Troubleshooting poor print quality

[Mike Paul]

I'm using a printer with CUPS which isn't in the Foomatic database (a
Konica KL-3015 color laser, to be specific) and I've configured it by
taking the PPD file shipped with the printer's Windows driver, and adding
the following line in the appropriate place:

  *cupsFilter: "application/vnd.cups-raster 0 rastertohp"

(I want PCL output because this printer doesn't support PostScript.)

Printing from Windows works fine -- the Windows clients (which have the
Windows driver installed) submit jobs directly using IPP and they come out
looking as I'd expect.  But when I try to print things using the "lp"
command I get very poor-quality results; a plain-text file comes out
looking like a fax, very low-resolution and with gaps in some letters (the
left side of the loops in the letters 'p' and 'b' arent' closed).

I want to troubleshoot this, but I'm not sure where to start.  I know the
text is going through some filters and getting rasterized by CUPS, because
the printer can print plain text just fine if it's sent raw; I
believe the filter chain is (texttops -> pstoraster -> rastertohp) but I
haven't been able to find any way to actually see what CUPS is doing as it
processes the job, or look at the intermediate stages of output.

I'm not concerned right now with the various settings in the PPD file for
things like paper trays; I just want to get a look at what's happening to
my job as it makes its way through CUPS processing.  Is there a way to do
this?

(I should note that I'm not looking for a solution which just passes plain
text straight through; I do print PostScript and graphics from time to
time, and need working filtering for these.)
-- 

Mike Paul
mbp2 at lehigh.edu
http://www.lehigh.edu/~mbp2/