For what it's worth, I'll share some of my experiences with these machines, and a few tentative conclusions I've reached along the way.
My first experience and the first overall impression I had of these machines is that I hate the entire idea of them taking all inking control away from the RIP and contoning them in the machine. The built in ink splits are terrible, and guarantee a grainier print than can be obtained by a properly profiled 25500/26500/260.
My second observation is that the onboard-made ICC profiles are, at best, adequate but uninspiring. They'll work for a lot of midrange work, but for anyone serious about color, they have serious black generation issues, and their perceptual rendering intent has some serious clipping issues.
And of course that's all before any color inconsistency issues.
As far as the color inconsistency goes, here's the path I've been down:
When I first saw these machines and profiled them, it was at a shop that had several, and was running Flexi-Signs.
Pretty well-known place, and they had had 26500's for years, and ran them with no issues.
First time I profiled the 360's, I did the onboard calibration, then I ran a linearization in the RIP as well, then I made the ICC profiles with a 3rd party engine and imported them in.
There were initially three machines, and because each one was a tiny bit different, and because these guys want to print across all three machines for individual projects, I profiled each one individually.
And it worked. All printed correctly, and all matched exactly. Visual test, by the way; I have a test image that has several neutral and near neutral images on it. My test is always to print it on two machines, then cut across one and overlay it on another. If there are any inconsistencies, you'll see them. Over the years I've found this to honestly be a much better indicator then measuring Delta E.
However, as soon as they did any maintenance, the machines no longer matched.
I re-profiled them, and didn't hear anymore from this particular client for awhile.
However, I have other clients with the machines, running them with other RIPs, and over time, what I came to conclude was that these machines are always applying a canned linearization, whether you ask them to or not.
And what I concluded happens is that when you do the "calibration" routine as part of media creation, the machine makes a "calibration/linearization" file that it uses until any situation happens that causes it to dump it. When it does, the front panel message changes to "obsolete", the machine reverts to its default "calibration" and of course neutrals in particular go right out the window.
Then of course you can do a "recalibration", however what you're using is a seven patch-per-color target, and an on-board spectro. Not a really robust way to do a linearization, and my experience has been that every time I do that, I'll get a different result. Probably acceptable if you aren't completely color critical; most definitely not acceptable if you are.
However in fairness I will point out that I've heard and seen that other people have gotten better results.
I have another client in Minnesota with one of these things and I was actually boarding a plane to go see him when I got a call from a guy at HP who told me that the reason for the issues my other client was having had to do with the RIP they were using. And the issue is that the 360 does not RIP in the RIP, it RIPs in the printer.
I told him I thought that was absurd, but he insisted. He also told me that the only RIP manufacturer who had figured this out and was capable of dealing with it was Caldera, and HP had a team going out to my first client's to install Caldera and resolve the issue.
That was just before the holidays, and as of yet, I don't know the resolution there.
However, I spent two days in Minnesota working with a 360, in this case driven by Onyx, and what I can say is that we did a series of tests, and they all corroborated my theory. We made profiles using the onboard linearization, then an Onyx linearization and then a 3rd party profile, and they printed perfectly.
We pulled and re-installed a printhead, the display went to "obsolete", then we reprinted the same image, and the color had changed.
We "re-calibrated" and they changed again, but not to where they had been before.
Then we made a media with no internal calibration, did an Onyx linearization and a 3rd part profile. Print was accurate and exactly the same as our first print. Then we again pulled and re-installed a printhead, again reran the image, and it did not change at all.
Both myself and the client were sure we had it. Unfortunately, this machine is still not stable. It has continued to wander around.
I'm working with the client remotely on a series of tests, but as of yet, I don't have anything entirely conclusive.
Also of note here and kind of "off the record" but I talked afterwards to a friend at Onyx, who told me that at HP, there are something akin to two armed camps: The Onyx Camp, and the Caldera Camp. And the Onyx camp is convinced Caldera is the Devil, and vice versa.
Which is kind of funny... unless you have one of these machines and you'd like to get this issue resolved.
