title: Changing pdf image dpi using gs
body: <p>I am trying to change the dpi of a .pdf image (myPic.pdf) using <code>gs</code> in Linux/Ubuntu 11.10</p>
  
  <p>Here's how I am going about it but I get errors:</p>
  
  <pre><code> gs -q -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -dPDFSETTINGS=/printer \
      -sOutputFile=fileout.pdf \
       myPic.pdf`
  </code></pre>
  
  <p>Here, I am attempting to change the dpi to 300 as per <a href="http://milan.kupcevic.net/ghostscript-ps-pdf/" rel="nofollow noreferrer">this</a></p>
  
  <p>The error that I receive when I try the above command is:</p>
  
  <p><code>**** Unable to open the initial device, quitting.
  </code></p>
  
  <p>What gives?</p>
  
  <h2>Possible solution:</h2>
  
  <p><strong>Check <a href="https://stackoverflow.com/q/11850776/957560">this</a> out.</strong></p>