As far as gloss differential, it can be there depending on the paper. To me, it's not a thing I worry about. Matted and framed, I would challenge anybody to consider it a "big deal".
HP on the other hand with their pigment inks was FORCED to deploy a gloss enhancer because their inks resembled the original Epson pigment inks with really bad GD. Epson had played with a GE in their R890 & 1800 printers designed to print on really glossy paper. So, rather than have to devote an entire channel for a clear glop, they redesigned the resins in the inks to minimize it, which they have done. Can you see it if you look hard enough? I suppose...is it objectionable? Not to me and it's invisible once matted, framed and hanging on a wall. YMMV
I hadn't been able to print my images on the same or similar paper at Photokina but can say that what I saw confirms gloss differential is controlled by HP to the point of a non issue for GD, but don't forget the increase in cost and printing time, and fragility of the surface. Epson has very GD by nature, but is not completely eliminated, nor is it for any pigment printer I have seen to date.
It is extremely variable though on different surfaces. For example, at the Innova stand they had all three brands of printers. Kind of surprising to see , they had many great images printed on bad combinations of media and image style. On certain media the Epson VM inkset and the 7900 had substantial GD on glossy Innova (can't remember the name), as did the Canon too. HP with GE there was little or rather none in the highlights.
So say what you will, but remember the media is just as important as the inkset. The same is true on HP, as without GE it can sometimes be quite poor, whereas both Epson and Canon get the job done well. One of the reasons I felt when the Z 3100 was released the GE was not marketed as an important element as it should have been. It is a good solution, one that works. IF not for GE, the inkset they have is not up to par with the others as far as gloss diff goes.
I'm not a big fan of HP. I own a Z3100 and have noted in this thread and other threads that I have seriously considered selling it and switching to Epson. I think HP customer service, tech support, software and drivers are clearly inferior to Epson. And the new 7900 is probably superior to the Z3200 in yet other areas. So I am not a partisan defender of HP, and in fact have been very critical of HP.
Having said that, the above criticism of HP, and implied defense of Epson by Schewe, is simply not balanced. Or accurate.
The readers of the forum only have to run their own test. Take a print on photo paper that has clear evidence of gloss differential** (GD). Put a piece of glass over it. I did that in response to the above posting by Schewe and his flat assertion that GD is "invisible once matted, framed and hanging on a wall." I used examples of GD printed on Epson Luster from both the Epson 4000 and the HP Z3100 when printed without gloss enhancer.
Can you see the GD? Yes. You can see GD just as clearly through glass as without a mat and glass. That is not an opinion, that is a fact. Test it yourself.
Partisan attacks on HP don't change that. Schewe's reference to GE as "clear glop" is simply a cheap shot, and a debating ploy to change the subject, that doesn't address the issue. The plain fact of the matter is that HP solved GD with the Gloss Enhancer (GE). Did they have to do it because their inks fail some other standard as asserted above? I don't know. What I do know is that combination of HP inks with GE has come very close to entirely eliminating GD. On top of it, I understand that the Z3200 works even better in that regard with control over the application of GD, although I can't personally attest to that.
See the above quote from Neil Snape, who has used both printers, and his assessment of GD and GE on the HP Z series. Neil states that "what I saw confirms gloss differential is controlled by HP to the point of a non issue for GD," and that "I felt when the Z 3100 was released the GE was not marketed as an important element as it should have been. It is a good solution, one that works." With regards to Epson, Neil reports that "On certain media the Epson VM inkset and the 7900 had substantial GD."
Here is my interpretation of the above assertions on behalf of Epson. Epson has not solved GD, based on statements from those who have used both the Z3100/3200 and the 7900. So that assertion that GD doesn't matter when framed is a weak defense of a problem that still exists with the 7900.
The degree to which GD still exists is something that we each must individually evaluate -- assuming that you live near one of the largest metro areas in the US and can see both printers in operation. If you don't live in such an urbran area, you must depend upon the reports from those who have used both printers.
Finally, there is a real pattern here in the approach used to defend Epson. Epson has, thus far, failed to address two of the strengths of the HP Z3100, even though it appeared on the market two or three years ago. HP revolutionized the market with their on-board spectro for PROFILING PAPERS and GE.
So the current defense of Epson is to assert that these features are not important, and therefore it is not an issue that Epson has still not included these features in their new printers. That is about all that Epson can say, when HP has the features, and Epson does not.
The fact of the matter is that HP is marketing a printer for about the same price that still includes two very nice features that Epson lacks. The Epson marketing guys blew it, especially on the spectro, when they didn't include utilities to make profiles (based on reports in in this thread). Epson has had close to three years to address these advantages in the HP printers as compared with Epson printers that lack those features.
Epson just plain dropped the ball, and arguing that these features aren't important doesn't change that.
The degree to which these HP features matter to a consumer is a decision to be made by each consumer who is looking at both printers in the same price range. But calling GE "clear glop" does not change the fact that it works, and works well. And then there are those who argue that an on-board spectro is not important, and the profiling of papers can be handled through other options -- even though it is available on a very good printer for about the same price as the Epson so why not buy a printer with that option instead of one without the option? Others argue that a spectro is not critical to the actual performance of a printer. But the same can't be said for GD and GE, can it? GD has everything to do with the actual performance of the printer. In the case of the spectro, the argument is also made that a manual package can be used so there is another alternative. But that is not the case with GD, unless some spray in a can that can be applied outside in an open area. Frankly, I'll take the HP solution, that is applied indoors, and as part of the printing process, rather than spray in a can.
Individual consumers can judge GD for themselves, if they can find a dealer with both printers who can run the tests, assuming that you live in one of the largest urban areas of the country. I will see if Epson will print a test image from a DVD at one of the Print Academies demos for that purpose, since a 7900 will not be available in my area. If Epson declines to do such a comparison, I will report that, and I suspect that they will use any of a number of excuses to refuse to spend three minutes to print an 11x14. If so, I'll report that as well. If Epson has come very close to eliminating GD with its new inks, I will be the first to eat crow, report that fact, and applaud the Epson solution.
** (I am using the term GD to refer to a clear difference between areas with ink versus plain white paper for complete white, and also when that appears in areas of gray or black. If this bronzing, rather than GD, then use that term.)
