Digital BW, The Print

Hi Folks --

I've been lurking here quite a while, but decided to try and verify
something with anyone else who may be using a Linux / Epson R1800
combination along with Premium Luster paper.  I searched the archives,
but couldn't find any relevant posts.

Just to get a couple of things out of the way, I tried getting a nice
"glossy" look with the standard UC inks and Windows Epson driver - no
dice.  Either a magenta or green cast, and significant bronzing. 
Tried the new QTR with "Premium Luster" settings and while the color
cast vanished and although it seemed to use the glossy black/GLOP
combination, the bronzing problem remained.  On a whim, since I have a
dual-boot WinXP/Ubuntu Linux system, I tried printing an 8x10 BW image
plus a stepwedge from the GIMP image editor using the Gutenprint/CUPS
Epson driver set to grayscale, gloss black ink, and Premium Luster
paper.  And as they say, viola!  Dead neutral, no color casts, no
bronzing, a nearly perfect stepwedge, and the deep, rich blacks/dmax
associated with the luster paper.

So, am I seeing things, or have the GIMP/Gutenprint developers managed
to deliver a "poor man's B&W RIP" for the Epson 1800?  Has anyone else
tried this or heard of it being done?  Since Ubuntu / GIMP /
Gutenprint are all free for the downlad (along with a somewhat steep
learning curve), is there any other brave soul out there who would
like to try and replicate this approach?  I'd be happy to supply via
email more information about my particular setup, although I can't do
much in the way of handholding for Linux newbies (the Ubuntu forums
are *great* however).

As an afterthought, I know that parts of the Gutenprint system are
used in the Mac printer driver, and that the GIMP is also available
for the Mac -- any Mac users experimented with this?

Cheers,
-- Darrell