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class="page-actions-menu__list-item"> <a role="button" id="ca-watch" href="/w/index.php?title=Special:UserLogin&returnto=Lightness" data-event-name="menu.watch" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet menu__item--page-actions-watch"> <span class="minerva-icon minerva-icon--star"></span> <span>Watch</span> </a> </li> <li id="page-actions-edit" class="page-actions-menu__list-item"> <a role="button" id="ca-edit" href="/w/index.php?title=Lightness&action=edit" data-event-name="menu.edit" data-mw="interface" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet edit-page menu__item--page-actions-edit"> <span class="minerva-icon minerva-icon--edit"></span> <span>Edit</span> </a> </li> </ul> </nav>  <div id="mw-content-subtitle"></div> </div> <div id="bodyContent" class="content"> <div id="mw-content-text" class="mw-body-content"><script>function mfTempOpenSection(id){var block=document.getElementById("mf-section-"+id);block.className+=" open-block";block.previousSibling.className+=" open-block";}</script><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><section class="mf-section-0" id="mf-section-0"> <p class="mw-empty-elt"> </p> <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">For other uses, see <a href="/wiki/Lightness_(disambiguation)" class="mw-disambig" title="Lightness (disambiguation)">Lightness (disambiguation)</a>.</div> <p><b>Lightness</b> is a visual perception of the <a href="/wiki/Luminance" title="Luminance">luminance</a> <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle (L)}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo stretchy="false">(</mo> <mi>L</mi> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle (L)}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/5cdb05b4c6f0051cecdb0afdbca0b5b55b5e89d5" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:3.392ex; height:2.843ex;" alt="{\displaystyle (L)}"></span> of an object. It is often judged relative to a similarly lit object. In <a href="/wiki/Colorimetry" title="Colorimetry">colorimetry</a> and <a href="/wiki/Color_appearance_model" title="Color appearance model">color appearance models</a>, lightness is a prediction of how an illuminated <a href="/wiki/Color" title="Color">color</a> will appear to a standard observer. While luminance is a linear measurement of light, lightness is a linear prediction of the human perception of that light. </p><figure class="mw-halign-right" typeof="mw:File/Frame"><a href="/wiki/File:ColorValue.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/45/ColorValue.svg/230px-ColorValue.svg.png" decoding="async" width="230" height="480" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/45/ColorValue.svg/345px-ColorValue.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/45/ColorValue.svg/460px-ColorValue.svg.png 2x" data-file-width="230" data-file-height="480"></a><figcaption>Three <a href="/wiki/Hue" title="Hue">hues</a> in the <a href="/wiki/Munsell_color_system" title="Munsell color system">Munsell color model</a>. Each color differs in value from top to bottom in equal perception steps. The right column undergoes a dramatic change in perceived color.</figcaption></figure> <p>This distinction is meaningful because human vision's lightness perception is non-linear relative to light. Doubling the quantity of light does not result in a doubling in perceived lightness, only a modest increase. </p><p>The symbol for perceptual lightness is usually either <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle J}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>J</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle J}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/359e4f407b49910e02c27c2f52e87a36cd74c053" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.471ex; height:2.176ex;" alt="{\displaystyle J}"></span> as used in <a href="/wiki/CIECAM02" title="CIECAM02">CIECAM02</a> or <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle L^{*}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>L</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>∗</mo> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle L^{*}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/d9a3547ba2f3cc5cb4463473815f227092b4766a" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.637ex; height:2.343ex;" alt="{\displaystyle L^{*}}"></span> as used in <a href="/wiki/CIELAB" class="mw-redirect" title="CIELAB">CIELAB</a> and <a href="/wiki/CIELUV" title="CIELUV">CIELUV</a>. <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle L^{*}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>L</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>∗</mo> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle L^{*}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/d9a3547ba2f3cc5cb4463473815f227092b4766a" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.637ex; height:2.343ex;" alt="{\displaystyle L^{*}}"></span> ("Lstar") is not to be confused with <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle L}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>L</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle L}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/103168b86f781fe6e9a4a87b8ea1cebe0ad4ede8" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.583ex; height:2.176ex;" alt="{\displaystyle L}"></span> as used for luminance. In some color ordering systems such as <a href="/wiki/Munsell_color_system" title="Munsell color system">Munsell</a>, Lightness is referenced as <b>value</b>. </p><p><a href="/wiki/Chiaroscuro" title="Chiaroscuro">Chiaroscuro</a> and <a href="/wiki/Tenebrism" title="Tenebrism">Tenebrism</a> both take advantage of dramatic contrasts of value to heighten drama in art. Artists may also employ <a href="/wiki/Shading" title="Shading">shading</a>, subtle manipulation of value. </p> <div id="toc" class="toc" role="navigation" aria-labelledby="mw-toc-heading"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="display:none"><div class="toctitle" lang="en" dir="ltr"><h2 id="mw-toc-heading">Contents</h2><span class="toctogglespan"><label class="toctogglelabel" for="toctogglecheckbox"></label></span></div> <ul> <li class="toclevel-1 tocsection-1"><a href="#Lightness_in_different_colorspaces"><span class="tocnumber">1</span> <span class="toctext">Lightness in different colorspaces</span></a></li> <li class="toclevel-1 tocsection-2"><a href="#Relationship_to_value_and_relative_luminance"><span class="tocnumber">2</span> <span class="toctext">Relationship to value and relative luminance</span></a> <ul> <li class="toclevel-2 tocsection-3"><a href="#1920"><span class="tocnumber">2.1</span> <span class="toctext">1920</span></a></li> <li class="toclevel-2 tocsection-4"><a href="#1933"><span class="tocnumber">2.2</span> <span class="toctext">1933</span></a></li> <li class="toclevel-2 tocsection-5"><a href="#1943"><span class="tocnumber">2.3</span> <span class="toctext">1943</span></a></li> <li class="toclevel-2 tocsection-6"><a href="#1943_2"><span class="tocnumber">2.4</span> <span class="toctext">1943</span></a></li> <li class="toclevel-2 tocsection-7"><a href="#1944"><span class="tocnumber">2.5</span> <span class="toctext">1944</span></a></li> <li class="toclevel-2 tocsection-8"><a href="#1955"><span class="tocnumber">2.6</span> <span class="toctext">1955</span></a></li> <li class="toclevel-2 tocsection-9"><a href="#1958"><span class="tocnumber">2.7</span> <span class="toctext">1958</span></a></li> <li class="toclevel-2 tocsection-10"><a href="#1964"><span class="tocnumber">2.8</span> <span class="toctext">1964</span></a></li> <li class="toclevel-2 tocsection-11"><a href="#1976"><span class="tocnumber">2.9</span> <span class="toctext">1976</span></a></li> <li class="toclevel-2 tocsection-12"><a href="#1997"><span class="tocnumber">2.10</span> <span class="toctext">1997</span></a></li> <li class="toclevel-2 tocsection-13"><a href="#2002"><span class="tocnumber">2.11</span> <span class="toctext">2002</span></a></li> </ul> </li> <li class="toclevel-1 tocsection-14"><a href="#Other_psychological_effects"><span class="tocnumber">3</span> <span class="toctext">Other psychological effects</span></a></li> <li class="toclevel-1 tocsection-15"><a href="#See_also"><span class="tocnumber">4</span> <span class="toctext">See also</span></a></li> <li class="toclevel-1 tocsection-16"><a href="#References"><span class="tocnumber">5</span> <span class="toctext">References</span></a></li> <li class="toclevel-1 tocsection-17"><a href="#External_links"><span class="tocnumber">6</span> <span class="toctext">External links</span></a></li> </ul> </div> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(1)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Lightness_in_different_colorspaces">Lightness in different colorspaces</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=1" title="Edit section: Lightness in different colorspaces" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-1 collapsible-block" id="mf-section-1"> <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 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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:402px;max-width:402px"><div class="trow"><div class="tsingle" style="width:199px;max-width:199px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Srgb-in-cielab.png" class="mw-file-description"><noscript><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/60/Srgb-in-cielab.png/197px-Srgb-in-cielab.png" decoding="async" width="197" height="167" class="mw-file-element" data-file-width="575" data-file-height="487"></noscript><span class="lazy-image-placeholder" style="width: 197px;height: 167px;" data-src="//upload.wikimedia.org/wikipedia/commons/thumb/6/60/Srgb-in-cielab.png/197px-Srgb-in-cielab.png" data-alt="" data-width="197" data-height="167" data-srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/60/Srgb-in-cielab.png/296px-Srgb-in-cielab.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/60/Srgb-in-cielab.png/394px-Srgb-in-cielab.png 2x" data-class="mw-file-element"> </span></a></span></div><div class="thumbcaption">Fig 2a. The <a href="/wiki/SRGB" title="SRGB">sRGB</a> gamut mapped in CIELAB space. Notice that the lines pointing to the red, green, and blue primaries are not evenly spaced by hue angle, and are of unequal length. The primaries also have different <i>L</i>* values.</div></div><div class="tsingle" style="width:199px;max-width:199px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Adobergb-in-cielab.png" class="mw-file-description"><noscript><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/3/33/Adobergb-in-cielab.png/197px-Adobergb-in-cielab.png" decoding="async" width="197" height="167" class="mw-file-element" data-file-width="575" data-file-height="487"></noscript><span class="lazy-image-placeholder" style="width: 197px;height: 167px;" data-src="//upload.wikimedia.org/wikipedia/commons/thumb/3/33/Adobergb-in-cielab.png/197px-Adobergb-in-cielab.png" data-alt="" data-width="197" data-height="167" data-srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/33/Adobergb-in-cielab.png/296px-Adobergb-in-cielab.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/33/Adobergb-in-cielab.png/394px-Adobergb-in-cielab.png 2x" data-class="mw-file-element"> </span></a></span></div><div class="thumbcaption">Fig 2b. The <a href="/wiki/Adobe_RGB_color_space" title="Adobe RGB color space">Adobe RGB</a> gamut mapped in CIELAB space. Also notice that these two RGB spaces have different gamuts, and thus will have different HSL and HSV representations.</div></div></div></div></div> <p>In some colorspaces or color systems such as Munsell, <a href="/wiki/HCL_color_space" title="HCL color space">HCL</a>, and CIELAB, the lightness (value) achromatically constrains the maximum and minimum limits, and operates independently of the <a href="/wiki/Hue" title="Hue">hue</a> and <a href="/wiki/Chroma_(color)" class="mw-redirect" title="Chroma (color)">chroma</a>. For example Munsell value 0 is pure black, and value 10 is pure white. Colors with a discernible hue must therefore have values in between these extremes. </p><p>In a <a href="/wiki/Subtractive_color" title="Subtractive color">subtractive color</a> model (e.g. paint, dye, or ink) lightness changes to a color through various <a href="/wiki/Tint,_shade_and_tone" title="Tint, shade and tone">tints, shades, or tones</a> can be achieved by adding white, black, or grey respectively. This also reduces <a href="/wiki/Colorfulness" title="Colorfulness">saturation</a>. </p><p>In <a href="/wiki/HSL_and_HSV" title="HSL and HSV">HSL and HSV</a>, the displayed luminance is relative to the hue and chroma for a given lightness value, in other words the selected lightness value does not predict the actual displayed luminance nor the perception thereof. Both systems use coordinate triples, where many triples can map onto the same color. </p><p>In HSV, all triples with value 0 are pure black. If the hue and saturation are held constant, then increasing the value increases the luminance, such that a value of 1 is the lightest color with the given hue and saturation. HSL is similar, except that all triples with lightness 1 are pure white. In both models, all pure saturated colors indicate the same lightness or value, but this does not relate to the displayed luminance which is determined by the hue. I.e. yellow is higher luminance than blue, even if the lightness value is set at a given number. </p><p>While HSL, HSV, and similar spaces serve well enough to choose or adjust a single color, they are not perceptually uniform. They trade off accuracy for computational simplicity, as they were created in an era where computer technology was restricted in performance.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>If we take an image and extract the hue, saturation, and lightness or value components for a given <a href="/wiki/Color_space" title="Color space">color space</a>, we will see that they may differ substantially from a different color space or model. For example, examine the following images of a fire breather (<span class="nowrap">fig. 1</span>). The original is in the sRGB color space. CIELAB <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle L^{*}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>L</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>∗</mo> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle L^{*}}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/d9a3547ba2f3cc5cb4463473815f227092b4766a" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.637ex; height:2.343ex;" alt="{\displaystyle L^{*}}"></noscript><span class="lazy-image-placeholder" style="width: 2.637ex;height: 2.343ex;vertical-align: -0.338ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/d9a3547ba2f3cc5cb4463473815f227092b4766a" data-alt="{\displaystyle L^{*}}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span> is a perceptually uniform lightness prediction that is derived from luminance <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Y}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Y</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Y}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/961d67d6b454b4df2301ac571808a3538b3a6d3f" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.171ex; width:1.773ex; height:2.009ex;" alt="{\displaystyle Y}"></noscript><span class="lazy-image-placeholder" style="width: 1.773ex;height: 2.009ex;vertical-align: -0.171ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/961d67d6b454b4df2301ac571808a3538b3a6d3f" data-alt="{\displaystyle Y}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span>, but discards the <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle X}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>X</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle X}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/68baa052181f707c662844a465bfeeb135e82bab" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.98ex; height:2.176ex;" alt="{\displaystyle X}"></noscript><span class="lazy-image-placeholder" style="width: 1.98ex;height: 2.176ex;vertical-align: -0.338ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/68baa052181f707c662844a465bfeeb135e82bab" data-alt="{\displaystyle X}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span> and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Z}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Z</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Z}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1cc6b75e09a8aa3f04d8584b11db534f88fb56bd" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.68ex; height:2.176ex;" alt="{\displaystyle Z}"></noscript><span class="lazy-image-placeholder" style="width: 1.68ex;height: 2.176ex;vertical-align: -0.338ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1cc6b75e09a8aa3f04d8584b11db534f88fb56bd" data-alt="{\displaystyle Z}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span>, of the <a href="/wiki/CIE_1931_color_space" title="CIE 1931 color space">CIE XYZ color space</a>. Notice this appears similar in perceived lightness to the original color image. Luma <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle (Y^{\prime })}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo stretchy="false">(</mo> <msup> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi class="MJX-variant" mathvariant="normal">′</mi> </mrow> </msup> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle (Y^{\prime })}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f43f789d74a2b562acbd9f6fc9904097ba820929" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:4.394ex; height:3.009ex;" alt="{\displaystyle (Y^{\prime })}"></noscript><span class="lazy-image-placeholder" style="width: 4.394ex;height: 3.009ex;vertical-align: -0.838ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f43f789d74a2b562acbd9f6fc9904097ba820929" data-alt="{\displaystyle (Y^{\prime })}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span> is a gamma-encoded luminance component of some video encoding systems such as <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle (Y^{\prime }IQ)}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo stretchy="false">(</mo> <msup> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi class="MJX-variant" mathvariant="normal">′</mi> </mrow> </msup> <mi>I</mi> <mi>Q</mi> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle (Y^{\prime }IQ)}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c5188089f15b85b66326c6c473645535dc8cb33c" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:7.404ex; height:3.009ex;" alt="{\displaystyle (Y^{\prime }IQ)}"></noscript><span class="lazy-image-placeholder" style="width: 7.404ex;height: 3.009ex;vertical-align: -0.838ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c5188089f15b85b66326c6c473645535dc8cb33c" data-alt="{\displaystyle (Y^{\prime }IQ)}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span> and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle (Y^{\prime }UV)}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo stretchy="false">(</mo> <msup> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi class="MJX-variant" mathvariant="normal">′</mi> </mrow> </msup> <mi>U</mi> <mi>V</mi> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle (Y^{\prime }UV)}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/2c6ddd307341cc33bcb367f41422f3c2736e8d07" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:7.964ex; height:3.009ex;" alt="{\displaystyle (Y^{\prime }UV)}"></noscript><span class="lazy-image-placeholder" style="width: 7.964ex;height: 3.009ex;vertical-align: -0.838ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/2c6ddd307341cc33bcb367f41422f3c2736e8d07" data-alt="{\displaystyle (Y^{\prime }UV)}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span>. It is roughly similar, but differs at high chroma, deviating most from an achromatic signal such as linear luminance <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Y}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Y</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Y}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/961d67d6b454b4df2301ac571808a3538b3a6d3f" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.171ex; width:1.773ex; height:2.009ex;" alt="{\displaystyle Y}"></noscript><span class="lazy-image-placeholder" style="width: 1.773ex;height: 2.009ex;vertical-align: -0.171ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/961d67d6b454b4df2301ac571808a3538b3a6d3f" data-alt="{\displaystyle Y}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span> or non-linear lightness <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle L^{*}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>L</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>∗</mo> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle L^{*}}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/d9a3547ba2f3cc5cb4463473815f227092b4766a" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.637ex; height:2.343ex;" alt="{\displaystyle L^{*}}"></noscript><span class="lazy-image-placeholder" style="width: 2.637ex;height: 2.343ex;vertical-align: -0.338ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/d9a3547ba2f3cc5cb4463473815f227092b4766a" data-alt="{\displaystyle L^{*}}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span>. HSL <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle L}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>L</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle L}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/103168b86f781fe6e9a4a87b8ea1cebe0ad4ede8" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.583ex; height:2.176ex;" alt="{\displaystyle L}"></noscript><span class="lazy-image-placeholder" style="width: 1.583ex;height: 2.176ex;vertical-align: -0.338ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/103168b86f781fe6e9a4a87b8ea1cebe0ad4ede8" data-alt="{\displaystyle L}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span> and HSV <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>V</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle V}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/af0f6064540e84211d0ffe4dac72098adfa52845" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.787ex; height:2.176ex;" alt="{\displaystyle V}"></noscript><span class="lazy-image-placeholder" style="width: 1.787ex;height: 2.176ex;vertical-align: -0.338ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/af0f6064540e84211d0ffe4dac72098adfa52845" data-alt="{\displaystyle V}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span> are neither perceptually uniform, nor uniform as to luminance. </p> <div style="clear:both;" class=""></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1237032888/mw-parser-output/.tmulti"><div class="thumb tmulti tnone center"><div class="thumbinner multiimageinner" style="width:672px;max-width:672px"><div class="trow"><div class="tsingle" style="width:222px;max-width:222px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Fire_breathing_2_Luc_Viatour.jpg" class="mw-file-description"><noscript><img alt="A full-color image shows a high-contrast and quite dramatic scene of a fire breather with a large orange-yellow flame extending from his lips. He wears dark but colorful orange-red clothing." src="//upload.wikimedia.org/wikipedia/commons/thumb/0/02/Fire_breathing_2_Luc_Viatour.jpg/220px-Fire_breathing_2_Luc_Viatour.jpg" decoding="async" width="220" height="162" class="mw-file-element" data-file-width="3288" data-file-height="2416"></noscript><span class="lazy-image-placeholder" style="width: 220px;height: 162px;" data-src="//upload.wikimedia.org/wikipedia/commons/thumb/0/02/Fire_breathing_2_Luc_Viatour.jpg/220px-Fire_breathing_2_Luc_Viatour.jpg" data-alt="A full-color image shows a high-contrast and quite dramatic scene of a fire breather with a large orange-yellow flame extending from his lips. He wears dark but colorful orange-red clothing." data-width="220" data-height="162" data-srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/02/Fire_breathing_2_Luc_Viatour.jpg/330px-Fire_breathing_2_Luc_Viatour.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/02/Fire_breathing_2_Luc_Viatour.jpg/440px-Fire_breathing_2_Luc_Viatour.jpg 2x" data-class="mw-file-element"> </span></a></span></div><div class="thumbcaption">Fig. 1a. Color photograph (sRGB color space).</div></div><div class="tsingle" style="width:222px;max-width:222px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Fire-breather_CIELAB_L*.jpg" class="mw-file-description"><noscript><img alt="A grayscale image showing the CIELAB lightness component of the photograph appears to be a faithful rendering of the scene: it looks roughly like a black-and-white photograph taken on panchromatic film would look, with clear detail in the flame, which is much brighter than the man's outfit or the background." src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e5/Fire-breather_CIELAB_L%2A.jpg/220px-Fire-breather_CIELAB_L%2A.jpg" decoding="async" width="220" height="162" class="mw-file-element" data-file-width="3288" data-file-height="2416"></noscript><span class="lazy-image-placeholder" style="width: 220px;height: 162px;" data-src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e5/Fire-breather_CIELAB_L%2A.jpg/220px-Fire-breather_CIELAB_L%2A.jpg" data-alt="A grayscale image showing the CIELAB lightness component of the photograph appears to be a faithful rendering of the scene: it looks roughly like a black-and-white photograph taken on panchromatic film would look, with clear detail in the flame, which is much brighter than the man's outfit or the background." data-width="220" data-height="162" data-srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e5/Fire-breather_CIELAB_L%2A.jpg/330px-Fire-breather_CIELAB_L%2A.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e5/Fire-breather_CIELAB_L%2A.jpg/440px-Fire-breather_CIELAB_L%2A.jpg 2x" data-class="mw-file-element"> </span></a></span></div><div class="thumbcaption">Fig. 1b. CIELAB <i>L</i>* (further transformed back to sRGB for consistent display).</div></div><div class="tsingle" style="width:222px;max-width:222px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Fire-breather_601_Luma_Y%27.jpg" class="mw-file-description"><noscript><img alt="A grayscale image showing the luma appears roughly similar to the CIELAB lightness image, but is a bit brighter in areas which were originally very colorful." src="//upload.wikimedia.org/wikipedia/commons/thumb/2/28/Fire-breather_601_Luma_Y%27.jpg/220px-Fire-breather_601_Luma_Y%27.jpg" decoding="async" width="220" height="162" class="mw-file-element" data-file-width="3288" data-file-height="2416"></noscript><span class="lazy-image-placeholder" style="width: 220px;height: 162px;" data-src="//upload.wikimedia.org/wikipedia/commons/thumb/2/28/Fire-breather_601_Luma_Y%27.jpg/220px-Fire-breather_601_Luma_Y%27.jpg" data-alt="A grayscale image showing the luma appears roughly similar to the CIELAB lightness image, but is a bit brighter in areas which were originally very colorful." data-width="220" data-height="162" data-srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/28/Fire-breather_601_Luma_Y%27.jpg/330px-Fire-breather_601_Luma_Y%27.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/28/Fire-breather_601_Luma_Y%27.jpg/440px-Fire-breather_601_Luma_Y%27.jpg 2x" data-class="mw-file-element"> </span></a></span></div><div class="thumbcaption">Fig. 1c. Rec. 601 luma <span class="nowrap"><i>Y<span class="nowrap" style="padding-left:0.05em;">′</span></i></span>.</div></div></div></div></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1237032888/mw-parser-output/.tmulti"><div class="thumb tmulti tnone center"><div class="thumbinner multiimageinner" style="width:672px;max-width:672px"><div class="trow"><div class="tsingle" style="width:222px;max-width:222px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Fire-breather_mean(R,G,B)_I.jpg" class="mw-file-description"><noscript><img alt="A grayscale image showing the component average (HSI intensity) of the photograph is much a less convincing facsimile of the color photograph, with reduced contrast, especially with its flame darker than in the original." src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Fire-breather_mean%28R%2CG%2CB%29_I.jpg/220px-Fire-breather_mean%28R%2CG%2CB%29_I.jpg" decoding="async" width="220" height="162" class="mw-file-element" data-file-width="3288" data-file-height="2416"></noscript><span class="lazy-image-placeholder" style="width: 220px;height: 162px;" data-src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Fire-breather_mean%28R%2CG%2CB%29_I.jpg/220px-Fire-breather_mean%28R%2CG%2CB%29_I.jpg" data-alt="A grayscale image showing the component average (HSI intensity) of the photograph is much a less convincing facsimile of the color photograph, with reduced contrast, especially with its flame darker than in the original." data-width="220" data-height="162" data-srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Fire-breather_mean%28R%2CG%2CB%29_I.jpg/330px-Fire-breather_mean%28R%2CG%2CB%29_I.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Fire-breather_mean%28R%2CG%2CB%29_I.jpg/440px-Fire-breather_mean%28R%2CG%2CB%29_I.jpg 2x" data-class="mw-file-element"> </span></a></span></div><div class="thumbcaption">Fig. 1d. Component average: "intensity" <i>I</i>.</div></div><div class="tsingle" style="width:222px;max-width:222px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Fire-breather_HSV_V.jpg" class="mw-file-description"><noscript><img alt="A grayscale image showing the HSV value component of the photograph leaves the flame completely white (in photographer's parlance, "blown out"), and the man's clothing much too bright." src="//upload.wikimedia.org/wikipedia/commons/thumb/4/43/Fire-breather_HSV_V.jpg/220px-Fire-breather_HSV_V.jpg" decoding="async" width="220" height="162" class="mw-file-element" data-file-width="3288" data-file-height="2416"></noscript><span class="lazy-image-placeholder" style="width: 220px;height: 162px;" data-src="//upload.wikimedia.org/wikipedia/commons/thumb/4/43/Fire-breather_HSV_V.jpg/220px-Fire-breather_HSV_V.jpg" data-alt="A grayscale image showing the HSV value component of the photograph leaves the flame completely white (in photographer's parlance, "blown out"), and the man's clothing much too bright." data-width="220" data-height="162" data-srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/43/Fire-breather_HSV_V.jpg/330px-Fire-breather_HSV_V.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/43/Fire-breather_HSV_V.jpg/440px-Fire-breather_HSV_V.jpg 2x" data-class="mw-file-element"> </span></a></span></div><div class="thumbcaption">Fig. 1e. HSV value <i>V</i>.</div></div><div class="tsingle" style="width:222px;max-width:222px"><div class="thumbimage"><span typeof="mw:File"><a href="/wiki/File:Fire-breather_HSL_L.jpg" class="mw-file-description"><noscript><img alt="A grayscale image showing the HSL lightness component of the photograph renders the flame, as approximately middle gray, and ruins the dramatic effect of the original by radically reducing its contrast." src="//upload.wikimedia.org/wikipedia/commons/thumb/0/06/Fire-breather_HSL_L.jpg/220px-Fire-breather_HSL_L.jpg" decoding="async" width="220" height="162" class="mw-file-element" data-file-width="3288" data-file-height="2416"></noscript><span class="lazy-image-placeholder" style="width: 220px;height: 162px;" data-src="//upload.wikimedia.org/wikipedia/commons/thumb/0/06/Fire-breather_HSL_L.jpg/220px-Fire-breather_HSL_L.jpg" data-alt="A grayscale image showing the HSL lightness component of the photograph renders the flame, as approximately middle gray, and ruins the dramatic effect of the original by radically reducing its contrast." data-width="220" data-height="162" data-srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/06/Fire-breather_HSL_L.jpg/330px-Fire-breather_HSL_L.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/06/Fire-breather_HSL_L.jpg/440px-Fire-breather_HSL_L.jpg 2x" data-class="mw-file-element"> </span></a></span></div><div class="thumbcaption">Fig. 1f. HSL lightness <i>L</i>.</div></div></div></div></div> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(2)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Relationship_to_value_and_relative_luminance">Relationship to value and relative luminance</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=2" title="Edit section: Relationship to value and relative luminance" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-2 collapsible-block" id="mf-section-2"> <p>The <a href="/wiki/Munsell_color_system" title="Munsell color system">Munsell value</a> has long been used as a <a href="/wiki/Color_difference#Tolerance" title="Color difference">perceptually uniform</a> lightness scale. A question of interest is the relationship between the Munsell value scale and the <a href="/wiki/Relative_luminance" title="Relative luminance">relative luminance</a>. Aware of the <a href="/wiki/Weber%E2%80%93Fechner_law" title="Weber–Fechner law">Weber–Fechner law</a>, <a href="/wiki/Albert_Henry_Munsell" title="Albert Henry Munsell">Albert Munsell</a> remarked "Should we use a logarithmic curve or curve of squares?"<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> Neither option turned out to be quite correct; scientists eventually converged on a roughly cube-root curve, consistent with the <a href="/wiki/Stevens%27s_power_law" title="Stevens's power law">Stevens's power law</a> for brightness perception, reflecting the fact that lightness is proportional to the number of nerve impulses per nerve fiber per unit time.<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> The remainder of this section is a chronology of lightness models, leading to <a href="/wiki/CIECAM02" title="CIECAM02">CIECAM02</a>. </p><p><i>Note.</i> – Munsell's <i>V</i> runs from 0 to 10, while <i>Y</i> typically runs from 0 to 100 (often interpreted as a percentage). Typically, the relative luminance is normalized so that the "reference white" (say, <a href="/wiki/Magnesium_oxide" title="Magnesium oxide">magnesium oxide</a>) has a tristimulus value of <span class="nowrap"><i>Y</i> = 100</span>. Since the reflectance of magnesium oxide (MgO) relative to the <a href="/wiki/Diffuser_(optics)#Perfect_reflecting_diffuser" title="Diffuser (optics)">perfect reflecting diffuser</a> is 97.5%, <span class="nowrap"><i>V</i> = 10</span> corresponds to <span class="nowrap"><i>Y</i> = <style data-mw-deduplicate="TemplateStyles:r1214402035">.mw-parser-output .sfrac{white-space:nowrap}.mw-parser-output .sfrac.tion,.mw-parser-output .sfrac .tion{display:inline-block;vertical-align:-0.5em;font-size:85%;text-align:center}.mw-parser-output .sfrac .num{display:block;line-height:1em;margin:0.0em 0.1em;border-bottom:1px solid}.mw-parser-output .sfrac .den{display:block;line-height:1em;margin:0.1em 0.1em}.mw-parser-output .sr-only{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}</style><span class="sfrac">⁠<span class="tion"><span class="num">100</span><span class="sr-only">/</span><span class="den">97.5</span></span>⁠</span>% ≈ 102.6</span> if MgO is used as the reference.<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> </p> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Lightness_approximations.svg" class="mw-file-description"><noscript><img src="//upload.wikimedia.org/wikipedia/en/thumb/b/bd/Lightness_approximations.svg/500px-Lightness_approximations.svg.png" decoding="async" width="500" height="400" class="mw-file-element" data-file-width="600" data-file-height="480"></noscript><span class="lazy-image-placeholder" style="width: 500px;height: 400px;" data-src="//upload.wikimedia.org/wikipedia/en/thumb/b/bd/Lightness_approximations.svg/500px-Lightness_approximations.svg.png" data-width="500" data-height="400" data-srcset="//upload.wikimedia.org/wikipedia/en/thumb/b/bd/Lightness_approximations.svg/750px-Lightness_approximations.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/b/bd/Lightness_approximations.svg/1000px-Lightness_approximations.svg.png 2x" data-class="mw-file-element"> </span></a><figcaption>Observe that the lightness is 50% for a relative luminance of around 18% relative to the reference white.</figcaption></figure> <div class="mw-heading mw-heading3"><h3 id="1920">1920</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=3" title="Edit section: 1920" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p><a href="/wiki/Irwin_G._Priest" title="Irwin G. Priest">Irwin Priest</a>, <a href="/wiki/Kasson_S._Gibson" title="Kasson S. Gibson">Kasson Gibson</a>, and Harry McNicholas provide a basic estimate of the Munsell value (with <i>Y</i> running from 0 to 1 in this case):<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> </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V=10{\sqrt {Y}}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>V</mi> <mo>=</mo> <mn>10</mn> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mi>Y</mi> </msqrt> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle V=10{\sqrt {Y}}.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/77596efcaeff412cccf4862ad41cfaa49774d006" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:11.567ex; height:3.009ex;" alt="{\displaystyle V=10{\sqrt {Y}}.}"></noscript><span class="lazy-image-placeholder" style="width: 11.567ex;height: 3.009ex;vertical-align: -0.671ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/77596efcaeff412cccf4862ad41cfaa49774d006" data-alt="{\displaystyle V=10{\sqrt {Y}}.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <div class="mw-heading mw-heading3"><h3 id="1933">1933</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=4" title="Edit section: 1933" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p>Alexander Munsell, <a href="/wiki/Louise_L._Sloan" title="Louise L. Sloan">Louise Sloan</a>, and Isaac Godlove launch a study on the Munsell neutral value scale, considering several proposals relating the relative luminance to the Munsell value, and suggest:<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V^{2}=1.4742Y-0.004743Y^{2}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>V</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mn>1.4742</mn> <mi>Y</mi> <mo>−</mo> <mn>0.004743</mn> <msup> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle V^{2}=1.4742Y-0.004743Y^{2}.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/cb46be35b90a3248b9aa45e4809cdbc2fe0c32f0" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:29.528ex; height:2.843ex;" alt="{\displaystyle V^{2}=1.4742Y-0.004743Y^{2}.}"></noscript><span class="lazy-image-placeholder" style="width: 29.528ex;height: 2.843ex;vertical-align: -0.505ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/cb46be35b90a3248b9aa45e4809cdbc2fe0c32f0" data-alt="{\displaystyle V^{2}=1.4742Y-0.004743Y^{2}.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <div class="mw-heading mw-heading3"><h3 id="1943">1943</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=5" title="Edit section: 1943" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p>Sidney Newhall, <a href="/wiki/Dorothy_Nickerson" title="Dorothy Nickerson">Dorothy Nickerson</a>, and <a href="/wiki/Deane_B._Judd" title="Deane B. Judd">Deane Judd</a> prepare a report for the <a href="/wiki/Optical_Society_of_America" class="mw-redirect" title="Optical Society of America">Optical Society of America</a> (OSA) on Munsell renotation. They suggest a quintic parabola (relating the reflectance in terms of the value):<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> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Y=1.2219V-0.23111V^{2}+0.23951V^{3}-0.021009V^{4}+0.0008404V^{5}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Y</mi> <mo>=</mo> <mn>1.2219</mn> <mi>V</mi> <mo>−</mo> <mn>0.23111</mn> <msup> <mi>V</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <mn>0.23951</mn> <msup> <mi>V</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msup> <mo>−</mo> <mn>0.021009</mn> <msup> <mi>V</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>4</mn> </mrow> </msup> <mo>+</mo> <mn>0.0008404</mn> <msup> <mi>V</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>5</mn> </mrow> </msup> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Y=1.2219V-0.23111V^{2}+0.23951V^{3}-0.021009V^{4}+0.0008404V^{5}.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b97ce405df7572418a72e68d42b0a9c0f6df9016" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:70.985ex; height:2.843ex;" alt="{\displaystyle Y=1.2219V-0.23111V^{2}+0.23951V^{3}-0.021009V^{4}+0.0008404V^{5}.}"></noscript><span class="lazy-image-placeholder" style="width: 70.985ex;height: 2.843ex;vertical-align: -0.505ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b97ce405df7572418a72e68d42b0a9c0f6df9016" data-alt="{\displaystyle Y=1.2219V-0.23111V^{2}+0.23951V^{3}-0.021009V^{4}+0.0008404V^{5}.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <div class="mw-heading mw-heading3"><h3 id="1943_2">1943</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=6" title="Edit section: 1943" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p>Using Table II of the OSA report, <a href="/wiki/Parry_Moon" title="Parry Moon">Parry Moon</a> and <a href="/wiki/Domina_Eberle_Spencer" title="Domina Eberle Spencer">Domina Spencer</a> express the value in terms of the relative luminance:<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> </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V=5\left({\frac {Y}{19.77}}\right)^{0.426}=1.4Y^{0.426}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>V</mi> <mo>=</mo> <mn>5</mn> <msup> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>Y</mi> <mn>19.77</mn> </mfrac> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>0.426</mn> </mrow> </msup> <mo>=</mo> <mn>1.4</mn> <msup> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>0.426</mn> </mrow> </msup> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle V=5\left({\frac {Y}{19.77}}\right)^{0.426}=1.4Y^{0.426}.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/99f964944a5b177b527129d2b327c1b68c7f9159" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:32.175ex; height:6.676ex;" alt="{\displaystyle V=5\left({\frac {Y}{19.77}}\right)^{0.426}=1.4Y^{0.426}.}"></noscript><span class="lazy-image-placeholder" style="width: 32.175ex;height: 6.676ex;vertical-align: -2.505ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/99f964944a5b177b527129d2b327c1b68c7f9159" data-alt="{\displaystyle V=5\left({\frac {Y}{19.77}}\right)^{0.426}=1.4Y^{0.426}.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <div class="mw-heading mw-heading3"><h3 id="1944">1944</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=7" title="Edit section: 1944" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p>Jason Saunderson and B.I. Milner introduce a subtractive constant in the previous expression, for a better fit to the Munsell value.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> Later, <a href="/wiki/Dorothea_Jameson" title="Dorothea Jameson">Dorothea Jameson</a> and <a href="/wiki/Leo_Hurvich" title="Leo Hurvich">Leo Hurvich</a> claim that this corrects for simultaneous <a href="/wiki/Contrast_effect" title="Contrast effect">contrast effects</a>.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup><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> </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V=2.357Y^{0.343}-1.52.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>V</mi> <mo>=</mo> <mn>2.357</mn> <msup> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>0.343</mn> </mrow> </msup> <mo>−</mo> <mn>1.52.</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle V=2.357Y^{0.343}-1.52.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1df6775b666929d4376a30554510559e1c7307d8" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:23.682ex; height:2.843ex;" alt="{\displaystyle V=2.357Y^{0.343}-1.52.}"></noscript><span class="lazy-image-placeholder" style="width: 23.682ex;height: 2.843ex;vertical-align: -0.505ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1df6775b666929d4376a30554510559e1c7307d8" data-alt="{\displaystyle V=2.357Y^{0.343}-1.52.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <div class="mw-heading mw-heading3"><h3 id="1955">1955</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=8" title="Edit section: 1955" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p>Ladd and Pinney of <a href="/wiki/Eastman_Kodak" class="mw-redirect" title="Eastman Kodak">Eastman Kodak</a> are interested in the Munsell value as a perceptually uniform lightness scale for use in <a href="/wiki/Television" title="Television">television</a>. After considering one logarithmic and five <a href="/wiki/Power-law" class="mw-redirect" title="Power-law">power-law</a> functions (per <a href="/wiki/Stevens%27_power_law" class="mw-redirect" title="Stevens' power law">Stevens' power law</a>), they relate value to reflectance by raising the reflectance to the power of 0.352:<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> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V=2.217Y^{0.352}-1.324.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>V</mi> <mo>=</mo> <mn>2.217</mn> <msup> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>0.352</mn> </mrow> </msup> <mo>−</mo> <mn>1.324.</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle V=2.217Y^{0.352}-1.324.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/bbcc40249f1b19c8a2c811ead73745461c2a097d" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:24.844ex; height:2.843ex;" alt="{\displaystyle V=2.217Y^{0.352}-1.324.}"></noscript><span class="lazy-image-placeholder" style="width: 24.844ex;height: 2.843ex;vertical-align: -0.505ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/bbcc40249f1b19c8a2c811ead73745461c2a097d" data-alt="{\displaystyle V=2.217Y^{0.352}-1.324.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <p>Realizing this is quite close to the <a href="/wiki/Cube_root" title="Cube root">cube root</a>, they simplify it to: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V=2.468{\sqrt[{3}]{Y}}-1.636.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>V</mi> <mo>=</mo> <mn>2.468</mn> <mrow class="MJX-TeXAtom-ORD"> <mroot> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </mroot> </mrow> <mo>−</mo> <mn>1.636.</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle V=2.468{\sqrt[{3}]{Y}}-1.636.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/a11aa9ff0861076b644628633a7f654d02cf7599" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:22.675ex; height:3.009ex;" alt="{\displaystyle V=2.468{\sqrt[{3}]{Y}}-1.636.}"></noscript><span class="lazy-image-placeholder" style="width: 22.675ex;height: 3.009ex;vertical-align: -0.671ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/a11aa9ff0861076b644628633a7f654d02cf7599" data-alt="{\displaystyle V=2.468{\sqrt[{3}]{Y}}-1.636.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <div class="mw-heading mw-heading3"><h3 id="1958">1958</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=9" title="Edit section: 1958" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p>Glasser <i>et al.</i> define the lightness as ten times the Munsell value (so that the lightness ranges from 0 to 100):<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> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle L^{\star }=25.29{\sqrt[{3}]{Y}}-18.38.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>L</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>⋆</mo> </mrow> </msup> <mo>=</mo> <mn>25.29</mn> <mrow class="MJX-TeXAtom-ORD"> <mroot> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </mroot> </mrow> <mo>−</mo> <mn>18.38.</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle L^{\star }=25.29{\sqrt[{3}]{Y}}-18.38.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f5f9bc42a89684f42cc30f7f9dee3998a073ddf8" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:23.525ex; height:3.009ex;" alt="{\displaystyle L^{\star }=25.29{\sqrt[{3}]{Y}}-18.38.}"></noscript><span class="lazy-image-placeholder" style="width: 23.525ex;height: 3.009ex;vertical-align: -0.671ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f5f9bc42a89684f42cc30f7f9dee3998a073ddf8" data-alt="{\displaystyle L^{\star }=25.29{\sqrt[{3}]{Y}}-18.38.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <div class="mw-heading mw-heading3"><h3 id="1964">1964</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=10" title="Edit section: 1964" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p><a href="/wiki/G%C3%BCnter_Wyszecki" title="Günter Wyszecki">Günter Wyszecki</a> simplifies this to:<sup id="cite_ref-gunter_15-0" class="reference"><a href="#cite_note-gunter-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle W^{\star }=25{\sqrt[{3}]{Y}}-17.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>W</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>⋆</mo> </mrow> </msup> <mo>=</mo> <mn>25</mn> <mrow class="MJX-TeXAtom-ORD"> <mroot> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </mroot> </mrow> <mo>−</mo> <mn>17.</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle W^{\star }=25{\sqrt[{3}]{Y}}-17.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/7d98acdd192286e0240dac215838273292c81770" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:18.507ex; height:3.009ex;" alt="{\displaystyle W^{\star }=25{\sqrt[{3}]{Y}}-17.}"></noscript><span class="lazy-image-placeholder" style="width: 18.507ex;height: 3.009ex;vertical-align: -0.671ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/7d98acdd192286e0240dac215838273292c81770" data-alt="{\displaystyle W^{\star }=25{\sqrt[{3}]{Y}}-17.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <p>This formula approximates the Munsell value function for <span class="nowrap">1% < <i>Y</i> < 98%</span> (it is not applicable for <span class="nowrap"><i>Y</i> < 1%</span>) and is used for the <a href="/wiki/CIE_1964_color_space" title="CIE 1964 color space">CIE 1964 color space</a>. </p> <div class="mw-heading mw-heading3"><h3 id="1976">1976</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=11" title="Edit section: 1976" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p><a href="/wiki/CIELAB_color_space" title="CIELAB color space">CIELAB</a> uses the following formula: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle L^{\star }=116\left({\frac {Y}{Y_{\mathrm {n} }}}\right)^{\frac {1}{3}}-16.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>L</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>⋆</mo> </mrow> </msup> <mo>=</mo> <mn>116</mn> <msup> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>Y</mi> <msub> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">n</mi> </mrow> </mrow> </msub> </mfrac> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>3</mn> </mfrac> </mrow> </msup> <mo>−</mo> <mn>16.</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle L^{\star }=116\left({\frac {Y}{Y_{\mathrm {n} }}}\right)^{\frac {1}{3}}-16.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/50d480561264b365425171e652faf3c588b6f092" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:23.525ex; height:7.176ex;" alt="{\displaystyle L^{\star }=116\left({\frac {Y}{Y_{\mathrm {n} }}}\right)^{\frac {1}{3}}-16.}"></noscript><span class="lazy-image-placeholder" style="width: 23.525ex;height: 7.176ex;vertical-align: -2.505ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/50d480561264b365425171e652faf3c588b6f092" data-alt="{\displaystyle L^{\star }=116\left({\frac {Y}{Y_{\mathrm {n} }}}\right)^{\frac {1}{3}}-16.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <p>where <i>Y</i><sub>n</sub> is the <a href="/wiki/CIE_XYZ" class="mw-redirect" title="CIE XYZ">CIE XYZ</a> <i>Y</i> tristimulus value of the reference <a href="/wiki/White_point" title="White point">white point</a> (the subscript n suggests "normalized") and is subject to the restriction <span class="nowrap"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num"><i>Y</i></span><span class="sr-only">/</span><span class="den"><i>Y</i><sub>n</sub></span></span>⁠</span> > 0.01</span>. Pauli removes this restriction by computing a <a href="/wiki/Extrapolation#Linear" title="Extrapolation">linear extrapolation</a> which maps <span class="nowrap"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num"><i>Y</i></span><span class="sr-only">/</span><span class="den"><i>Y</i><sub>n</sub></span></span>⁠</span> = 0</span> to <span class="nowrap"><i>L</i>* = 0</span> and is tangent to the formula above at the point at which the linear extension takes effect. First, the transition point is determined to be <span class="nowrap"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num"><i>Y</i></span><span class="sr-only">/</span><span class="den"><i>Y</i><sub>n</sub></span></span>⁠</span> = (<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num">6</span><span class="sr-only">/</span><span class="den">29</span></span>⁠</span>)<sup>3</sup> ≈ 0.008856</span>, then the slope of <span class="nowrap">(<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num">29</span><span class="sr-only">/</span><span class="den">3</span></span>⁠</span>)<sup>3</sup> ≈ 903.3</span> is computed. This gives the two-part function:<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> </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle f(t)={\begin{cases}t^{\frac {1}{3}}&{\text{if }}t>\left({\frac {6}{29}}\right)^{3}\\{\frac {1}{3}}\left({\frac {29}{6}}\right)^{2}t+{\frac {4}{29}}&{\text{otherwise}}\end{cases}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>f</mi> <mo stretchy="false">(</mo> <mi>t</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow> <mo>{</mo> <mtable columnalign="left left" rowspacing=".2em" columnspacing="1em" displaystyle="false"> <mtr> <mtd> <msup> <mi>t</mi> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>3</mn> </mfrac> </mrow> </msup> </mtd> <mtd> <mrow class="MJX-TeXAtom-ORD"> <mtext>if </mtext> </mrow> <mi>t</mi> <mo>></mo> <msup> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>6</mn> <mn>29</mn> </mfrac> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>3</mn> </mfrac> </mrow> <msup> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>29</mn> <mn>6</mn> </mfrac> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mi>t</mi> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>4</mn> <mn>29</mn> </mfrac> </mrow> </mtd> <mtd> <mrow class="MJX-TeXAtom-ORD"> <mtext>otherwise</mtext> </mrow> </mtd> </mtr> </mtable> <mo fence="true" stretchy="true" symmetric="true"></mo> </mrow> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle f(t)={\begin{cases}t^{\frac {1}{3}}&{\text{if }}t>\left({\frac {6}{29}}\right)^{3}\\{\frac {1}{3}}\left({\frac {29}{6}}\right)^{2}t+{\frac {4}{29}}&{\text{otherwise}}\end{cases}}}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/ebbd78b6b901593af9ffd1a401e3f82f526555bb" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -4.505ex; width:38.481ex; height:10.176ex;" alt="{\displaystyle f(t)={\begin{cases}t^{\frac {1}{3}}&{\text{if }}t>\left({\frac {6}{29}}\right)^{3}\\{\frac {1}{3}}\left({\frac {29}{6}}\right)^{2}t+{\frac {4}{29}}&{\text{otherwise}}\end{cases}}}"></noscript><span class="lazy-image-placeholder" style="width: 38.481ex;height: 10.176ex;vertical-align: -4.505ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/ebbd78b6b901593af9ffd1a401e3f82f526555bb" data-alt="{\displaystyle f(t)={\begin{cases}t^{\frac {1}{3}}&{\text{if }}t>\left({\frac {6}{29}}\right)^{3}\\{\frac {1}{3}}\left({\frac {29}{6}}\right)^{2}t+{\frac {4}{29}}&{\text{otherwise}}\end{cases}}}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <p>The lightness is then: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle L^{\star }=116f\left({\frac {Y}{Y_{\mathrm {n} }}}\right)-16.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>L</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>⋆</mo> </mrow> </msup> <mo>=</mo> <mn>116</mn> <mi>f</mi> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>Y</mi> <msub> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">n</mi> </mrow> </mrow> </msub> </mfrac> </mrow> <mo>)</mo> </mrow> <mo>−</mo> <mn>16.</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle L^{\star }=116f\left({\frac {Y}{Y_{\mathrm {n} }}}\right)-16.}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1fb6a5e3c47a9f01e9fc26bd7af0e135ed7a90d7" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:23.455ex; height:6.176ex;" alt="{\displaystyle L^{\star }=116f\left({\frac {Y}{Y_{\mathrm {n} }}}\right)-16.}"></noscript><span class="lazy-image-placeholder" style="width: 23.455ex;height: 6.176ex;vertical-align: -2.505ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1fb6a5e3c47a9f01e9fc26bd7af0e135ed7a90d7" data-alt="{\displaystyle L^{\star }=116f\left({\frac {Y}{Y_{\mathrm {n} }}}\right)-16.}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <p>At first glance, you might approximate the lightness function by a cube root, an approximation that is found in much of the technical literature. However, the linear segment near black is significant, and so the 116 and 16 coefficients. The best-fit pure power function has an exponent of about 0.42, far from <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num">1</span><span class="sr-only">/</span><span class="den">3</span></span>⁠</span>.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> An approximately 18% <a href="/wiki/Grey_card" class="mw-redirect" title="Grey card">grey card</a>, having an exact reflectance of (<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num">33</span><span class="sr-only">/</span><span class="den">58</span></span>⁠</span>)<sup>3</sup>, has a lightness value of 50. It is called "<a href="/wiki/Middle_gray" title="Middle gray">mid grey</a>" because its lightness is midway between black and white. </p> <div class="mw-heading mw-heading3"><h3 id="1997">1997</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=12" title="Edit section: 1997" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p>As early as in 1967 a hyperbolic relationship between light intensity and cone cell responses was discovered in fish, in line with the <a href="/wiki/Michaelis%E2%80%93Menten_kinetics" title="Michaelis–Menten kinetics">Michaelis–Menten kinetics</a> model of biochemical reactions.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> In the 70s the same relationship was found in a number of other vertebrates and in 1982, using microelectrodes to measure cone responses in living rhesus macaques, Valeton and Van Norren found the following relationship:<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> </p> <dl><dd>1 / V ~ 1 + (σ / I)<sup>0.74</sup></dd></dl> <p>where V is the measured potential, I the light intensity and σ a constant. In 1986 Seim and Valberg realised that this relationship might aid in the construction of a more uniform colour space.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> This inspired advances in colour modelling and when the <a href="/wiki/International_Commission_on_Illumination" title="International Commission on Illumination">International Commission on Illumination</a> held a symposium in 1996, objectives for a new standard colour model were formulated and in 1997 <a href="/wiki/CIECAM97s" class="mw-redirect" title="CIECAM97s">CIECAM97s</a> (International Commission on Illumination, colour appearance model, 1997, simple version) was standardised.<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> CIECAM97s distinguishes between lightness, how light something appears compared to a similarly lit white object, and brightness, how much light appears to shine from something.<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> According to CIECAM97s the lightness of a sample is: </p> <dl><dd>J = 100 (A<sub>sample</sub> / A<sub>white</sub>)<sup>cz</sup></dd></dl> <p>In this formula, for a small sample under bright conditions in a surrounding field with a relative luminance n compared to white, c has been chosen such that: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\text{cz}}={\frac {1+{\sqrt {n}}}{1+{\sqrt {\frac {1}{5}}}}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mtext>cz</mtext> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mn>1</mn> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mi>n</mi> </msqrt> </mrow> </mrow> <mrow> <mn>1</mn> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mfrac> <mn>1</mn> <mn>5</mn> </mfrac> </msqrt> </mrow> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\text{cz}}={\frac {1+{\sqrt {n}}}{1+{\sqrt {\frac {1}{5}}}}}}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/03b5f10ae17470bcaab11061fdf43705fcae8157" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -4.671ex; width:13.984ex; height:8.676ex;" alt="{\displaystyle {\text{cz}}={\frac {1+{\sqrt {n}}}{1+{\sqrt {\frac {1}{5}}}}}}"></noscript><span class="lazy-image-placeholder" style="width: 13.984ex;height: 8.676ex;vertical-align: -4.671ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/03b5f10ae17470bcaab11061fdf43705fcae8157" data-alt="{\displaystyle {\text{cz}}={\frac {1+{\sqrt {n}}}{1+{\sqrt {\frac {1}{5}}}}}}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <p>This models that a sample will appear darker on a light background than on a dark background. See <a href="/wiki/Contrast_effect" title="Contrast effect">contrast effect</a> for more information on the topic. When n = <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num">1</span><span class="sr-only">/</span><span class="den">5</span></span>⁠</span>, cz = 1, representing the assumption that most scenes have an average relative luminance of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num">1</span><span class="sr-only">/</span><span class="den">5</span></span>⁠</span> compared to bright white, and that therefore a sample in such a surround should be perceived at its proper lightness. The quantity A models the achromatic cone response; it is colour dependent but for a grey sample under bright conditions it works out as: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {\text{A}}{{\text{N}}_{\text{bb}}}}={\frac {122}{1+2{\Bigl (}{\tfrac {1}{10}}Y{\sqrt[{3}]{5L_{A}}}{\Bigr )}^{-0.73}}}+1}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mtext>A</mtext> <msub> <mrow class="MJX-TeXAtom-ORD"> <mtext>N</mtext> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mtext>bb</mtext> </mrow> </msub> </mfrac> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>122</mn> <mrow> <mn>1</mn> <mo>+</mo> <mn>2</mn> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.623em" minsize="1.623em">(</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <mn>1</mn> <mn>10</mn> </mfrac> </mstyle> </mrow> <mi>Y</mi> <mrow class="MJX-TeXAtom-ORD"> <mroot> <mrow> <mn>5</mn> <msub> <mi>L</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </mroot> </mrow> <msup> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.623em" minsize="1.623em">)</mo> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo>−</mo> <mn>0.73</mn> </mrow> </msup> </mrow> </mfrac> </mrow> <mo>+</mo> <mn>1</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\frac {\text{A}}{{\text{N}}_{\text{bb}}}}={\frac {122}{1+2{\Bigl (}{\tfrac {1}{10}}Y{\sqrt[{3}]{5L_{A}}}{\Bigr )}^{-0.73}}}+1}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f73b82bc530da0b5bf3b5e0a3e2ea02f6a1b22f4" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -5.005ex; width:35.739ex; height:8.509ex;" alt="{\displaystyle {\frac {\text{A}}{{\text{N}}_{\text{bb}}}}={\frac {122}{1+2{\Bigl (}{\tfrac {1}{10}}Y{\sqrt[{3}]{5L_{A}}}{\Bigr )}^{-0.73}}}+1}"></noscript><span class="lazy-image-placeholder" style="width: 35.739ex;height: 8.509ex;vertical-align: -5.005ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f73b82bc530da0b5bf3b5e0a3e2ea02f6a1b22f4" data-alt="{\displaystyle {\frac {\text{A}}{{\text{N}}_{\text{bb}}}}={\frac {122}{1+2{\Bigl (}{\tfrac {1}{10}}Y{\sqrt[{3}]{5L_{A}}}{\Bigr )}^{-0.73}}}+1}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <dl><dd><small>N<sub>bb</sub> is a fudge factor that is normally 1; it's only of concern when comparing brightness judgements based on slightly different reference whites.</small></dd></dl> <p>Here Y is the relative luminance compared to white on a scale of 0 to 1 and L<sub>A</sub> is the average luminance of the adapting visual field as a whole, measured in <a href="/wiki/Candela_per_square_metre" title="Candela per square metre">cd/m<sup>2</sup></a>. The achromatic response follows a kind of <a href="/wiki/Sigmoid_function" title="Sigmoid function">S-curve</a>, ranging from 1 to 123, numbers which follow from the way the cone responses are averaged and which are ultimately based on a rough estimate for the useful range of nerve impulses per second, and which has a fairly large intermediate range where it roughly follows a square root curve. The brightness according to CIECAM97s is then: </p> <dl><dd>Q = (1.24 / c) (J / 100)<sup>0.67</sup> (A<sub>white</sub> + 3)<sup>0.9</sup></dd></dl> <p>The factor 1.24 / c is a surround factor that reflects that scenes appear brighter in dark surrounding conditions. Suggestions for a more comprehensive model, CIECAM97C, were also formulated, to take into account several effects at extremely dark or bright conditions, coloured lighting, as well as the <a href="/wiki/Helmholtz%E2%80%93Kohlrausch_effect" title="Helmholtz–Kohlrausch effect">Helmholtz–Kohlrausch effect</a>, where highly chromatic samples appear lighter and brighter in comparison to a neutral grey. To model the latter effect, in CIECAM97C the formula for J is adjusted as follows: </p> <dl><dd>J<sub>HK</sub> = J + (100 – J) (C / 300) |sin(<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035"><span class="sfrac">⁠<span class="tion"><span class="num">1</span><span class="sr-only">/</span><span class="den">2</span></span>⁠</span>h – 45°)|,</dd></dl> <p>where C is the chroma and h the hue angle </p><p>Q is then calculated from J<sub>HK</sub> instead of from J. This formula has the effect of pulling up the lightness and brightness of coloured samples. The larger the chroma, the stronger the effect; for very saturated colours C can be close to 100 or even higher. The absolute sine term has a sharp V-shaped valley with a zero at yellow and a broad plateau in the deep blues.<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> </p> <div class="mw-heading mw-heading3"><h3 id="2002">2002</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=13" title="Edit section: 2002" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p>The achromatic response in CIECAM97s is a weighted addition of cone responses minus 2.05. Since the total noise term adds up to 3.05, this means that A and consequentially J and Q aren't zero for absolute black. To fix this, Li, Luo & Hunt suggested subtracting 3.05 instead, so the scale starts at zero.<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> Although CIECAM97s was a successful model to spur and direct colorimetric research, Fairchild felt that for practical applications some changes were necessary. Those relevant for lightness calculations were to, rather than use several discrete values for the surround factor c, allow for linear interpolation of c and thereby allowing the model to be used under intermediate surround conditions, and to simplify z to remove the special case for large stimuli because he felt it was irrelevant for imaging applications.<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> Based on experimental results, Hunt, Li, Juan and Luo proposed a number of improvements. Relevant for the topic at hand is that they suggested lowering z slightly.<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> Li and Luo found that a colour space based on such a modified CIECAM97s using lightness as one of the coordinates was more perceptually uniform than CIELAB.<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><p>Because of the shape of the cone response S-curve, when the luminance of a colour is reduced, even if its spectral composition remains the same, the different cone responses do not quite change at the same rate with respect to each other. It is plausible therefore that the perceived hue and saturation will change at low luminance levels. But CIECAM97s predicts much larger deviations than are generally thought likely and therefore Hunt, Li and Luo suggested using a cone response curve which approximates a power curve for a much larger range of stimuli, so hue and saturation are better preserved.<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> </p><p>All these proposals, as well as others relating to chromaticity, resulted in a new colour appearance model, CIECAM02. In this model, the formula for lightness remains the same: </p> <dl><dd>J = 100 (A<sub>sample</sub> / A<sub>white</sub>)<sup>cz</sup></dd></dl> <p>But all the quantities that feed into this formula change in some way. The parameter c is now continuously variable as discussed above and z = 1.48 + √n. Although this is higher than z in CIECAM97s, the total effective power factor is very similar because the effective power factor of the achromatic response is much lower: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {\text{A}}{{\text{N}}_{\text{bb}}}}={\frac {1220}{1+{\frac {27.13}{\left({\frac {{\sqrt[{3}]{5{\text{L}}_{\text{A}}}}{\text{Y}}}{10}}\right)^{0.42}}}}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mtext>A</mtext> <msub> <mrow class="MJX-TeXAtom-ORD"> <mtext>N</mtext> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mtext>bb</mtext> </mrow> </msub> </mfrac> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1220</mn> <mrow> <mn>1</mn> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>27.13</mn> <msup> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mroot> <mrow> <mn>5</mn> <msub> <mrow class="MJX-TeXAtom-ORD"> <mtext>L</mtext> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mtext>A</mtext> </mrow> </msub> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </mroot> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mtext>Y</mtext> </mrow> </mrow> <mn>10</mn> </mfrac> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>0.42</mn> </mrow> </msup> </mfrac> </mrow> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\frac {\text{A}}{{\text{N}}_{\text{bb}}}}={\frac {1220}{1+{\frac {27.13}{\left({\frac {{\sqrt[{3}]{5{\text{L}}_{\text{A}}}}{\text{Y}}}{10}}\right)^{0.42}}}}}}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0cf4145052484ea6fe47ab5bb7a3f1a318937696" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -8.671ex; width:24.632ex; height:12.176ex;" alt="{\displaystyle {\frac {\text{A}}{{\text{N}}_{\text{bb}}}}={\frac {1220}{1+{\frac {27.13}{\left({\frac {{\sqrt[{3}]{5{\text{L}}_{\text{A}}}}{\text{Y}}}{10}}\right)^{0.42}}}}}}"></noscript><span class="lazy-image-placeholder" style="width: 24.632ex;height: 12.176ex;vertical-align: -8.671ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0cf4145052484ea6fe47ab5bb7a3f1a318937696" data-alt="{\displaystyle {\frac {\text{A}}{{\text{N}}_{\text{bb}}}}={\frac {1220}{1+{\frac {27.13}{\left({\frac {{\sqrt[{3}]{5{\text{L}}_{\text{A}}}}{\text{Y}}}{10}}\right)^{0.42}}}}}}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <p>As before, this formula assumes bright conditions. Apart from 1220, which results from an arbitrarily assumed cone response constant, the various constants in CIECAM02 were fitted to experimental data sets. The expression for the brightness has also changed considerably: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Q={\frac {4}{c}}{\frac {\sqrt {J}}{10}}(A_{white}+4)\left({\frac {\sqrt[{3}]{5L_{A}}}{10}}\right)^{0.25}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Q</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>4</mn> <mi>c</mi> </mfrac> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <msqrt> <mi>J</mi> </msqrt> <mn>10</mn> </mfrac> </mrow> <mo stretchy="false">(</mo> <msub> <mi>A</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>w</mi> <mi>h</mi> <mi>i</mi> <mi>t</mi> <mi>e</mi> </mrow> </msub> <mo>+</mo> <mn>4</mn> <mo stretchy="false">)</mo> <msup> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mroot> <mrow> <mn>5</mn> <msub> <mi>L</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </mroot> <mn>10</mn> </mfrac> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>0.25</mn> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Q={\frac {4}{c}}{\frac {\sqrt {J}}{10}}(A_{white}+4)\left({\frac {\sqrt[{3}]{5L_{A}}}{10}}\right)^{0.25}}</annotation> </semantics> </math></span><noscript><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/056297984b21edb0145f2cb2323e8843f290972a" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -3.171ex; width:37.224ex; height:8.009ex;" alt="{\displaystyle Q={\frac {4}{c}}{\frac {\sqrt {J}}{10}}(A_{white}+4)\left({\frac {\sqrt[{3}]{5L_{A}}}{10}}\right)^{0.25}}"></noscript><span class="lazy-image-placeholder" style="width: 37.224ex;height: 8.009ex;vertical-align: -3.171ex;" data-src="https://wikimedia.org/api/rest_v1/media/math/render/svg/056297984b21edb0145f2cb2323e8843f290972a" data-alt="{\displaystyle Q={\frac {4}{c}}{\frac {\sqrt {J}}{10}}(A_{white}+4)\left({\frac {\sqrt[{3}]{5L_{A}}}{10}}\right)^{0.25}}" data-class="mwe-math-fallback-image-inline mw-invert skin-invert"> </span></span></dd></dl> <p>Note that contrary to the suggestion from CIECAM97C, CIECAM02 contains no provision for the Helmholtz–Kohlrausch effect.<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><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> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(3)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Other_psychological_effects">Other psychological effects</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=14" title="Edit section: Other psychological effects" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-3 collapsible-block" id="mf-section-3"> <p>This subjective perception of luminance in a non-linear fashion is one thing that makes <a href="/wiki/Gamma_correction" title="Gamma correction">gamma compression</a> of images worthwhile. Beside this phenomenon there are other effects involving perception of lightness. Chromaticity can affect perceived lightness as described by the <a href="/wiki/Helmholtz%E2%80%93Kohlrausch_effect" title="Helmholtz–Kohlrausch effect">Helmholtz–Kohlrausch effect</a>. Though the CIELAB space and relatives do not account for this effect on lightness, it may be implied in the Munsell color model. Light levels may also affect perceived chromaticity, as with the <a href="/wiki/Purkinje_effect" title="Purkinje effect">Purkinje effect</a>. </p> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(4)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="See_also">See also</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=15" title="Edit section: See also" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-4 collapsible-block" id="mf-section-4"> <ul><li><a href="/wiki/Brightness" title="Brightness">Brightness</a></li> <li><a href="/wiki/Tint,_shade_and_tone" title="Tint, shade and tone">Tint, shade and tone</a></li></ul> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(5)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="References">References</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=16" title="Edit section: References" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-5 collapsible-block" id="mf-section-5"> <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-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text">Most of the disadvantages below are listed in <i>A Technical Introduction to Digital Video</i> (1996) by <a href="/wiki/Charles_Poynton" title="Charles Poynton">Charles Poynton</a>, though as mere statements, without examples.</span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></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="CITEREFKuehni2002" class="citation journal cs1">Kuehni, Rolf G. (February 2002). "The early development of the Munsell system". <i>Color Research & Application</i>. <b>27</b> (1): 20–27. <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%2Fcol.10002">10.1002/col.10002</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Color+Research+%26+Application&rft.atitle=The+early+development+of+the+Munsell+system&rft.volume=27&rft.issue=1&rft.pages=20-27&rft.date=2002-02&rft_id=info%3Adoi%2F10.1002%2Fcol.10002&rft.aulast=Kuehni&rft.aufirst=Rolf+G.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHunt1957" class="citation journal cs1">Hunt, Robert W. G. (May 18, 1957). <a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F1791026a0">"Light Energy and Brightness Sensation"</a>. <i>Nature</i>. <b>179</b> (4568): 1026. <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/1957Natur.179Q1026H">1957Natur.179Q1026H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F1791026a0">10.1038/1791026a0</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/13430776">13430776</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Light+Energy+and+Brightness+Sensation&rft.volume=179&rft.issue=4568&rft.pages=1026&rft.date=1957-05-18&rft_id=info%3Apmid%2F13430776&rft_id=info%3Adoi%2F10.1038%2F1791026a0&rft_id=info%3Abibcode%2F1957Natur.179Q1026H&rft.aulast=Hunt&rft.aufirst=Robert+W.+G.&rft_id=https%3A%2F%2Fdoi.org%2F10.1038%252F1791026a0&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span></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="CITEREFValberg2006" class="citation book cs1">Valberg, Arne (2006). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=hNDS1C6x0WYC&q=0.975+OR+97.5+%22magnesium+oxide%22&pg=PA200"><i>Light Vision Color</i></a>. John Wiley and Sons. p. 200. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0470849026" title="Special:BookSources/978-0470849026"><bdi>978-0470849026</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Light+Vision+Color&rft.pages=200&rft.pub=John+Wiley+and+Sons&rft.date=2006&rft.isbn=978-0470849026&rft.aulast=Valberg&rft.aufirst=Arne&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DhNDS1C6x0WYC%26q%3D0.975%2BOR%2B97.5%2B%2522magnesium%2Boxide%2522%26pg%3DPA200&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPriestGibsonMcNicholas1920" class="citation journal cs1">Priest, Irwin G.; Gibson, K.S.; McNicholas, H.J. (September 1920). "An examination of the Munsell color system. I: Spectral and total reflection and the Munsell scale of Value". <i>Technical Paper 167</i> (3). United States Bureau of Standards: 27.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Technical+Paper+167&rft.atitle=An+examination+of+the+Munsell+color+system.+I%3A+Spectral+and+total+reflection+and+the+Munsell+scale+of+Value&rft.issue=3&rft.pages=27&rft.date=1920-09&rft.aulast=Priest&rft.aufirst=Irwin+G.&rft.au=Gibson%2C+K.S.&rft.au=McNicholas%2C+H.J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMunsellSloan,_L.L.Godlove,_I.H.1933" class="citation journal cs1">Munsell, A.E.O.; Sloan, L.L.; Godlove, I.H. (November 1933). "Neutral value scales. I. Munsell neutral value scale". <i><a href="/wiki/JOSA" class="mw-redirect" title="JOSA">JOSA</a></i>. <b>23</b> (11): 394–411. <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/1933JOSA...23..394M">1933JOSA...23..394M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1364%2FJOSA.23.000394">10.1364/JOSA.23.000394</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=JOSA&rft.atitle=Neutral+value+scales.+I.+Munsell+neutral+value+scale&rft.volume=23&rft.issue=11&rft.pages=394-411&rft.date=1933-11&rft_id=info%3Adoi%2F10.1364%2FJOSA.23.000394&rft_id=info%3Abibcode%2F1933JOSA...23..394M&rft.aulast=Munsell&rft.aufirst=A.E.O.&rft.au=Sloan%2C+L.L.&rft.au=Godlove%2C+I.H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span> <i>Note:</i> This paper contains a historical survey stretching to 1760.</span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMunsellSloan,_L.L.Godlove,_I.H.1933" class="citation journal cs1">Munsell, A.E.O.; <a href="/wiki/Louise_L._Sloan" title="Louise L. Sloan">Sloan, L.L.</a>; Godlove, I.H. (December 1933). "Neutral value scales. II. A comparison of results and equations describing value scales". <i><a href="/wiki/JOSA" class="mw-redirect" title="JOSA">JOSA</a></i>. <b>23</b> (12): 419–425. <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/1933JOSA...23..419G">1933JOSA...23..419G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1364%2FJOSA.23.000419">10.1364/JOSA.23.000419</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=JOSA&rft.atitle=Neutral+value+scales.+II.+A+comparison+of+results+and+equations+describing+value+scales&rft.volume=23&rft.issue=12&rft.pages=419-425&rft.date=1933-12&rft_id=info%3Adoi%2F10.1364%2FJOSA.23.000419&rft_id=info%3Abibcode%2F1933JOSA...23..419G&rft.aulast=Munsell&rft.aufirst=A.E.O.&rft.au=Sloan%2C+L.L.&rft.au=Godlove%2C+I.H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNewhallNickerson,_DorothyJudd,_Deane_B1943" class="citation journal cs1">Newhall, Sidney M.; Nickerson, Dorothy; Judd, Deane B (May 1943). "Final report of the O.S.A. subcommittee on the spacing of the Munsell colors". <i>Journal of the Optical Society of America</i>. <b>33</b> (7): 385–418. <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/1943JOSA...33..385N">1943JOSA...33..385N</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1364%2FJOSA.33.000385">10.1364/JOSA.33.000385</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+the+Optical+Society+of+America&rft.atitle=Final+report+of+the+O.S.A.+subcommittee+on+the+spacing+of+the+Munsell+colors&rft.volume=33&rft.issue=7&rft.pages=385-418&rft.date=1943-05&rft_id=info%3Adoi%2F10.1364%2FJOSA.33.000385&rft_id=info%3Abibcode%2F1943JOSA...33..385N&rft.aulast=Newhall&rft.aufirst=Sidney+M.&rft.au=Nickerson%2C+Dorothy&rft.au=Judd%2C+Deane+B&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" 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="CITEREFMoonSpencer,_Domina_Eberle1943" class="citation journal cs1">Moon, Parry; Spencer, Domina Eberle (May 1943). "Metric based on the composite color stimulus". <i><a href="/wiki/JOSA" class="mw-redirect" title="JOSA">JOSA</a></i>. <b>33</b> (5): 270–277. <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/1943JOSA...33..270M">1943JOSA...33..270M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1364%2FJOSA.33.000270">10.1364/JOSA.33.000270</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=JOSA&rft.atitle=Metric+based+on+the+composite+color+stimulus&rft.volume=33&rft.issue=5&rft.pages=270-277&rft.date=1943-05&rft_id=info%3Adoi%2F10.1364%2FJOSA.33.000270&rft_id=info%3Abibcode%2F1943JOSA...33..270M&rft.aulast=Moon&rft.aufirst=Parry&rft.au=Spencer%2C+Domina+Eberle&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSaundersonMilner,_B.I.1944" class="citation journal cs1">Saunderson, Jason L.; Milner, B.I. (March 1944). "Further study of ω space". <i><a href="/wiki/JOSA" class="mw-redirect" title="JOSA">JOSA</a></i>. <b>34</b> (3): 167–173. <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/1944JOSA...34..167S">1944JOSA...34..167S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1364%2FJOSA.34.000167">10.1364/JOSA.34.000167</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=JOSA&rft.atitle=Further+study+of+%CF%89+space&rft.volume=34&rft.issue=3&rft.pages=167-173&rft.date=1944-03&rft_id=info%3Adoi%2F10.1364%2FJOSA.34.000167&rft_id=info%3Abibcode%2F1944JOSA...34..167S&rft.aulast=Saunderson&rft.aufirst=Jason+L.&rft.au=Milner%2C+B.I.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHurvichJameson,_Dorothea1957" class="citation journal cs1">Hurvich, Leo M.; Jameson, Dorothea (November 1957). "An Opponent-Process Theory of Color Vision". <i><a href="/wiki/Psychological_Review" title="Psychological Review">Psychological Review</a></i>. <b>64</b> (6): 384–404. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1037%2Fh0041403">10.1037/h0041403</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/13505974">13505974</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:27613265">27613265</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Psychological+Review&rft.atitle=An+Opponent-Process+Theory+of+Color+Vision&rft.volume=64&rft.issue=6&rft.pages=384-404&rft.date=1957-11&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A27613265%23id-name%3DS2CID&rft_id=info%3Apmid%2F13505974&rft_id=info%3Adoi%2F10.1037%2Fh0041403&rft.aulast=Hurvich&rft.aufirst=Leo+M.&rft.au=Jameson%2C+Dorothea&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" 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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJamesonLeo_M._Hurvich1964" class="citation journal cs1">Jameson, Dorothea; Leo M. 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"Empirical relationships with the Munsell Value scale". <i>Proceedings of the Institute of Radio Engineers</i>. <b>43</b> (9): 1137. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FJRPROC.1955.277892">10.1109/JRPROC.1955.277892</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+Institute+of+Radio+Engineers&rft.atitle=Empirical+relationships+with+the+Munsell+Value+scale&rft.volume=43&rft.issue=9&rft.pages=1137&rft.date=1955-09&rft_id=info%3Adoi%2F10.1109%2FJRPROC.1955.277892&rft.aulast=Ladd&rft.aufirst=J.H.&rft.au=Pinney%2C+J.E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" 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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGlasserA.H._McKinneyC.D._ReillyP.D._Schnelle1958" class="citation journal cs1">Glasser, L.G.; A.H. McKinney; C.D. Reilly; P.D. Schnelle (October 1958). "Cube-root color coordinate system". <i><a href="/wiki/JOSA" class="mw-redirect" title="JOSA">JOSA</a></i>. <b>48</b> (10): 736–740. <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/1958JOSA...48..736G">1958JOSA...48..736G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1364%2FJOSA.48.000736">10.1364/JOSA.48.000736</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=JOSA&rft.atitle=Cube-root+color+coordinate+system&rft.volume=48&rft.issue=10&rft.pages=736-740&rft.date=1958-10&rft_id=info%3Adoi%2F10.1364%2FJOSA.48.000736&rft_id=info%3Abibcode%2F1958JOSA...48..736G&rft.aulast=Glasser&rft.aufirst=L.G.&rft.au=A.H.+McKinney&rft.au=C.D.+Reilly&rft.au=P.D.+Schnelle&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span></span> </li> <li id="cite_note-gunter-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-gunter_15-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWyszecki1963" class="citation journal cs1"><a href="/wiki/G%C3%BCnter_Wyszecki" title="Günter Wyszecki">Wyszecki, Günter</a> (November 1963). "Proposal for a New Color-Difference Formula". <i><a href="/wiki/JOSA" class="mw-redirect" title="JOSA">JOSA</a></i>. <b>53</b> (11): 1318–1319. <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/1963JOSA...53.1318W">1963JOSA...53.1318W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1364%2FJOSA.53.001318">10.1364/JOSA.53.001318</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=JOSA&rft.atitle=Proposal+for+a+New+Color-Difference+Formula&rft.volume=53&rft.issue=11&rft.pages=1318-1319&rft.date=1963-11&rft_id=info%3Adoi%2F10.1364%2FJOSA.53.001318&rft_id=info%3Abibcode%2F1963JOSA...53.1318W&rft.aulast=Wyszecki&rft.aufirst=G%C3%BCnter&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span> <i>Note:</i> The asterisks are not used in the paper.</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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPauli1976" class="citation journal cs1">Pauli, Hartmut K.A. (1976). "Proposed extension of the CIE recommendation on "Uniform color spaces, color spaces, and color-difference equations, and metric color terms"<span class="cs1-kern-right"></span>". <i><a href="/wiki/JOSA" class="mw-redirect" title="JOSA">JOSA</a></i>. <b>66</b> (8): 866–867. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1364%2FJOSA.66.000866">10.1364/JOSA.66.000866</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=JOSA&rft.atitle=Proposed+extension+of+the+CIE+recommendation+on+%22Uniform+color+spaces%2C+color+spaces%2C+and+color-difference+equations%2C+and+metric+color+terms%22&rft.volume=66&rft.issue=8&rft.pages=866-867&rft.date=1976&rft_id=info%3Adoi%2F10.1364%2FJOSA.66.000866&rft.aulast=Pauli&rft.aufirst=Hartmut+K.A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span></span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPoyntonFunt2014" class="citation journal cs1">Poynton, Charles; Funt, Brian (February 2014). "Perceptual uniformity in digital image representation and display". <i>Color Research and Application</i>. <b>39</b> (1): 6–15. <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%2Fcol.21768">10.1002/col.21768</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Color+Research+and+Application&rft.atitle=Perceptual+uniformity+in+digital+image+representation+and+display&rft.volume=39&rft.issue=1&rft.pages=6-15&rft.date=2014-02&rft_id=info%3Adoi%2F10.1002%2Fcol.21768&rft.aulast=Poynton&rft.aufirst=Charles&rft.au=Funt%2C+Brian&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALightness" class="Z3988"></span></span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text">Ken-Ichi Naka & William Albert Hugh Rushton: <i>The generation and spread of S-potentials in fish (Cyprinidae)</i></span> </li> <li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text">Jean Mathieu Valeton & Dirk van Norren: <i>Light adaptation of primate cones: An analysis based on extracellular data</i></span> </li> <li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text">Thorstein Seim & Arne Valberg: <i>Towards a uniform color space: A better formula to describe the Munsell and OSA color scales</i></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">Mark D. Fairchild: <i>Color Appearance Models</i> § The CIE Color Appearance Model (1997), CIECAM97s</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">Robert William Gainer Hunt: <i>Some comments on using the CIECAM97s colour-appearance model</i></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">Ming Ronnier Luo & Robert William Gainer Hunt: <i>The structure of the CIE 1997 colour appearance model</i></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">Changjun Li, Ming Ronnier Luo & Robert William Gainer Hunt: <i>A revision of the CIECAM97s model</i></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">Mark D. Fairchild: <i>A revision of CIECAM97s for practical applications</i></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">Robert William Gainer Hunt, Changjun Li, Lu-Yin Grace Juan & Ming Ronnier Luo: <i>Further improvements to CIECAM97s</i> (also cited as <i>Further refinements to CIECAM97s</i>)</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">Changjun Li & Ming Ronnier Luo: <i>A uniform colour space based upon CIECAM97s</i></span> </li> <li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text">Robert William Gainer Hunt, Changjun Li & Ming Ronnier Luo: <i>Dynamic cone response functions for models of colour appearance</i></span> </li> <li id="cite_note-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-29">^</a></b></span> <span class="reference-text">Nathan Moroney, Mark D. Fairchild, Robert William Gainer Hunt, Changjun Li, Ming Ronnier Luo & Todd Newman: <i>The CIECAM02 color appearance model</i></span> </li> <li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20090507184133/colour.org/tc8-01">CIE technical committee: Colour Appearance Models for Color Management Applications</a></span> </li> </ol></div></div> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(6)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="External_links">External links</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Lightness&action=edit&section=17" title="Edit section: External links" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span 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id="p-variants" class="minerva-languages"></ul> <ul class="minerva-languages"><li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Ligheid" title="Ligheid – Afrikaans" lang="af" hreflang="af" data-title="Ligheid" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target"><span>Afrikaans</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%A5%D8%B6%D8%A7%D8%A1%D8%A9_%D8%A7%D9%84%D9%84%D9%88%D9%86" title="إضاءة اللون – Arabic" lang="ar" hreflang="ar" data-title="إضاءة اللون" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%A1%D0%B2%D0%B5%D1%82%D0%BB%D0%B0%D1%82%D0%B0" title="Светлата – Belarusian" lang="be" hreflang="be" data-title="Светлата" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target"><span>Беларуская</span></a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/%D0%A1%D1%8C%D0%B2%D1%8F%D1%82%D0%BB%D1%8B%D0%BD%D1%8F" title="Сьвятлыня – Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="Сьвятлыня" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target"><span>Беларуская (тарашкевіца)</span></a></li><li class="interlanguage-link interwiki-cv mw-list-item"><a href="https://cv.wikipedia.org/wiki/%C3%87%D1%83%D1%82%C4%83%D0%BB%C4%83%D1%85_(%D1%82%C4%95%D1%81)" title="Çутăлăх (тĕс) – Chuvash" lang="cv" hreflang="cv" data-title="Çутăлăх (тĕс)" data-language-autonym="Чӑвашла" data-language-local-name="Chuvash" class="interlanguage-link-target"><span>Чӑвашла</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Helligkeit_(Farbe)" title="Helligkeit (Farbe) – German" lang="de" hreflang="de" data-title="Helligkeit (Farbe)" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Luminosidad_(color)" title="Luminosidad (color) – Spanish" lang="es" hreflang="es" data-title="Luminosidad (color)" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B1%D9%88%D8%B4%D9%86%DB%8C" title="روشنی – Persian" lang="fa" hreflang="fa" data-title="روشنی" 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/Luminosit%C3%A9_(colorim%C3%A9trie)" title="Luminosité (colorimétrie) – French" lang="fr" hreflang="fr" data-title="Luminosité (colorimétrie)" 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/%EB%B0%9D%EA%B8%B0" title="밝기 – Korean" lang="ko" hreflang="ko" data-title="밝기" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Ton_(likovna_umjetnost)" title="Ton (likovna umjetnost) – Croatian" lang="hr" hreflang="hr" data-title="Ton (likovna umjetnost)" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Kebercahayaan" title="Kebercahayaan – Indonesian" lang="id" hreflang="id" data-title="Kebercahayaan" 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-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Tono_(pittura)" title="Tono (pittura) – Italian" lang="it" hreflang="it" data-title="Tono (pittura)" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Spalv%C5%B3_%C5%A1viesumas" title="Spalvų šviesumas – Lithuanian" lang="lt" hreflang="lt" data-title="Spalvų šviesumas" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Intensiteit_(kleur)" title="Intensiteit (kleur) – Dutch" lang="nl" hreflang="nl" data-title="Intensiteit (kleur)" 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/%E6%98%8E%E5%BA%A6" title="明度 – Japanese" lang="ja" hreflang="ja" data-title="明度" 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-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Val%C3%B8r" title="Valør – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Valør" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Luminosidade_(cor)" title="Luminosidade (cor) – Portuguese" lang="pt" hreflang="pt" data-title="Luminosidade (cor)" 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%A1%D0%B2%D0%B5%D1%82%D0%BB%D0%BE%D1%82%D0%B0_(%D1%86%D0%B2%D0%B5%D1%82)" title="Светлота (цвет) – Russian" lang="ru" hreflang="ru" data-title="Светлота (цвет)" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E4%BA%AE%E5%80%BC" title="亮值 – Cantonese" lang="yue" hreflang="yue" data-title="亮值" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target"><span>粵語</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E6%98%8E%E5%BA%A6" title="明度 – Chinese" lang="zh" hreflang="zh" data-title="明度" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li></ul> </section> </div> <div class="minerva-footer-logo"><img src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" alt="Wikipedia" width="120" height="18" style="width: 7.5em; height: 1.125em;"/> </div> <ul id="footer-info" class="footer-info hlist hlist-separated"> <li id="footer-info-lastmod"> This page was last edited on 20 June 2024, at 03:33<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Content is available under <a class="external" rel="nofollow" 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