[Gimp-user] color proofing / printing -- profiles not applied when printing? gutenprint plugin

[Gary Aitken <gimp dreamchaser org>]

Hi all,

I recently installed an epson 3880 and am trying to get decent color out of it.
I'm relatively new at this and may have more than one thing wrong.
At the moment I am using the outback photo printer evaluation image as a test,
since it has rather large color bars and swatches to compare:
  http://outbackprint.outbackphoto.com/printinginsights/pi049/essay.html

I have my Color Management preferences set as follows:
  Mode of operation:          Color managed display
  RGB Profile:                sRGB IEC61966-2.1
  CMYK profile:               None
  Monitor profile:            NEW MultiSync LCD 1970NX
  Display rendering intent:   Perceptual
  Print simulation profile:   Epson Stylus Pro 3880_3890 PremiumGlossyPhotoPaper
  Softproof rendering intent: Perceptual
                              Mark out of gamut colors
  File Open behaviour:        Ask what to do

The test image has an embedded profile, "ProPhoto RGB", which I chose to keep
when I loaded it in.  It shows under "Image"/"Image Properties"/"Color Profile"
as "ProPhoto RGB   Reference Output Medium Metric(ROMM).  I don't know what
the "Reference Output Medium Metric" means...

With color management disabled in the display filters dialog
  ("View"/"Display Filters"/"Color Display Filters")
the image on-screen appears darker and less saturated, with reds too orange
and blues too violet.

With color management enabled the image looks bright and highly saturated,
although the saturated green-yellow and green patches become difficult to 
distinguish.  I suspect that is an out-of-gamut situation, but not sure.
The photographic images in the test image become much brighter and
saturated.

If I also enable "Color Proof", things get muted a bit, particularly in the
test patches, although changes in the actual photographic images on-screen
are much more subtle.

Questions related to viewing on the display:
Assuming the incoming image is "correct" with its attached color profile:

1. Checking only "Color Management"
     Is this "the best / most accurate we can do on this display"?
2. Checking only "Color Proof"
     What does this represent?  Is it a rendering of the image mapped to
     RGB and then color-corrected for the printer, and therefore incorrect?
     Is any display color-correction included in this?
3. Checking both "Color Management" and "Color Proof"
     Is this the proper way to preview an image for printing?
4. This dialog is labelled "Display Filters".  I am assuming that means
   items selected here *only* affect how the display appears, and has 
   nothing to do with printing.  Correct?

The images being printed appear similar to what I see on the screen with
"Color Management" unchecked, and "Color Proof" unchecked:
  When printed, the most saturated reds appear dull and orangeish
  The image has three saturated greens, clearly distinguished in unmanaged
  mode on-screen, but with two of them difficult to distinguish in managed 
  mode on-screen.  The prints have the clearly distinguishable green
  pattern seen in the unmanaged image on-screen.
  In unmanaged mode on-screen, the blues tend towards violet, which is
  what they do when printed.
  CMY are all less saturated unmanaged on-screen, and printed.

In the gutenprint plugin, the printer command being issued is
  lp -s -d 'Epson_Stylus_Pro_3880' -oraw

I also have the test image from Cone Color
  http://shopping.netsuite.com/c.362672/site/test-image.zip
and the two test prints they supply which are supposed to be color-corrected
and should match epson inks very closely.
If I use the Cone Color test image and compare the output to the sample 
cone-color k3 ink sample, there is clearly too much yellow in the skin-tones.

Any help / hints would be greatly appreciated.

Thanks,

Gary