<span class="mw-page-title-main">Blue</span>

Blue

<p><b>Blue</b> is one of the three <a href="/en/Primary_colours" title="Primary colours" class="mw-redirect wl">primary colours</a> in the <a href="/en/RYB_color_model" title="RYB color model" class="wl">RYB colour model</a> (traditional colour theory), as well as in the <a href="/en/RGB_color_model" title="RGB color model" class="wl">RGB (additive) colour model</a>.<span class="mw-ref reference" id="cite_ref-2"><a href="#cite_note-2" style="counter-reset: mw-Ref 2;"><span class="mw-reflink-text">[2]</span></a></span> It lies between <a href="/en/Violet_(color)" title="Violet (color)" class="wl">violet</a> and <a href="/en/Cyan" title="Cyan" class="wl">cyan</a> on the <a href="/en/Optical_spectrum" title="Optical spectrum" class="mw-redirect wl">spectrum</a> of <a href="/en/Visible_light" title="Visible light" class="mw-redirect wl">visible light</a>. The eye perceives blue when observing light with a <a href="/en/Dominant_wavelength" title="Dominant wavelength" class="wl">dominant wavelength</a> between approximately 450 and 495 <a href="/en/Nanometre" title="Nanometre" class="wl">nanometres</a>. Most blues contain a slight mixture of other colours; <a href="/en/Azure_(color)" title="Azure (color)" class="wl">azure</a> contains some green, while <a href="/en/Ultramarine" title="Ultramarine" class="wl">ultramarine</a> contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as <a href="/en/Rayleigh_scattering#Cause_of_the_blue_colour_of_the_sky" title="Rayleigh scattering" class="wl">Rayleigh scattering</a>. An optical effect called <a href="/en/Tyndall_effect" title="Tyndall effect" class="wl">Tyndall effect</a> explains <a href="/en/Eye_color#Blue" title="Eye color" class="wl">blue eyes</a>. Distant objects appear more blue because of another optical effect called <a href="/en/Aerial_perspective" title="Aerial perspective" class="wl">aerial perspective</a>.</p>

<div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none" about="#mwt1">Primary colour between purple and green</div>
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<style data-mw-deduplicate="TemplateStyles:r1066479718" typeof="mw:Extension/templatestyles mw:Transclusion">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}body.skin-minerva .mw-parser-output .infobox-header,body.skin-minerva .mw-parser-output .infobox-subheader,body.skin-minerva .mw-parser-output .infobox-above,body.skin-minerva .mw-parser-output .infobox-title,body.skin-minerva .mw-parser-output .infobox-image,body.skin-minerva .mw-parser-output .infobox-full-data,body.skin-minerva .mw-parser-output .infobox-below{text-align:center}</style><div class='mobile-collapse'><header class="mobile-collapse-header mobile-collapse-btn"><b>Quick facts: Blue, Spectral coordinates, Wavelength, Frequ...</b> <span class='arrow'>▼</span></header> <table class="infobox mobile-collapse-element"><tbody><tr><th colspan="2" class="infobox-above">Blue</th></tr><tr><td colspan="2" class="infobox-subheader notheme" style="line-height:12px; background-color:#0000FF; border: 0.1px solid #000000"><span>&nbsp;</span></td></tr><tr><td colspan="2" class="infobox-image"><div style="background-color:#F9F9F9;border-collapse:collapse;border:1px solid #AAAAAA;width:243px;display:table;margin-left: auto; margin-right: auto;" class="notheme"><div style="display:table-row"><div style="display:table-cell;border-top:0;padding:1px 0 0 1px"><div style="display:table;background-color:#F9F9F9;border-collapse:collapse" class="notheme"><div style="display:table-row"><div style="display:table-cell;border-top:0;padding:0 1px 1px 0"><span><a href="/en/File:2010._Донецк._Карнавал_на_день_города_010.jpg" class="mw-file-description image media-thumb" data-hash="File:2010._Донецк._Карнавал_на_день_города_010.jpg"><img loading="lazy" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1a/2010._%D0%94%D0%BE%D0%BD%D0%B5%D1%86%D0%BA._%D0%9A%D0%B0%D1%80%D0%BD%D0%B0%D0%B2%D0%B0%D0%BB_%D0%BD%D0%B0_%D0%B4%D0%B5%D0%BD%D1%8C_%D0%B3%D0%BE%D1%80%D0%BE%D0%B4%D0%B0_010.jpg/80px-2010._%D0%94%D0%BE%D0%BD%D0%B5%D1%86%D0%BA._%D0%9A%D0%B0%D1%80%D0%BD%D0%B0%D0%B2%D0%B0%D0%BB_%D0%BD%D0%B0_%D0%B4%D0%B5%D0%BD%D1%8C_%D0%B3%D0%BE%D1%80%D0%BE%D0%B4%D0%B0_010.jpg" decoding="async" data-file-width="1536" data-file-height="2048" data-file-type="bitmap" height="107" width="80" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1a/2010._%D0%94%D0%BE%D0%BD%D0%B5%D1%86%D0%BA._%D0%9A%D0%B0%D1%80%D0%BD%D0%B0%D0%B2%D0%B0%D0%BB_%D0%BD%D0%B0_%D0%B4%D0%B5%D0%BD%D1%8C_%D0%B3%D0%BE%D1%80%D0%BE%D0%B4%D0%B0_010.jpg/120px-2010._%D0%94%D0%BE%D0%BD%D0%B5%D1%86%D0%BA._%D0%9A%D0%B0%D1%80%D0%BD%D0%B0%D0%B2%D0%B0%D0%BB_%D0%BD%D0%B0_%D0%B4%D0%B5%D0%BD%D1%8C_%D0%B3%D0%BE%D1%80%D0%BE%D0%B4%D0%B0_010.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1a/2010._%D0%94%D0%BE%D0%BD%D0%B5%D1%86%D0%BA._%D0%9A%D0%B0%D1%80%D0%BD%D0%B0%D0%B2%D0%B0%D0%BB_%D0%BD%D0%B0_%D0%B4%D0%B5%D0%BD%D1%8C_%D0%B3%D0%BE%D1%80%D0%BE%D0%B4%D0%B0_010.jpg/160px-2010._%D0%94%D0%BE%D0%BD%D0%B5%D1%86%D0%BA._%D0%9A%D0%B0%D1%80%D0%BD%D0%B0%D0%B2%D0%B0%D0%BB_%D0%BD%D0%B0_%D0%B4%D0%B5%D0%BD%D1%8C_%D0%B3%D0%BE%D1%80%D0%BE%D0%B4%D0%B0_010.jpg 2x" alt="2010._%D0%94%D0%BE%D0%BD%D0%B5%D1%86%D0%BA._%D0%9A%D0%B0%D1%80%D0%BD%D0%B0%D0%B2%D0%B0%D0%BB_%D0%BD%D0%B0_%D0%B4%D0%B5%D0%BD%D1%8C_%D0%B3%D0%BE%D1%80%D0%BE%D0%B4%D0%B0_010.jpg"></a></span></div><div style="display:table-cell;border-top:0;padding:0 1px 1px 0"><span><a href="/en/File:Iranian_Tiles_1.JPG" class="mw-file-description image media-thumb" data-hash="File:Iranian_Tiles_1.JPG"><img loading="lazy" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/40/Iranian_Tiles_1.JPG/80px-Iranian_Tiles_1.JPG" decoding="async" data-file-width="2511" data-file-height="3648" data-file-type="bitmap" height="116" width="80" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/40/Iranian_Tiles_1.JPG/120px-Iranian_Tiles_1.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/40/Iranian_Tiles_1.JPG/160px-Iranian_Tiles_1.JPG 2x" alt="Iranian_Tiles_1.JPG"></a></span></div><div style="display:table-cell;border-top:0;padding:0 1px 1px 0"><span><a href="/en/File:Cyanerpes_cyaneus_-Diergaarde_Blijdorp,_Netherlands-8a.jpg" class="mw-file-description image media-thumb" data-hash="File:Cyanerpes_cyaneus_-Diergaarde_Blijdorp,_Netherlands-8a.jpg"><img loading="lazy" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Cyanerpes_cyaneus_-Diergaarde_Blijdorp%2C_Netherlands-8a.jpg/80px-Cyanerpes_cyaneus_-Diergaarde_Blijdorp%2C_Netherlands-8a.jpg" decoding="async" data-file-width="2779" data-file-height="4168" data-file-type="bitmap" height="120" width="80" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Cyanerpes_cyaneus_-Diergaarde_Blijdorp%2C_Netherlands-8a.jpg/120px-Cyanerpes_cyaneus_-Diergaarde_Blijdorp%2C_Netherlands-8a.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Cyanerpes_cyaneus_-Diergaarde_Blijdorp%2C_Netherlands-8a.jpg/160px-Cyanerpes_cyaneus_-Diergaarde_Blijdorp%2C_Netherlands-8a.jpg 2x" alt="Cyanerpes_cyaneus_-Diergaarde_Blijdorp%2C_Netherlands-8a.jpg"></a></span></div></div></div><div style="display:table;background-color:#F9F9F9;border-collapse:collapse" class="notheme"><div style="display:table-row"><div style="display:table-cell;border-top:0;padding:0 1px 1px 0"><span><a href="/en/File:NASA_Earth_America_2010.jpg" class="mw-file-description image media-thumb" data-hash="File:NASA_Earth_America_2010.jpg"><img loading="lazy" src="//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/NASA_Earth_America_2002.jpg/121px-NASA_Earth_America_2002.jpg" decoding="async" data-file-width="2048" data-file-height="2048" data-file-type="bitmap" height="121" width="121" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/NASA_Earth_America_2002.jpg/182px-NASA_Earth_America_2002.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/aa/NASA_Earth_America_2002.jpg/242px-NASA_Earth_America_2002.jpg 2x" alt="NASA_Earth_America_2002.jpg"></a></span></div><div style="display:table-cell;border-top:0;padding:0 1px 1px 0"><span><a href="/en/File:Copper_sulfate.jpg" class="mw-file-description image media-thumb" data-hash="File:Copper_sulfate.jpg"><img loading="lazy" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Copper_sulfate.jpg/121px-Copper_sulfate.jpg" decoding="async" data-file-width="900" data-file-height="922" data-file-type="bitmap" height="124" width="121" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Copper_sulfate.jpg/182px-Copper_sulfate.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Copper_sulfate.jpg/242px-Copper_sulfate.jpg 2x" alt="Copper_sulfate.jpg"></a></span></div></div></div><div style="display:table;background-color:#F9F9F9;border-collapse:collapse" class="notheme"><div style="display:table-row"><div style="display:table-cell;border-top:0;padding:0 1px 1px 0"><span><a href="/en/File:The_deep_blue_sea_(6834127561).jpg" class="mw-file-description image media-thumb" data-hash="File:The_deep_blue_sea_(6834127561).jpg"><img loading="lazy" src="//upload.wikimedia.org/wikipedia/commons/thumb/7/7e/The_deep_blue_sea_%286834127561%29.jpg/243px-The_deep_blue_sea_%286834127561%29.jpg" decoding="async" data-file-width="1280" data-file-height="530" data-file-type="bitmap" height="101" width="243" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/7e/The_deep_blue_sea_%286834127561%29.jpg/365px-The_deep_blue_sea_%286834127561%29.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/7e/The_deep_blue_sea_%286834127561%29.jpg/486px-The_deep_blue_sea_%286834127561%29.jpg 2x" alt="The_deep_blue_sea_%286834127561%29.jpg"></a></span></div></div></div></div></div></div><div class="infobox-caption">Clockwise, from top left: Police officer on duty; Tiles of the <a href="/en/Sheikh_Lotfollah_Mosque" title="Sheikh Lotfollah Mosque" class="wl">Sheikh Lotfollah Mosque</a>, Iran; <a href="/en/Red-legged_honeycreeper" title="Red-legged honeycreeper" class="wl">Red-legged honeycreeper</a>; <a href="/en/Copper(II)_sulfate" title="Copper(II) sulfate" class="wl">Copper(II) sulfate</a>; Sea at the <a href="/en/Marshall_Islands" title="Marshall Islands" class="wl">Marshall Islands</a>; <a href="/en/Planet_Earth" title="Planet Earth" class="mw-redirect wl">Planet Earth</a>.</div></td></tr><tr><th colspan="2" class="infobox-header"><a href="/en/Spectral_color" title="Spectral color" class="wl">Spectral coordinates</a></th></tr><tr><th scope="row" class="infobox-label"><a href="/en/Wavelength" title="Wavelength" class="wl">Wavelength</a></th><td class="infobox-data">approx. 450–495 <a href="/en/Nanometre" title="Nanometre" class="wl">nm</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/en/Frequency" title="Frequency" class="wl">Frequency</a></th><td class="infobox-data">~670–610 <a href="/en/Terahertz_(unit)" title="Terahertz (unit)" class="mw-redirect wl">THz</a></td></tr><tr><th colspan="2" class="infobox-header"><span style="position: relative; float: right; font-size: 70%"><span><a href="/en/Wikipedia:WikiProject_Color/Normalized_Color_Coordinates" title="About these coordinates" class="image wl"><img loading="lazy"alt="About these coordinates" src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Gtk-dialog-info.svg/15px-Gtk-dialog-info.svg.png" decoding="async" data-file-width="60" data-file-height="60" data-file-type="drawing" height="15" width="15" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Gtk-dialog-info.svg/23px-Gtk-dialog-info.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Gtk-dialog-info.svg/30px-Gtk-dialog-info.svg.png 2x"></a></span></span> <span>&nbsp;</span> <span>&nbsp;</span> Colour coordinates</th></tr><tr><th scope="row" class="infobox-label"><a href="/en/Web_colors#Hex_triplet" title="Web colors" class="wl">Hex triplet</a></th><td class="infobox-data"><span>#</span>0000FF</td></tr><tr><th scope="row" class="infobox-label"><span class="nowrap"><a href="/en/SRGB" title="SRGB" class="wl">sRGB</a><sup><b>B</b></sup> (<a href="/en/Red" title="Red" class="wl">r</a>, <a href="/en/Green" title="Green" class="wl">g</a>, <a href="/en/Blue" title="Blue" class="wl">b</a>)</span></th><td class="infobox-data"><span class="nowrap">(0, 0, 255)</span></td></tr><tr><th scope="row" class="infobox-label"><span class="nowrap"><a href="/en/CMYK_color_model" title="CMYK color model" class="wl">CMYK</a><sup><b>H</b></sup> (<a href="/en/Cyan" title="Cyan" class="wl">c</a>, <a href="/en/Magenta" title="Magenta" class="wl">m</a>, <a href="/en/Yellow" title="Yellow" class="wl">y</a>, <a href="/en/Black" title="Black" class="wl">k</a>)</span></th><td class="infobox-data"><span class="nowrap">(100, 100, 0, 0)</span></td></tr><tr><th scope="row" class="infobox-label"><span class="nowrap"><a href="/en/HSL_and_HSV" title="HSL and HSV" class="wl">HSV</a> (<a href="/en/Hue" title="Hue" class="wl">h</a>, <a href="/en/Colorfulness#Saturation" title="Colorfulness" class="wl">s</a>, <a href="/en/Brightness" title="Brightness" class="wl">v</a>)</span></th><td class="infobox-data"><span class="nowrap">(240°, 100%, 100%)</span></td></tr><tr><th scope="row" class="infobox-label"><span class="nowrap"><a href="/en/CIELChuv" title="CIELChuv" class="mw-redirect wl">CIELCh<sub>uv</sub></a> (<a href="/en/Lightness" title="Lightness" class="wl">L</a>, <a href="/en/Colorfulness" title="Colorfulness" class="wl">C</a>, <a href="/en/Hue" title="Hue" class="wl">h</a>)</span></th><td class="infobox-data"><span class="nowrap">(32, 131, 266°)</span></td></tr><tr><th scope="row" class="infobox-label">Source</th><td class="infobox-data"><a href="/en/HTML_color_names" title="HTML color names" class="mw-redirect wl">HTML/CSS</a><span class="mw-ref reference" id="cite_ref-css3-color_1-0"><a href="#cite_note-css3-color-1" style="counter-reset: mw-Ref 1;"><span class="mw-reflink-text">[1]</span></a></span></td></tr><tr><td colspan="2" class="infobox-full-data"><b>B</b>: Normalized to [0–255] (byte)<br><b>H</b>: Normalized to [0–100] (hundred)</td></tr></tbody></table> <footer class='mobile-collapse-footer mobile-collapse-btn'><b>Close</b> <span class='arrow'>▲</span></footer></div>

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<p>Blue has been an important colour in art and decoration since ancient times. The semi-precious stone <a href="/en/Lapis_lazuli" title="Lapis lazuli" class="wl">lapis lazuli</a> was used in ancient Egypt for jewellery and ornament and later, in the <a href="/en/Renaissance" title="Renaissance" class="wl">Renaissance</a>, to make the pigment <a href="/en/Ultramarine" title="Ultramarine" class="wl">ultramarine</a>, the most expensive of all pigments. In the eighth century Chinese artists used <a href="/en/Cobalt_blue" title="Cobalt blue" class="wl">cobalt blue</a> to colour fine <a href="/en/Blue_and_white_porcelain" title="Blue and white porcelain" class="mw-redirect wl">blue and white porcelain</a>. In the <a href="/en/Middle_Ages" title="Middle Ages" class="wl">Middle Ages</a>, European artists used it in the windows of <a href="/en/Cathedral" title="Cathedral" class="wl">cathedrals</a>. Europeans wore clothing coloured with the vegetable dye <a href="/en/Woad" title="Woad" class="mw-redirect wl">woad</a> until it was replaced by the finer <a href="/en/Indigo_dye" title="Indigo dye" class="wl">indigo</a> from America. In the 19th century, synthetic blue dyes and pigments gradually replaced organic dyes and mineral pigments. Dark blue became a common colour for military uniforms and later, in the late 20th century, for business suits. Because blue has commonly been associated with harmony, it was chosen as the colour of the flags of the <a href="/en/United_Nations" title="United Nations" class="wl">United Nations</a> and the <a href="/en/European_Union" title="European Union" class="wl">European Union</a>.<span class="mw-ref reference" id="cite_ref-3"><a href="#cite_note-3" style="counter-reset: mw-Ref 3;"><span class="mw-reflink-text">[3]</span></a></span></p>

<p>Surveys in the US and Europe show that blue is the colour most commonly associated with harmony, faithfulness, confidence, distance, infinity, the imagination, cold, and occasionally with sadness.<span class="mw-ref reference" id="cite_ref-FOOTNOTEHeller200924_4-0"><a href="#cite_note-FOOTNOTEHeller200924-4" style="counter-reset: mw-Ref 4;"><span class="mw-reflink-text">[4]</span></a></span> In US and European public opinion polls it is the most popular colour, chosen by almost half of both men and women as their favourite colour.<span class="mw-ref reference" id="cite_ref-FOOTNOTEHeller200922_5-0"><a href="#cite_note-FOOTNOTEHeller200922-5" style="counter-reset: mw-Ref 5;"><span class="mw-reflink-text">[5]</span></a></span> The same surveys also showed that blue was the colour most associated with the masculine, just ahead of black, and was also the colour most associated with intelligence, knowledge, calm, and concentration.<span class="mw-ref reference" id="cite_ref-FOOTNOTEHeller200924_4-1"><a href="#cite_note-FOOTNOTEHeller200924-4" style="counter-reset: mw-Ref 4;"><span class="mw-reflink-text">[4]</span></a></span></p>



Blue is one of the three primary colours in the RYB colour model , as well as in the RGB colour model. It lies between violet and cyan on the spectrum of visible light. The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colours; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective. Blue has been an important colour in art and decoration since ancient times. The semi-precious stone lapis lazuli was used in ancient Egypt for jewellery and ornament and later, in the Renaissance, to make the pigment ultramarine, the most expensive of all pigments. In the eighth century Chinese artists used cobalt blue to colour fine blue and white porcelain. In the Middle Ages, European artists used it in the windows of cathedrals. Europeans wore clothing coloured with the vegetable dye woad until it was replaced by the finer indigo from America. In the 19th century, synthetic blue dyes and pigments gradually replaced organic dyes and mineral pigments. Dark blue became a common colour for military uniforms and later, in the late 20th century, for business suits. Because blue has commonly been associated with harmony, it was chosen as the colour of the flags of the United Nations and the European Union. 