<p>My stomach churns when I see this kind of output.</p>

<p><a href="http://www.freeimagehosting.net/uploads/e1097a5a10.jpg" rel="nofollow noreferrer">http://www.freeimagehosting.net/uploads/e1097a5a10.jpg</a></p>

<p>and this was my command
as suggested by <a href="https://stackoverflow.com/questions/75500/best-way-to-convert-pdf-files-to-tiff-files#221341">Best way to convert pdf files to tiff files</a></p>

<pre><code>gswin32c.exe -q -dNOPAUSE -sDEVICE=tiffg4 -sOutputFile=a.tif a.pdf -c quit
</code></pre>

<p>What am I doing wrong?</p>

<p>(commercial products will not be considered)</p>

tiffg4 is a black&white output device.
You should use tiff24nc or tiff12nc as the output device colour PDFs - see
ghostscript output devices
.
These will be uncompressed but you could put the resulting TIFFs through imagemagick or similar to resave as compressed TIFF.