/Substantive_dye" title="Substantive dye">Substantive</a></li> <li><a href="/wiki/Sulfur_dye" title="Sulfur dye">Sulfur</a></li> <li><a href="/wiki/Vat_dye" title="Vat dye">Vat</a></li> <li><a href="/wiki/Disperse_dye" title="Disperse dye">Disperse</a></li> <li><a href="/wiki/Discharge_printing" title="Discharge printing">Discharge</a></li> <li><a href="/wiki/Pigment" title="Pigment">Pigment</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Traditional textile dyes</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Armenian_cochineal" title="Armenian cochineal">Armenian cochineal</a></li> <li><a href="/wiki/Juglans_nigra" title="Juglans nigra">Black walnut</a></li> <li><a href="/wiki/Sanguinaria" title="Sanguinaria">Bloodroot</a></li> <li><a href="/wiki/Brazilin" title="Brazilin">Brazilin</a></li> <li><a href="/wiki/Cochineal#Dye" title="Cochineal">Cochineal</a></li> <li><a href="/wiki/Orcein" title="Orcein">Cudbear</a></li> <li><a href="/wiki/Catechu" title="Catechu">Cutch</a></li> <li><a href="/wiki/Dyewoods" title="Dyewoods">Dyewoods</a></li> <li><a href="/wiki/Maclura_tinctoria" title="Maclura tinctoria">Fustic</a></li> <li><a href="/wiki/Gamboge" title="Gamboge">Gamboge</a></li> <li><a href="/wiki/Genista_tinctoria" title="Genista tinctoria">Dyer's broom</a></li> <li><a href="/wiki/Henna" title="Henna">Henna</a></li> <li><a class="mw-selflink selflink">Indigo</a></li> <li><a href="/wiki/Kermes_(dye)" title="Kermes (dye)">Kermes</a></li> <li><a href="/wiki/Haematoxylum_campechianum" title="Haematoxylum campechianum">Logwood</a></li> <li><a href="/wiki/Rubia" title="Rubia">Madder</a></li> <li><a href="/wiki/Polish_cochineal" title="Polish cochineal">Polish cochineal</a></li> <li><a href="/wiki/Saffron" title="Saffron">Saffron</a></li> <li><a href="/wiki/Turmeric#Dye" title="Turmeric">Turmeric</a></li> <li><a href="/wiki/Tyrian_purple" title="Tyrian purple">Tyrian purple</a></li> <li><a href="/wiki/Reseda_(plant)" title="Reseda (plant)">Weld</a></li> <li><a href="/wiki/Isatis_tinctoria" title="Isatis tinctoria">Woad</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">History</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Trade_and_use_of_saffron" class="mw-redirect" title="Trade and use of saffron">Use of saffron</a></li> <li><a href="/wiki/Traditional_dyes_of_the_Scottish_Highlands" title="Traditional dyes of the Scottish Highlands">Traditional dyes of the Scottish Highlands</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Craft dyes</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Dylon" title="Dylon">Dylon</a></li> <li><a href="/wiki/Lumi_(company)" title="Lumi (company)">Inkodye</a></li> <li><a href="/wiki/Procion" title="Procion">Procion</a></li> <li><a href="/wiki/Rit_(dye)" title="Rit (dye)">Rit</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Reference</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Glossary_of_dyeing_terms" title="Glossary of dyeing terms">Glossary of dyeing terms</a></li> <li><a href="/wiki/List_of_dyes" title="List of dyes">List of dyes</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Aryl_hydrocarbon_receptor_modulators" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Aryl_hydrocarbon_receptor_modulators" title="Template:Aryl hydrocarbon receptor modulators"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Aryl_hydrocarbon_receptor_modulators" title="Template talk:Aryl hydrocarbon receptor modulators"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Aryl_hydrocarbon_receptor_modulators" title="Special:EditPage/Template:Aryl hydrocarbon receptor modulators"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Aryl_hydrocarbon_receptor_modulators" style="font-size:114%;margin:0 4em"><a href="/wiki/Aryl_hydrocarbon_receptor" title="Aryl hydrocarbon receptor">Aryl hydrocarbon receptor</a> <a href="/wiki/Receptor_modulator" title="Receptor modulator">modulators</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;"><a href="/wiki/Aryl_hydrocarbon_receptor" title="Aryl hydrocarbon receptor"><abbr title="Aryl hydrocarbon receptor">AhR</abbr></a><span class="sr-only" style="border: 0; clip: rect(0, 0, 0, 0); clip-path: polygon(0px 0px, 0px 0px, 0px 0px); height: 1px; margin: -1px; overflow: hidden; padding: 0; position: absolute; width: 1px; white-space: nowrap;">Tooltip Aryl hydrocarbon receptor</span></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><i>Agonists:</i> <a href="/wiki/Arachidonic_acid" title="Arachidonic acid">Arachidonic acid</a> <a href="/wiki/Metabolite" title="Metabolite">metabolites</a> (e.g., <a href="/wiki/Lipoxin_A4" class="mw-redirect" title="Lipoxin A4">lipoxin A4</a>, <a href="/wiki/Prostaglandin_G2" title="Prostaglandin G2">prostaglandin G2</a>)</li> <li><a href="/wiki/Carotenoid" title="Carotenoid">Dietary carotenoids</a></li> <li><a href="/wiki/Flutamide" title="Flutamide">Flutamide</a></li> <li><a href="/wiki/Halogen" title="Halogen">Halogenated</a> <a href="/wiki/Aromatic_hydrocarbon" class="mw-redirect" title="Aromatic hydrocarbon">aromatic hydrocarbons</a> (e.g., <a href="/wiki/Polychlorinated_dibenzodioxin" class="mw-redirect" title="Polychlorinated dibenzodioxin">polychlorinated dibenzodioxins</a> (e.g., <a href="/wiki/2,3,7,8-Tetrachlorodibenzodioxin" title="2,3,7,8-Tetrachlorodibenzodioxin">TCDD</a>), <a href="/wiki/Dibenzofuran" title="Dibenzofuran">dibenzofurans</a>, <a href="/wiki/Biphenyl" title="Biphenyl">biphenyls</a>)</li> <li><a href="/w/index.php?title=2-(1H-Indol-3-ylcarbonyl)-4-thiazolecarboxylic_acid_methyl_ester&action=edit&redlink=1" class="new" title="2-(1H-Indol-3-ylcarbonyl)-4-thiazolecarboxylic acid methyl ester (page does not exist)">ΙΤΕ</a></li> <li><a href="/wiki/Low-density_lipoprotein" title="Low-density lipoprotein">Modified low-density lipoproteins</a></li> <li><a href="/wiki/Polycyclic_aromatic_hydrocarbon" title="Polycyclic aromatic hydrocarbon">Polycyclic aromatic hydrocarbons</a> (e.g., <a href="/wiki/3-methylcholanthrene" class="mw-redirect" title="3-methylcholanthrene">3-methylcholanthrene</a>, <a href="/wiki/Benzo(a)pyrene" title="Benzo(a)pyrene">benzo[a]pyrene</a>, <a href="/wiki/Benzanthracene" class="mw-redirect" title="Benzanthracene">benzanthracenes</a>, <a href="/wiki/Benzoflavone" class="mw-redirect" title="Benzoflavone">benzoflavones</a> (e.g., <a href="/wiki/%CE%92-naphthoflavone" class="mw-redirect" title="Β-naphthoflavone">β-naphthoflavone</a>))</li> <li><a href="/wiki/Tapinarof" title="Tapinarof">Tapinarof (benvitimod)</a></li> <li><a href="/wiki/Tetrapyrole" class="mw-redirect" title="Tetrapyrole">Tetrapyroles</a> (e.g., <a href="/wiki/Bilirubin" title="Bilirubin">bilirubin</a>)</li> <li><a href="/wiki/Tryptophan" title="Tryptophan">Tryptophan</a> <a href="/wiki/Chemical_derivative" class="mw-redirect" title="Chemical derivative">derivatives</a> (e.g., <a class="mw-selflink selflink">indigo dye</a>, <a href="/wiki/Indirubin" title="Indirubin">indirubin</a>)</li></ul> <ul><li><i>Antagonists:</i> <a href="/w/index.php?title=7-Ketocholesterol&action=edit&redlink=1" class="new" title="7-Ketocholesterol (page does not exist)">7-Ketocholesterol</a></li> <li><a href="/w/index.php?title=CH-223191&action=edit&redlink=1" class="new" title="CH-223191 (page does not exist)">CH-223191</a></li> <li><a href="/wiki/Cyproterone_acetate" title="Cyproterone acetate">Cyproterone acetate</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <dl><dt>See also</dt> <dd><i><a href="/wiki/Template:Receptor_modulators" title="Template:Receptor modulators">Receptor/signaling modulators</a></i></dd></dl> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><style data-mw-deduplicate="TemplateStyles:r1038841319">.mw-parser-output .tooltip-dotted{border-bottom:1px dotted;cursor:help}</style><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1038841319"><link rel="mw-deduplicated-inline-style" 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