I'm printing on a 2400 so I won't presume to speak for the 4800. I can tell you that rag paper profiles created for the 2400 in ICM mode have mucked up shadow tones (particularly greens and browns) that are very similar to what's discussed here: http://www.gamutvision.com/docs/smudged_pines.html
. Using Color Controls mode and the right media type largely eliminates the problem in most cases (but not all).
I can also say that in the case of B/W printing on matte/rag papers, I can get much better linearity and shadow details using custom curves with Quadtone RIP than I can with any approach using the Epson driver, including ABW mode or custom profiles made in ICM or Color Controls mode.
With a high-DMAX paper such as Innova F-Type these issues pretty much go away, but the 2400 driver leaves a lot to be desired when it comes to matte papers.
Jeff, several points here:
(1) I donīt know how it works on the 2400, but the way we use the 4800 with the Epson driver is to select NO COLOR MANAGEMENT in the printer driver, and LET PHOTOSHOP DETERMINE COLORS in Photoshop Print with Preview preferences.
(2) Matte papers are a challenge in the deep dark areas whatever the software. That much said if the Quadtone RIP with a custom profile gives you better results than the driver, perhaps this is something I should look at, as ImagePrint didnīt do it for me.
(3) I agree Innova F-Type is a good way to solve this problem, except that it costs a fortune to switch back and forth on the Epson 4800 (major design flaw), which is why Iīm going to switch either to an HP 9180 or an Epson 3800 once enough time has passed with both on the market to make an informed choice.