Rasterizing picture with gs

[Magnus Paulsson]

I have some problem with rasterizing (dithering) a picture.

This works nicely:
cat foo.ps | gs -sDEVICE=x11mono -r600 -dDITHERPPI=40
and is the result I want! (In other words if you have some
other dithering algorithm that you think is better, do NOT
tell me :-).

However, I want the output in postscript (to print a huge (>3 feet square)
poster in BW):
cat foo.ps | gs -sDEVICE=psmono -r600 -dDITHERPPI=40 -sOutputFile=foo2.ps
gives me a tiny version of the image in the lower left of the page.
(however, the rasterizing is ok, kind of ....., the file size is a bit large)
Is this a bug/feature/idiot in front of the keyboard?

I've tried using pswrite/pdfwrite but they do not accept -dBitsPerPixel=1,
and thus do not rasterize it. (also tried -dCOLORsomething=false/0/1).

Also, tried AFPL gs 7.0/Sun and another (maybe same version) on my Linux box.

Any reply is appreciated but an easy to understand for someone not
really interested in the inner working of gs would be preferred.

Thanks / Magnus