title: color conversion error after one page using ghostscript
body: <p>I am using Ghostscript 9.07 to convert a PDF file from color to gray using a batch-script. The script works and converts from color to gray but just for the first page. On every PDF I tried (12 PDFs) the conversion strategy reverts back to leave color unchanged after the first page.</p>
  
  <p>Script:</p>
  
  <pre><code>C:\working-environment\gs9.07\bin\gswin64c -o C:\Test\converted.pdf -sDEVICE=pdfwrite -dLastPage=20 -dColorConversionStrategy=/Gray -dProcessColorModel=/DeviceGray C:\Test\original.pdf
  </code></pre>
  
  <p>Note: I am running the script on a Windows 7 PC as Administrator. The -dLastPage parameter is set because i have very long PDFs (500+ pages).</p>
  
  <p>Error:</p>
  
  <pre><code>Unable to convert color space to Gray. reverting strategy to LeaveColorUnchanged.
  </code></pre>
  
  <p>Note:
  I used the Oracle and Postgress manuals because i want to see the performance too.</p>