why does ps->eps conversion reduce line thickness?

[Mark Mackenzie <markm@student.unsw.edu.au>]

I do ps->eps conversions using:

echo -n '\004' | gs -q -dNOPAUSE -sDEVICE=epswrite \
-sOutputFile=box.eps box.ps >/dev/null

using box.ps below. When box.ps is printed, it comes out as a 1mm thick
1" box (quite dark). When box.eps is printed, the lines are very thin 
(perhaps .2mm) and faint. 

This is when printing to a postscript printer hp2100tn. I think if
you are using gs via magicfilter for a non-ps printer, the printout is
ok.

Does anyone know why this is the case? The problem is that when I
my ps files in a latex document most lines are too faint, and the
thickness is varying as if I had an aliasing error.

Using ps2epsi doesn't seem to help either.
I am using gs_5.50-6_i386.deb

Thanks,
Mark.

box.ps - from postscript.tar.gz on the net somewhere.
%!
%% Draws a one square inch box and inch in from the bottom left

/inch {72 mul} def  

newpath                 
1 inch 1 inch moveto    
2 inch 1 inch lineto  
2 inch 2 inch lineto    
1 inch 2 inch lineto   
closepath               
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