In which forum should I ask Foomatic-related questions?
Forum: LF OpenPrinting Site Support 
What is foomatic?
Foomatic is a system that creates a PPD file from a database.
The PPDs are created by the foomatic-db-engine package, the database resides in the package foomatic-db, and to make the PPDs working with all common printing systems the universal filter foomatic-rip (from the foomatic-filters package) is needed.
What are cupsomatic? lpdomatic? pdqomatic?
These were scripts that connect PPD's to the specific named
spooler. With introduction of Foomatic 3.x the *omatic scripts are unified into a single script
How do I use unprintable margins with gimp-print?
If you are using Gimp-Print 4.3.7, you need to apply the
following two patches to get generation of the "*ImageableArea" lines
in the Foomatic PPD files and to work around a bug in the Gimp-Print
database of printer capabilities:
Margins Patch 
Without the first patch you cannot compile Gimp-Print 4.3.7 at all due
to two files being forgotten to be added to the tarball.
If you use Gimp-Print 4.3.x from CVS, please update from the CVS
again, as my first upload of unprintable margin support was broken.
Also update the CVS of "foomatic-db-engine", I have fixed a small