The Role of
filters may be the most widely used on CUPS
installations. You must be clear that these were not
developed by the CUPS people. They are a third-party add-on to
CUPS. They utilize the traditional Ghostscript devices to render jobs
for CUPS. When troubleshooting, you should know about the
difference. Here the whole rendering process is done in one stage,
inside Ghostscript, using an appropriate device for the target
uses PPDs that are generated from the Foomatic
Printer & Driver Database at Linuxprinting.org.
You can recognize these PPDs from the line calling the
*cupsFilter: "application/vnd.cups-postscript 0 cupsomatic"
You may find this line among the first 40 or so lines of the PPD
file. If you have such a PPD installed, the printer shows up in the
CUPS Web interface with a
the driver description.
is a Perl script that runs
Ghostscript with all the complicated command-line options
autoconstructed from the selected PPD and command line options give to
the print job.
is now deprecated. Its PPDs (especially the first
generation of them, still in heavy use out there) are not meeting the
Adobe specifications. You might also suffer difficulties when you try
to download them with “Point'n'Print” to Windows clients. A better
and more powerful successor is now in a stable beta-version: it is called
. To use
as a filter with CUPS, you need the new type of PPDs, which
have a similar but different line:
*cupsFilter: "application/vnd.cups-postscript 0 foomatic-rip"
The PPD-generating engine at Linuxprinting.org has been revamped.
The new PPDs comply with the Adobe spec. They also provide a
new way to specify different quality levels (hi-res photo, normal
color, grayscale, and draft) with a single click, whereas before you
could have required five or more different selections (media type,
resolution, inktype, and dithering algorithm). There is support for
custom-size media built in. There is support to switch
print options from page to page in the middle of a job. And the
best thing is that the new
foomatic-rip works seamlessly with all
legacy spoolers too (like LPRng, BSD-LPD, PDQ, PPR, and so on), providing
for them access to use PPDs for their printing.