The other really interesting thing that has come out of our extensive testing is how much better the gamut is of the Epson 7900 compared to the Canon IPF6350. Have a look at this gamut plot showing how much better the 7900 performs. And this was a comparison made after extensive testing to find out what the optimal ink loads where for the Canon. The only place the Canon performs slightly better is the purple spectrum.
From the canon wiki:
9/28/10 There is a new page on the Wiki comparing gamuts of Canon 8300 to Epson 9900 on Canson Baryta. The Epson has a slightly larger gamut volume (4.4% larger in Colorthink Pro 3), but a dmax which isn't quite as good (L* of 3.9 for Canon, 4.7 for Epson). The Epson has a larger gamut in the lighter tones, particularly oranges, pinks and reds in the L* range of 60-80, while the Canon wins in the darker tones in blues and purples of L* 10-25. Softproofing of a variety of images with saturated colors showed no difference, except for several images with light, saturated oranges, pinks and reds, where Epson had a modest advantage. However, note that Scott Martin reports seeing better purples and yellows in actual prints, so there are limitations to the gamut comparisons. Click the link to read the details and see an AVI file showing the gamuts at all L* levels, and examples of the softproofing differences noted above.http://canonipf.wikispaces.com/
Add: Another quote direct from Wiki which I think explains things really well
Caveat from Scott Martin:
Different applications certainly calculate gamut volumes differently. We've had a bunch of discussion about this on the ColorSync Users list and, basically, ColorThink is considered the gold standard for this. It's really important to only compare profiles made using the same procedure and profiling software though. I did that for the comparison John is illustrating.
I think it's important to look beyond the total gamut volume number. One inkset may have a larger total volume than another but is it larger in ways that are meaningful? The HP Z3100 had a large gamut for it's day but it was all in the highlights - areas that didn't matter to many people. I find the greatest value in having gamut in the darker colors and that's an area where Epson and Canon are focusing on.
Another thing that's super important is to make prints and let them be the final judge! The results of the Perceptual intent aren't shown in these gamut maps - only the Relative Colorimetric intent. Sometimes all the numbers and science of it all doesn't jive with the real world final results with human perception mixed in.
Canon's gamut is really good in the deep purples and yellows. Are those important colors for your work? I've printing some photos of flowers with deep purples and yellows and the 8300 printer were noticeablly better than the 9900. My own photos don't contain those colors so it's a moot point for me. The fact of the matter is that both of these printers rock and it's unlikely that 99% of images have enough saturated color to begin with to stretch the limits of their gamuts. I'm finding the subtle differences in gloss differential and scratch resistance to be actually more important. On a Baryta paper these differences really show up.
When I make reviews I try to be pretty balanced with these observations and not rely to heavily on the tech data alone - as it can actually be misleading and steer people towards the wrong decision at times.
Softproofing with the intent is a pretty good way of doing that. Even so, the perception of pigments and the light scattering qualities with different pigments aren't taken under consideration. Canon's new yellow inks don't contain more yellow pigment than the previous generation, but because the particles are smaller the light scatters differently it has a very real impact on the way we perceive saturation, but not on the way it's documented colorimetrically. The yellows and greens visually appear to have more saturation because of the finer particles, yet that may not be shown in the gamut rendering.
Bottom line - you gotta look at prints. They'll show you all kinds of things that the gamut plots don't - and sometimes the results and conclusions are counter to what you might have determined from the numbers. Sometimes the gamut plots show that one printer has better reds for example but when you make prints with perceptual the other printer might clearly and obviously have much better reds.