Photos with green areas when using cups ppd with gimp print on HP 7550

[ij at w3.org]

Hello,

I am trying to print from the gimp to an HP Photosmart 7550.
I have told the gimp to use the ppd supplied by the Debian
package foomatic-filters-ppds (version 20040506-1). On certain
photos, brownish colors are printed (very) green.

I am looking for any help setting up an HP 7550 to print photos
from gimp-print. I have tried other PPD files as well (I think
from cups.

I am having a hard time understanding what needs to be changed
to affect the print quality when printing from the gimp.
Is it a question of the proper PPD file? Is it something else?

All help appreciated,

Thank you,

 _ Ian