Thanks Farmer and Ernst. You have both provided leads to the the kind of fact-based information I was hoping we could include in this thread. Opinions from knowledgeable and experienced people are certainly good, but opinions derived from more rigorous technical studies of the issues are often better.
To respond to the question posed to me by Schewe, I still use the venerable old Gretag Spectrolino/Spectroscan which is too slow to render a verdict on measurable color shift in a good profiling target at the 15 minutes-after-printing-mark since it takes over 1/2 hour to measure several hundred patches, but studies I've done on dye-based systems show that they change significantly for days, even weeks. Pigmented ink prints, on the other hand, from all the major OEMs (HP, Canon, and Epson) have all settled to respectable stability within the time that my Spectroscan can measure a target twice. Moreover, if I take a hot-off-the-printer "wet" print from either Epson or Canon pigment printers in my lab, both have an initial "wet" look that can slightly hinder one's ability to judge final color because even if color shift is negligible, final surface reflectivity (e.g., gloss factor) is not. That said, I've gotten experienced enough to estimate the final "look" after full dry down of pigmented ink sets on most papers that I have no trouble judging whether I've "nailed" the color on a fine art reproduction (I do those for select clients, too) even as the print comes fresh off the printer. Thus, I still don't understand what the practical significance is for others who suggest the Canon pigment systems aren't as good as the Epson.
