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  6.     <title>8.17.¬† Newsprint</title>
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  20.         <tr>
  21.           <th colspan="3" align="center">8.17.¬†
  22.     <span lang="en" xml:lang="en">Newsprint</span>
  23.   </th>
  24.         </tr>
  25.         <tr>
  26.           <td width="20%" align="left"><a accesskey="p" href="plug-in-ripple.html"><img src="../images/prev.png" alt="Prev" /></a>¬†</td>
  27.           <th width="60%" align="center">8.¬†
  28.     <span lang="en" xml:lang="en">Distort Filters</span>
  29.   </th>
  30.           <td width="20%" align="right">¬†<a accesskey="n" href="plug-in-whirl-pinch.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="plug-in-newsprint"></a>8.17.¬†
  40.     <span lang="en" xml:lang="en">Newsprint</span>
  41.   </h3>
  42.           </div>
  43.         </div>
  44.       </div>
  45.       <a id="id2755572" class="indexterm"></a>
  46.       <a id="id2755590" class="indexterm"></a>
  47.       <div class="sect3" lang="en" xml:lang="en">
  48.         <div class="titlepage">
  49.           <div>
  50.             <div>
  51.               <h4 class="title"><a id="id2755598"></a>8.17.1.¬†
  52.       <span lang="en" xml:lang="en">Overview</span>
  53.     </h4>
  54.             </div>
  55.           </div>
  56.         </div>
  57.         <div class="figure">
  58.           <a id="id2755609"></a>
  59.           <p class="title">
  60.             <b>Figure¬†16.149.¬†
  61.         <span lang="en" xml:lang="en">
  62.           Applying example for the Newsprint filter
  63.         </span>
  64.       </b>
  65.           </p>
  66.           <div class="figure-contents">
  67.             <div class="mediaobject">
  68.               <img src="../images/filters/examples/taj_orig.jpg" alt="Applying example for the Newsprint filter" />
  69.               <div class="caption">
  70.                 <p>Original image</p>
  71.               </div>
  72.             </div>
  73.             <div class="mediaobject">
  74.               <img src="../images/filters/examples/distort-taj-newsprint.jpg" alt="Applying example for the Newsprint filter" />
  75.               <div class="caption">
  76.                 <p>Filter ‚Äú<span class="quote">Newsprint</span>‚Äù applied</p>
  77.               </div>
  78.             </div>
  79.           </div>
  80.         </div>
  81.         <br class="figure-break" />
  82.         <p>
  83.       You can find this filter through
  84.       <span class="guimenu">Filters</span> ‚Üí <span class="guisubmenu">Distorts</span> ‚Üí <span class="guimenuitem">Newsprint</span>.
  85.     </p>
  86.         <p>
  87.       This filter halftones the image using a clustered-dot dither. Halftoning
  88.       is the process of rendering an image with multiple levels of grey or
  89.       colour (i.e. a continuous tone image) on a device with fewer tones;
  90.       often a bi-level device such as a printer or typesetter.
  91.     </p>
  92.         <p>
  93.       The basic premise is to trade off resolution for greater apparent tone
  94.       depth (this is known as spatial dithering).
  95.     </p>
  96.         <p>
  97.       There are many approaches to this, the simplest of which is to throw
  98.       away the low-order bits of tone information; this is what the posterize
  99.       filter does. Unfortunately, the results don't look too good. However, no
  100.       spatial resolution is lost.
  101.     </p>
  102.         <p>
  103.       This filter uses a clustered-dot ordered dither, which reduces the
  104.       resolution of the image by converting cells into spots which grow or
  105.       shrink according to the intensity that cell needs to represent.
  106.     </p>
  107.         <p>
  108.       Imagine a grid super-imposed on the original image.  The image is
  109.       divided into cells by the grid - each cell will ultimately hold a single
  110.       spot made up of multiple output pixels in order to approximate the
  111.       darkness of the original image in that cell.
  112.     </p>
  113.         <p>
  114.       Obviously, a large cell size results in a heavy loss in resolution! The
  115.       spots in the cells typically start off as circles, and grow to be
  116.       diamond shaped. This change in shape is controlled by a <span class="guilabel">spot
  117.       function</span>. By using different spot functions, the evolution
  118.       in the shape of the spots as the cell goes from fully black to fully
  119.       white may be controlled.
  120.     </p>
  121.       </div>
  122.       <div class="sect3" lang="en" xml:lang="en">
  123.         <div class="titlepage">
  124.           <div>
  125.             <div>
  126.               <h4 class="title"><a id="id2755772"></a>8.17.2.¬†
  127.       <span lang="en" xml:lang="en">Options</span>
  128.     </h4>
  129.             </div>
  130.           </div>
  131.         </div>
  132.         <div class="figure">
  133.           <a id="id2755783"></a>
  134.           <p class="title">
  135.             <b>Figure¬†16.150.¬†
  136.         <span lang="en" xml:lang="en">
  137.             ‚Äú<span class="quote">Newsprint</span>‚Äù filter options
  138.         </span>
  139.       </b>
  140.           </p>
  141.           <div class="figure-contents">
  142.             <div class="mediaobject">
  143.               <img src="../images/filters/filters-distort-newsprint.png" alt="Newsprint filter options" />
  144.             </div>
  145.           </div>
  146.         </div>
  147.         <br class="figure-break" />
  148.         <div class="variablelist">
  149.           <dl>
  150.             <dt>
  151.               <span class="term">Preview</span>
  152.             </dt>
  153.             <dd>
  154.               <p>
  155.             All your setting changes will appear in the Preview without
  156.             affecting the image until you click on <span class="guilabel">OK</span>.
  157.             Note that the preview displays the whole image, even if the
  158.             final result will concern a selection. Don't keep
  159.             <span class="emphasis"><em>Do Preview</em></span> checked if your computer is too
  160.             much slow.
  161.           </p>
  162.             </dd>
  163.             <dt>
  164.               <span class="term">Resolution</span>
  165.             </dt>
  166.             <dd>
  167.               <p>
  168.             This group controls the cell size, either by setting the input and
  169.             output resolutions, or directly.
  170.           </p>
  171.               <div class="variablelist">
  172.                 <dl>
  173.                   <dt>
  174.                     <span class="term">Input SPI</span>
  175.                   </dt>
  176.                   <dd>
  177.                     <p>
  178.                   <span class="guilabel">Input SPI</span>
  179.                   : Resolution of the original input image, in Samples Per
  180.                   Inch (SPI). This is automatically initialised to the input
  181.                   image's resolution.
  182.                 </p>
  183.                   </dd>
  184.                   <dt>
  185.                     <span class="term">Output LPI</span>
  186.                   </dt>
  187.                   <dd>
  188.                     <p>
  189.                   <span class="guilabel">Output LPI</span>: Desired output
  190.                   resolution, in Lines Per Inch (LPI).
  191.                 </p>
  192.                   </dd>
  193.                   <dt>
  194.                     <span class="term">Cell Size</span>
  195.                   </dt>
  196.                   <dd>
  197.                     <p>
  198.                   <span class="guilabel">Cell Size</span>: Resulting cell size, in
  199.                   pixels.  Most often you will want to set this directly.
  200.                 </p>
  201.                   </dd>
  202.                 </dl>
  203.               </div>
  204.             </dd>
  205.             <dt>
  206.               <span class="term">Screen</span>
  207.             </dt>
  208.             <dd>
  209.               <div class="variablelist">
  210.                 <dl>
  211.                   <dt>
  212.                     <span class="term">Separate To RGB, CMYK, Intensity</span>
  213.                   </dt>
  214.                   <dd>
  215.                     <p>
  216.                   <span class="guilabel">Separate To RGB, CMYK, Intensity</span>:
  217.                   Select which colorspace you
  218.                   wish to operate in.  In <span class="emphasis"><em>RGB</em></span> mode, no
  219.                   colorspace conversion is performed. In
  220.                   <span class="emphasis"><em>CMYK</em></span>, the image is first
  221.                   internally converted to CMYK, then each colour channel is
  222.                   separately halftoned, before finally being
  223.                   recombined back to an RGB image.
  224.                   In <span class="emphasis"><em>Intensity</em></span> mode, the
  225.                   image is internally converted to grayscale,
  226.                   halftoned, then the result used as the alpha channel
  227.                   for the input image.  This is good for special
  228.                   effects, but requires a little experimentation to
  229.                   achieve best results.  Hint: try CMYK if you don't know
  230.                   which to go for initially.
  231.                 </p>
  232.                   </dd>
  233.                   <dt>
  234.                     <span class="term">Black Pullout (%)</span>
  235.                   </dt>
  236.                   <dd>
  237.                     <p>
  238.                   <span class="guilabel">Black Pullout (%)</span> When doing
  239.                   RGB->CMYK conversion, how much K (black) should be used?
  240.                 </p>
  241.                   </dd>
  242.                   <dt>
  243.                     <span class="term">Lock Channels</span>
  244.                   </dt>
  245.                   <dd>
  246.                     <p>
  247.                   <span class="guilabel">Lock Channels</span>: Make channel
  248.                   modifications apply to all channels.
  249.                 </p>
  250.                   </dd>
  251.                   <dt>
  252.                     <span class="term">Factory Defaults</span>
  253.                   </dt>
  254.                   <dd>
  255.                     <p>
  256.                   <span class="guilabel">Factory Defaults</span>: Restore the
  257.                   default settings which should give pleasing results.
  258.                 </p>
  259.                   </dd>
  260.                   <dt>
  261.                     <span class="term">Angle</span>
  262.                   </dt>
  263.                   <dd>
  264.                     <p>
  265.                   <span class="guilabel">Angle</span>: Cell grid angle for this
  266.                   channel.
  267.                 </p>
  268.                   </dd>
  269.                   <dt>
  270.                     <span class="term">Spot Function</span>
  271.                   </dt>
  272.                   <dd>
  273.                     <p>
  274.                   <span class="guilabel">Spot Function</span>: Spot function to
  275.                   be used for this channel (see preview in blue cell-boxes).
  276.                 </p>
  277.                   </dd>
  278.                 </dl>
  279.               </div>
  280.             </dd>
  281.             <dt>
  282.               <span class="term">Antialiasing</span>
  283.             </dt>
  284.             <dd>
  285.               <p>
  286.             Proper halftoning does not need antialiasing: the aim is to
  287.             reduce the colour depth after all!  However, since this
  288.             plugin is mainly for special effects, the results are
  289.             displayed on screen rather than by a black/white printer.
  290.             So it is often useful to apply a little anti-aliasing to
  291.             simulate ink smearing on paper.  If you do want to print the
  292.             resulting image then set the antialising to 1 (ie, off).
  293.           </p>
  294.               <div class="variablelist">
  295.                 <dl>
  296.                   <dt>
  297.                     <span class="term">Oversample</span>
  298.                   </dt>
  299.                   <dd>
  300.                     <p>
  301.                   <span class="guilabel">Oversample</span>: Number of subpixels to
  302.                   sample to produce each output pixel.  Set to 1 to disable
  303.                   this feature.  Warning: large numbers here will lead to
  304.                   very long filter runtimes!
  305.                 </p>
  306.                   </dd>
  307.                 </dl>
  308.               </div>
  309.             </dd>
  310.           </dl>
  311.         </div>
  312.       </div>
  313.       <div class="sect3" lang="en" xml:lang="en">
  314.         <div class="titlepage">
  315.           <div>
  316.             <div>
  317.               <h4 class="title"><a id="id2756204"></a>8.17.3.¬†
  318.       <span lang="en" xml:lang="en">Example</span>
  319.     </h4>
  320.             </div>
  321.           </div>
  322.         </div>
  323.         <div class="figure">
  324.           <a id="id2756215"></a>
  325.           <p class="title">
  326.             <b>Figure¬†16.151.¬†
  327.         <span lang="en" xml:lang="en">Example for Newsprint</span>
  328.       </b>
  329.           </p>
  330.           <div class="figure-contents">
  331.             <div class="mediaobject">
  332.               <img src="../images/filters/examples/newsprint.png" alt="Example for Newsprint" />
  333.               <div class="caption">
  334.                 <p>An example from plug-in author</p>
  335.               </div>
  336.             </div>
  337.           </div>
  338.         </div>
  339.         <br class="figure-break" />
  340.       </div>
  341.     </div>
  342.     <div class="navfooter">
  343.       <hr />
  344.       <table width="100%" summary="Navigation footer">
  345.         <tr>
  346.           <td width="40%" align="left"><a accesskey="p" href="plug-in-ripple.html"><img src="../images/prev.png" alt="Prev" /></a>¬†</td>
  347.           <td width="20%" align="center">
  348.             <a accesskey="u" href="filters-distort.html">
  349.               <img src="../images/up.png" alt="Up" />
  350.             </a>
  351.           </td>
  352.           <td width="40%" align="right">¬†<a accesskey="n" href="plug-in-whirl-pinch.html"><img src="../images/next.png" alt="Next" /></a></td>
  353.         </tr>
  354.         <tr>
  355.           <td width="40%" align="left" valign="top"><a accesskey="p" href="plug-in-ripple.html">8.16.¬†
  356.     <span lang="en" xml:lang="en">Ripple</span>
  357.   </a>¬†</td>
  358.           <td width="20%" align="center">
  359.             <a accesskey="h" href="index.html">
  360.               <img src="../images/home.png" alt="Home" />
  361.             </a>
  362.           </td>
  363.           <td width="40%" align="right" valign="top">¬†<a accesskey="n" href="plug-in-whirl-pinch.html">8.18.¬†
  364.     <span lang="en" xml:lang="en">Whirl and Pinch</span>
  365.   </a></td>
  366.         </tr>
  367.       </table>
  368.     </div>
  369.   </body>
  370. </html>
  371.