Latex 360 color consistency is not there

[Morkel]

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.

Really appreciate your insight here. Thanks heaps, gives me something to go back to HP with. Not the Onyx vs Caldera stuff, but the fact that they aren't as consistent as we've all been led to believe.

 

[Correct Color]

I don't see why they can't. For example in the Fiery XF RIP both options are available in HP's aqueous printers.

In every other RIP I've seen as well. I've pounded on that any number of times. "If it can be done with the Z6200, why not this thing?"

I've been told that it isn't possible.

Of course, I've also been told this machine RIP's in the printer.

We'll see.



Mike

 

[dypinc]

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.

I don't think it is advantage to do ink limiting/linearization with the RIP on the L3xx series, in fact in my testing it limited your gamut. What I suspect is going on is that with my RIP anyway the inks are printing pure as they are supposed to be when printing ink limiting/linearization targets. The same as when you tell the RIP to print pure color like 100% of a color prints that color with no CM the way we get the really nice rich blacks with these latex printers. And, I can get Yellow and Black to print pure from 0% to 100%. I can do the same thing with Magenta and Cyan but based on HP light ink curves the light inks will start to be used. Or you could set the media setting to CMYK only.

Since a regular color managed job can not be printed without the printer processing it without some sort of internal calibration/ink limiting going on you are essentially double ink limiting/linearization the printer if you also have your RIP doing that. In other words a regular color managed job going through the printer, the printer has a different characteristic then when you did the ink limiting/linearization. That was not true with the L2 series and another HP screwup with the L3s. If they wanted to make the L3s a contone printer why not just address like any other aqueous printer and just make printer driver for the different OSs. Why this half-way screw around. I guess it is one good thing that you can at least print each color as pure, but then the joke is that when sending a regular color managed job the printer adds ink limiting and calibration on top what it gets from the RIP.

I needed to make some fabric profiles over the weekend and because you can not calibrate in the printer with this media setting, in the past I did the ink limiting/linearization on the RIP. So this time I did some testing on the theory that there was still a calibration going on on the printer. It pretty much confirmed what I am starting to believe about double calibration if ink limiting/linearization is used on the RIP. I got much better gamut/ink lay down then what I got in the past when doing ink limiting/linearization on the RIP. While profiling would possibility compensate for the double calibration going on when using ink limiting/linearization on the RIP I don't think it can correct when too much ink limiting is going on. I suppose different RIPs might handle this differently or maybe I should say that the printer might handle this different from different RIPs. I can print 100% (with proper CM and a setting of Pure Color) of C, M, Y, or K from the RIP and it matches the first row in the internal printer calibration target which leads me to believe there is no addition calibration going on at at least 100%. But where does the printer calibration kick in is the big question, at anything less than 100% of the pure colors or if there is more than one color involved. Obviously ink limiting starts at some point.

My experience is with RIPs if you address it as a CMYK device then you must do ink limiting/linearization on the RIP. If you address it as and RGB then you don't because they have they own internal characterization. Now with the L3s we have a CMYK addressed device with it's own internal characterization.

 

[Correct Color]

dypinc

The reason I do in-RIP linearizations on the 300 series is that I want a more robust linearization that can be had by an on-board spectro reading a seven patch per color target set. Again, from my own personal observations, what I have seen is that the onboard spectro-created "calibrations" are just not robust enough to be used for anyone serious about hitting consistent neutrals.

However, theres seems to be some confusion in the industry that I've seen on other forums that linearization in and of itself has some effect on gamut. And the fact is it does not. Linearization merely defines tone curves for each ink within an existing gamut boundary.

If I was to change any inking characteristics -- single channel or multi-channel ink limits -- then I would be altering the gamut, and if the contone settings allowed laying down enough ink to 'overdrive' the thing and then cut it back in the RIP that might even be a backdoor way to get some control over it, but in the case of most media, I haven't seen that to be the case.

As far as the machine always using a calibration, yes, maybe I wasn't clear, but that was a good deal of my point. I'm convinced it has a default "calibration" that it returns to if it does not a a custom one in place, or if anything triggers the custom one to be determined "obsolete."

And note that while I wish the machine would be just a dumb printer and let the RIP make all dot-generating decisions, it's certainly possible to make one linearization on top of another with no ill effects.

What is required -- regardless -- is that the machine print consistently.

 

[dypinc]

dypinc

The reason I do in-RIP linearizations on the 300 series is that I want a more robust linearization that can be had by an on-board spectro reading a seven patch per color target set. Again, from my own personal observations, what I have seen is that the onboard spectro-created "calibrations" are just not robust enough to be used for anyone serious about hitting consistent neutrals.

I am going to test this again. Since I have only recalibrated and created a new profile for a few medias since the last firmware update I might as well go back and revisit this.

dypinc

If I was to change any inking characteristics -- single channel or multi-channel ink limits -- then I would be altering the gamut, and if the contone settings allowed laying down enough ink to 'overdrive' the thing and then cut it back in the RIP that might even be a backdoor way to get some control over it, but in the case of most media, I haven't seen that to be the case.

I tried that at one point and can't say it was of much value if any at all. Anyway the real problem with the ink limiting is in the 8 pass and under range.

 

[dypinc]

I was forced to do a new color profile today so I thought I might as well test this.


First off I re-calibrated and did a new profile (RIP based) on 12-2-15. I loaded the latest firmware .12 on 12-9-15. Today I loaded the media in question and it said obsolete, so I did a calibration. OMG was it off, gray were really blue. Pretty much show that something is not right with calibration. Can’t imagine the firmware screwed it up that much but something happened.


So first since I needed to get the print job done and wanting to test this not using the printer for any CM, I created a new media only linearizing on the RIP.


This brings the question. Fiery XF RIP. When I read the ink limits per channel I get Cyan 99% Magenta 99% Yellow 100% Black 99%. Should I leave them at that lever or thinking this is a contone ink limiting device just set them to 100%? Now I went to linearization target and read that. Moved on to total ink limit and again set that to 400%. Now printed and read the Quality Control target and went on and created the profile. Printed good neutral grays and sample test print looked correct.


After the print job I ran re-linearization. It recommended re-linearizing. Off 3.95de After printing and comparing the target you could visually tell there was less light cyan being put down, and the measurements confirmed that. Then I took a close look at the test prints with a gray border and could see that the gray was not consistent from the start of the print to the end of the test print. Maybe best to replace the lc/ mc head, and I am thinking that I should replace the other heads as well before doing a round of profiling even though the nozzle checks look good. C/B heads have over 5000ml through them and one Y/M and the lc/lm head has over 4000ml. Seams the L25500 was much quickier to tell me heads needed replaced. What kind of head life are others seeing on these machines?


When it comes to hitting grays I wonder is using just one lc/lm head another mistake with this machine. Not real redundancy when nozzles drop out like the L2 series.

To be continued…

 

[Morkel]

I'm still waiting for the HP tech to contact me. If I get any answers from him I'll be posting them here immediately. I kind of trust this guy, more than any previous HP techs, because he's the only one who ever admitted that horizontal banding is an issue on the L28500s & L260s. Every other tech said that it just never happens... even though we sent them samples. Lots of samples.

 

[dypinc]

My tests are confirming the same thing as yours. All existing media calibrations and profiles before the last firmware are junk and there is no way to get them back. Like you I tried the reset calibration and then do a calibration which made really no difference. It was still way off. The linearization and profile I made a few days ago with RIP is still on.

It does appear the only real way to get back correct color is to create a new media and go from there. At this point I think I am going to do the linearization and profile with the RIP, as I have lost all trust of the onboard CM.

 

[scott pagan]

... because he's the only one who ever admitted that horizontal banding is an issue on the L28500s & L260s. Every other tech said that it just never happens... even though we sent them samples. Lots of samples.

yep. we have seen it on our HP LX850s and LX3000s too.

 

[dypinc]

Interesting.

I just talked to a HP tech and when I mentioned the invalidating all previous calibrations and profiles with the last firmware his response was, Oh yeah.

 

[derekw13029]

I know this sucks, but this is one area where not really using custom profiles comes in handy!

If the firmware changes the color output, sometimes it's easier for me to just slightly adjust the image in photoshop to make it print the way I want.... :/

The drawback to this is: if profiles change over the course of updating firmware, I can't rely on a saved old file to match previous versions of art reproductions....

Pretty sure I'm running the latest firmware on my HP L330, haven't *noticed* any differences in output on my custom profiles, but to be honest I'm not sure if I have ran an old file that I would notice.....

My workflow is conducive to every new file being a new job. I prefer to edit images rather than keep editing profiles and playing with my RIP. Not sure if that's any better, but it works for me so far..... :/

 

[Vinyldog]

I'm with you guys

I find the on / off switch to be in an inconvenient place

 

[dypinc]

I know this sucks, but this is one area where not really using custom profiles comes in handy!

If the firmware changes the color output, sometimes it's easier for me to just slightly adjust the image in photoshop to make it print the way I want.... :/

The drawback to this is: if profiles change over the course of updating firmware, I can't rely on a saved old file to match previous versions of art reproductions....

Pretty sure I'm running the latest firmware on my HP L330, haven't *noticed* any differences in output on my custom profiles, but to be honest I'm not sure if I have ran an old file that I would notice.....

My workflow is conducive to every new file being a new job. I prefer to edit images rather than keep editing profiles and playing with my RIP. Not sure if that's any better, but it works for me so far..... :/

I understand what your saying, but my point is, that it is now quite obvious that the CM on these printers can not be trusted. That is why I am moving everything to the RIP. Whatever they want to do with their firmware or just the changes as the printheads wear from usage or need replaced, reading a linearization target from the RIP returns the color to a correct state, no other monkeying around needed.

 

[Morkel]

My tests are confirming the same thing as yours. All existing media calibrations and profiles before the last firmware are junk and there is no way to get them back. Like you I tried the reset calibration and then do a calibration which made really no difference. It was still way off. The linearization and profile I made a few days ago with RIP is still on.

It does appear the only real way to get back correct color is to create a new media and go from there. At this point I think I am going to do the linearization and profile with the RIP, as I have lost all trust of the onboard CM.

I guess this means that I'll be writing down all of the settings for every media, and then making them again from scratch. The question is, how long until someone else at HP puts something in the next firmware that'll invalidate these new ones???

 

[dypinc]

I guess this means that I'll be writing down all of the settings for every media, and then making them again from scratch. The question is, how long until someone else at HP puts something in the next firmware that'll invalidate these new ones???

Well they can do what ever they (HP) wants but I am not touching any CM on the printer again. I am a going to be doing all CM on the RIP from now. Every media calibration can say Recommended and it's going to stay that way.

Now I will say that I am pretty sure that my lc/lm printhead was malfunctioning and printing inconsistent, but still it is no reason for calibration not working correctly for existing media.

And we thought CM on the printer might save us some time. Wonder has HP pulled all media profiles from there web site for the L3 series. I guess you can test deleting a media and downloading it again and see how it prints.

 

[dypinc]

I guess this means that I'll be writing down all of the settings for every media, and then making them again from scratch. The question is, how long until someone else at HP puts something in the next firmware that'll invalidate these new ones???

Hows it going on your end?

I have been Linearizing and Profiling my most used media the last couple of days. I changed printheads after profiling the first media, just to then test re-linearization on the RIP and was able to bring it right back in line with where it was before the print head change.

I don't remember are you doing your color management on the printer or the RIP or some combination there of?

Doyle

 

[Morkel]

Hows it going on your end?

I have been Linearizing and Profiling my most used media the last couple of days. I changed printheads after profiling the first media, just to then test re-linearization on the RIP and was able to bring it right back in line with where it was before the print head change.

I don't remember are you doing your color management on the printer or the RIP or some combination there of?

Doyle

I'm of in a holding pattern, waiting for the HP tech to visit. At the moment I'm running all of my SAV (literally all of it, mono, poly, cast, wall, etc) off the one media preset, the new one I made as a test that seemed okay. I know the white points will be different but it's better than having 15 different SAV variants that will branch off in to different and random colour shifts.

I don't have any profiling equipment so everything is through the printer. I'd be hesitant to go down that path at this moment anyway, with the way it's been I'd be manually re-profiling every one of the 30-40 medias weekly.

While it's under warranty I'll wait until HP give me some answers.

 

[dypinc]

I'm of in a holding pattern, waiting for the HP tech to visit. At the moment I'm running all of my SAV (literally all of it, mono, poly, cast, wall, etc) off the one media preset, the new one I made as a test that seemed okay. I know the white points will be different but it's better than having 15 different SAV variants that will branch off in to different and random colour shifts.

I don't have any profiling equipment so everything is through the printer. I'd be hesitant to go down that path at this moment anyway, with the way it's been I'd be manually re-profiling every one of the 30-40 medias weekly.

While it's under warranty I'll wait until HP give me some answers.

Biggest issue I had besides the calibration not working was the lc/lm head was malfunction and seemed to me to be throwing way more lc ink down then it should have been. I supposed if pink is the issue it would be the lm ink.

Once that was changed color has been very stable. Don't know if that head malfunctioning contributed to the onboard calibration problems or not. Since I have the tools I just decided it would be better to use them for CM then the onboard printer ones. For example I can measure and see what inks are not normal by how much deviation they have.

 

[Morkel]

Biggest issue I had besides the calibration not working was the lc/lm head was malfunction and seemed to me to be throwing way more lc ink down then it should have been. I supposed if pink is the issue it would be the lm ink.

Once that was changed color has been very stable. Don't know if that head malfunctioning contributed to the onboard calibration problems or not. Since I have the tools I just decided it would be better to use them for CM then the onboard printer ones. For example I can measure and see what inks are not normal by how much deviation they have.

The problem with mine is that on, say, my Mono preset, the colours are very green. On my Poly preset, they're now a purple colour. Others have gone in different directions, and these medias were all offshoots of the Poly preset (ie, I made the poly one first, then I duplicated this one to make mono, wall graphic, etc). Just with slightly different temperature & vacuum settings etc.

 

[dypinc]

Caught my L360s color being off this morning. This is about 3 weeks after changing heads and doing new linearizations and profiles. Printing pinkish warm this time.

Difference now is since since I no longer use the printer to calibrate I did I re-linearized with the RIP which tells me what is off. Shows peek shows 7.7de Cyan shows as off about 2.5de. In looking at the linearization targets it was pretty obvious that it was the light cyan causing the problem. Printer information only shows four bad nozzles for lc. Did not do a nozzle check print though.

The great thing about using the RIP to do the Linearization, re-lineraization brought the color back.

I am going to keep a close eye on this and if this fluctuation continues I am going to get on HPs case.