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  6.     <title>11.3.¬† Desaturate</title>
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  13.     <link rel="up" href="gimp-imagewindow-menus-colors.html" title="11.¬† The ‚ÄúColors‚Äù Menu" />
  14.     <link rel="prev" href="gimp-imagewindow-menus-colors-tools.html" title="11.2.¬† Colors Tools" />
  15.     <link rel="next" href="gimp-layer-invert.html" title="11.4.¬† Invert" />
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  17.   <body>
  18.     <div class="navheader">
  19.       <table width="100%" summary="Navigation header">
  20.         <tr>
  21.           <th colspan="3" align="center">11.3.¬†
  22.     <span lang="en" xml:lang="en">Desaturate</span>
  23.   </th>
  24.         </tr>
  25.         <tr>
  26.           <td width="20%" align="left"><a accesskey="p" href="gimp-imagewindow-menus-colors-tools.html"><img src="../images/prev.png" alt="Prev" /></a>¬†</td>
  27.           <th width="60%" align="center">11.¬†
  28.     <span lang="en" xml:lang="en">The ‚Äú<span class="quote">Colors</span>‚Äù Menu</span>
  29.   </th>
  30.           <td width="20%" align="right">¬†<a accesskey="n" href="gimp-layer-invert.html"><img src="../images/next.png" alt="Next" /></a></td>
  31.         </tr>
  32.       </table>
  33.       <hr />
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  35.     <div class="sect2" lang="en" xml:lang="en">
  36.       <div class="titlepage">
  37.         <div>
  38.           <div>
  39.             <h3 class="title"><a id="gimp-layer-desaturate"></a>11.3.¬†
  40.     <span lang="en" xml:lang="en">Desaturate</span>
  41.   </h3>
  42.           </div>
  43.           <div>
  44.             <div class="revhistory">
  45.               <table border="1" width="100%" summary="Revision history">
  46.                 <tr>
  47.                   <th align="left" valign="top" colspan="3">
  48.                     <b>Revision History</b>
  49.                   </th>
  50.                 </tr>
  51.                 <tr>
  52.                   <td align="left">Revision $Revision: 2342 $</td>
  53.                   <td align="left">2008-01-21</td>
  54.                   <td align="left">ude</td>
  55.                 </tr>
  56.               </table>
  57.             </div>
  58.           </div>
  59.         </div>
  60.       </div>
  61.       <a id="id2715929" class="indexterm"></a>
  62.       <a id="id2715942" class="indexterm"></a>
  63.       <p>
  64.     By using the <span class="guimenuitem">Desaturate</span> command, you can
  65.     convert all of the colors on the active layer to corresponding shades
  66.     of gray. This differs from converting the image to grayscale in two
  67.     respects. First, it only operates on the active layer and second,
  68.     the colors on the layer are still RGB values with three components. This
  69.     means that you can paint on the layer, or individual parts of it,
  70.     using color at a later time.
  71.   </p>
  72.       <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
  73.         <table border="0" summary="Note">
  74.           <tr>
  75.             <td rowspan="2" align="center" valign="top" width="25">
  76.               <img alt="[Note]" src="../images/note.png" />
  77.             </td>
  78.             <th align="left">Note</th>
  79.           </tr>
  80.           <tr>
  81.             <td align="left" valign="top">
  82.               <p>
  83.       This command only works on layers of RGB images. If the image is in
  84.       Grayscale or Indexed mode, the menu entry is insensitive and
  85.       grayed out.
  86.     </p>
  87.             </td>
  88.           </tr>
  89.         </table>
  90.       </div>
  91.       <div class="sect3" lang="en" xml:lang="en">
  92.         <div class="titlepage">
  93.           <div>
  94.             <div>
  95.               <h4 class="title"><a id="id2715983"></a>11.3.1.¬†
  96.       <span lang="en" xml:lang="en">Activate the Command</span>
  97.     </h4>
  98.             </div>
  99.           </div>
  100.         </div>
  101.         <div class="itemizedlist">
  102.           <ul type="disc">
  103.             <li>
  104.               <p>
  105.           You can access this command from the image menubar through
  106.           <span class="guimenu"><span class="accel">C</span>olors</span> ‚Üí <span class="guimenuitem"><span class="accel">D</span>esaturate</span>.
  107.         </p>
  108.             </li>
  109.           </ul>
  110.         </div>
  111.       </div>
  112.       <div class="sect3" lang="en" xml:lang="en">
  113.         <div class="titlepage">
  114.           <div>
  115.             <div>
  116.               <h4 class="title"><a id="id2716030"></a>11.3.2.¬†
  117.       <span lang="en" xml:lang="en">Options</span>
  118.     </h4>
  119.             </div>
  120.           </div>
  121.         </div>
  122.         <p>
  123.       With GIMP v2.4, a new option dialog appeared:
  124.     </p>
  125.         <div class="figure">
  126.           <a id="id2716049"></a>
  127.           <p class="title">
  128.             <b>Figure¬†15.131.¬†
  129.         <span lang="en" xml:lang="en">The ‚Äú<span class="quote">Desaturate</span>‚Äù option dialog</span>
  130.       </b>
  131.           </p>
  132.           <div class="figure-contents">
  133.             <div class="mediaobject">
  134.               <img src="../images/menus/colors-desaturate.png" alt="The Desaturate option dialog" />
  135.             </div>
  136.           </div>
  137.         </div>
  138.         <br class="figure-break" />
  139.         <p>Three options are available:</p>
  140.         <div class="variablelist">
  141.           <p class="title">
  142.             <b>
  143.         <span lang="en" xml:lang="en">Choose shade of gray based on</span>
  144.       </b>
  145.           </p>
  146.           <dl>
  147.             <dt>
  148.               <span class="term">
  149.           <span lang="en" xml:lang="en">Lightness</span>
  150.         </span>
  151.             </dt>
  152.             <dd>
  153.               <p>The graylevel will be calculated as</p>
  154.               <div class="informalequation">
  155.                 <div class="mediaobject">
  156.                   <span lang="en" xml:lang="en">
  157.                   Lightness = ¬Ω * (max(R,G,B) + min(R,G,B))
  158.                 </span>
  159.                 </div>
  160.               </div>
  161.             </dd>
  162.             <dt>
  163.               <span class="term">
  164.           <span lang="en" xml:lang="en">Luminosity</span>
  165.         </span>
  166.             </dt>
  167.             <dd>
  168.               <p>The graylevel will be calculated as</p>
  169.               <div class="informalequation">
  170.                 <div class="mediaobject">
  171.                   <span lang="en" xml:lang="en">
  172.                   Luminosity = 0.21 * R + 0.71 * G + 0.07 * B
  173.                 </span>
  174.                 </div>
  175.               </div>
  176.             </dd>
  177.             <dt>
  178.               <span class="term">
  179.           <span lang="en" xml:lang="en">Average</span>
  180.         </span>
  181.             </dt>
  182.             <dd>
  183.               <p>The graylevel will be calculated as</p>
  184.               <div class="informalequation">
  185.                 <div class="mediaobject">
  186.                   <span lang="en" xml:lang="en">Average Brightness = (R + G + B) / 3</span>
  187.                 </div>
  188.               </div>
  189.             </dd>
  190.           </dl>
  191.         </div>
  192.         <div class="figure">
  193.           <a id="id2716213"></a>
  194.           <p class="title">
  195.             <b>Figure¬†15.132.¬†
  196.         <span lang="en" xml:lang="en">Comparing the three options</span>
  197.       </b>
  198.           </p>
  199.           <div class="figure-contents">
  200.             <div class="mediaobject">
  201.               <img src="../images/menus/sunflower.png" alt="Comparing the three options" />
  202.               <div class="caption">
  203.                 <p>Original image</p>
  204.               </div>
  205.             </div>
  206.             <div class="mediaobject">
  207.               <img src="../images/menus/colors-desaturate-brightness.png" alt="Comparing the three options" />
  208.               <div class="caption">
  209.                 <p>‚Äú<span class="quote">Lightness</span>‚Äù applied</p>
  210.               </div>
  211.             </div>
  212.             <div class="mediaobject">
  213.               <img src="../images/menus/colors-desaturate-luminosity.png" alt="Comparing the three options" />
  214.               <div class="caption">
  215.                 <p>
  216.             ‚Äú<span class="quote">Luminosity</span>‚Äù applied. The result is brighter.
  217.           </p>
  218.               </div>
  219.             </div>
  220.             <div class="mediaobject">
  221.               <img src="../images/menus/colors-desaturate-average.png" alt="Comparing the three options" />
  222.               <div class="caption">
  223.                 <p>
  224.             ‚Äú<span class="quote">Average</span>‚Äù applied. The result is in between
  225.             Brightness and Luminosity.
  226.           </p>
  227.               </div>
  228.             </div>
  229.           </div>
  230.         </div>
  231.         <br class="figure-break" />
  232.       </div>
  233.     </div>
  234.     <div class="navfooter">
  235.       <hr />
  236.       <table width="100%" summary="Navigation footer">
  237.         <tr>
  238.           <td width="40%" align="left"><a accesskey="p" href="gimp-imagewindow-menus-colors-tools.html"><img src="../images/prev.png" alt="Prev" /></a>¬†</td>
  239.           <td width="20%" align="center">
  240.             <a accesskey="u" href="gimp-imagewindow-menus-colors.html">
  241.               <img src="../images/up.png" alt="Up" />
  242.             </a>
  243.           </td>
  244.           <td width="40%" align="right">¬†<a accesskey="n" href="gimp-layer-invert.html"><img src="../images/next.png" alt="Next" /></a></td>
  245.         </tr>
  246.         <tr>
  247.           <td width="40%" align="left" valign="top"><a accesskey="p" href="gimp-imagewindow-menus-colors-tools.html">11.2.¬†
  248.     <span lang="en" xml:lang="en">Colors Tools</span>
  249.   </a>¬†</td>
  250.           <td width="20%" align="center">
  251.             <a accesskey="h" href="index.html">
  252.               <img src="../images/home.png" alt="Home" />
  253.             </a>
  254.           </td>
  255.           <td width="40%" align="right" valign="top">¬†<a accesskey="n" href="gimp-layer-invert.html">11.4.¬†
  256.     <span lang="en" xml:lang="en">Invert</span>
  257.   </a></td>
  258.         </tr>
  259.       </table>
  260.     </div>
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  262. </html>
  263.