Comment 16 for bug 332472

(In reply to comment #7)
> I have to disagree. The benefit is major and immediate. Gecko PS output has
> severe issues at the moment when dealing with transparency. The visual
> impression of printing semi-transparent elements is the following: they get
> rendered to the screen resolution first (text is hinted to the screen
> resolution), then the bitmap is scaled up to 300dpi resolution and so dumped
> into PS. This looks very bad. But even usual 300dpi image fallbacks are
> perceptibly blurry when printed on a 600dpi inkjet printer.

If this is only occurring with PS you may be seeing this bug:

https://bugs.freedesktop.org/show_bug.cgi?id=24692

Can you try testing with cairo master to see if it has been fixed?