</B> before
processing it with <B>ppmshadow</B>.

<P>Black pixels and pixels with the same color as the image
background don't cast a shadow.  If this causes unintentional
&quot;holes&quot; in the shadow, fill the offending areas with a color
which differs from black or the background by RGB values of 1, which
will be imperceptible to the viewer.  Since the comparison is exact,
the modified areas will now cast shadows.  

<P>The background color of the source image (which is preserved in
the output) is deem