Printing Grey with HP Latex 360

[Christian @ 2CT Media]

The intents may also effect colors inside the gamut, especially in the case of perceptual rendering. Easily observed in photography of flowers. Because of high color gamut and shades of petals, etc., are gradients of color, using the perceptual intent will move both out-of-gamut and in-gamut color in order to retain the perception of the gradient(s). Using the option of relative rendering, gradients may be lost and rendered as more of a solid color.

So explain how I get different results on a fully profiled and linearized machine? I posted pics of our testing to prove color shifts when rendering intents are changed. If grey/gray is fully neutral, you say its impossible, but if that gray contains C,M,Y data it shifts when output. As proven by the 2 pics I posted. So please explain to me that my very repeatable test across multiple machines, that pass G7 calibration tests according to ONYX, show changes in colors?

I'm not just arguing, I want to know what we are doing wrong.

 

[Bobby H]

Vinyl material profiles make a big difference with the HP Latex printers. Whether it's a neutral gray, a Pantone spot color or an interpolation of an RGB color (possibly way the f$%# out of gamut range) the choice of material profile will make a giant difference in the print. I'd rather use the pair of HP Latex printers our shop has now versus the Roland thermal inkjet printer we used to have. Printing a neutral gray on that was almost impossible. The tone could shift from green to red from one end of a print to another. It was maddening. At least the output on the latex printers is more consistent from one end of the print to the other.

Repeating what others have said, I never use a straight black percentage for a gray tone. I always include some kind of balance of full CMYK or even assign a Pantone spot color warm/cool gray or one of the numbered grays. Black should never ever be just 100% K. That's just going to be a dingy dark gray that shifts green or brown depending on the profile used. For a proper rich black I'll use either C75, M68, Y65, K90 or C30, M30, Y30, K100 depending on total ink limits. The first has a value of 298 and the second 190.

 

[ColorCrest]

I'm not just arguing, I want to know what we are doing wrong.

Maybe re-read my post #26 taking notice of the first line and paragraph, especially.

Trouble yourself with performing the exercise from the same post #26 except use the attached image file just because it’s immediately at your finger tips.

Again, the exercise is to use Photoshop > Convert to Profile using a known color space such as Coated GRACoL (you’re aiming for G7, correct?) or U.S Web Coated (SWOP) v2, which we know are standard printing press conditions, to preview the fact that the neutral grays of the image remain true when toggling through the rendering intents. Again, disregard Absolute intent.

Then, do the same while choosing the ICC output profiles from your printers. I think you’ll notice neutrals are shifting and that fact reveals the machines are not as calibrated and / or profiled as they might be.

So, if a customer supplies files which have truly neutral colored elements, poorly calibrated / profiled printers will likely have negative affects, obviously.

 

[dypinc]

Vinyl material profiles make a big difference with the HP Latex printers. Whether it's a neutral gray, a Pantone spot color or an interpolation of an RGB color (possibly way the f$%# out of gamut range) the choice of material profile will make a giant difference in the print. I'd rather use the pair of HP Latex printers our shop has now versus the Roland thermal inkjet printer we used to have. Printing a neutral gray on that was almost impossible. The tone could shift from green to red from one end of a print to another. It was maddening. At least the output on the latex printers is more consistent from one end of the print to the other.

Repeating what others have said, I never use a straight black percentage for a gray tone. I always include some kind of balance of full CMYK or even assign a Pantone spot color warm/cool gray or one of the numbered grays. Black should never ever be just 100% K. That's just going to be a dingy dark gray that shifts green or brown depending on the profile used. For a proper rich black I'll use either C75, M68, Y65, K90 or C30, M30, Y30, K100 depending on total ink limits. The first has a value of 298 and the second 190.

On HP Latex printers 100% K works just fine if you set that as the output value and do not use CM for 100%K or a rich black input value. I am wondering why you are using an output profile to regenerate the 100%K or any K only grey with exception of light greys which can benefit from low GCR using more CMY for a less grainy look which will be the CM challenge. Surly your RIP at least has a setting to preserve pure primaries and hopefully with ability to set a percentage level.

And by the way can you really see a difference between 100%K output value and and adding some CMY output value to that? I have tested this and never really could see a difference. For HP Latex I have never found a a reason for monkeying around with rich black input values in graphics when one can choose the output values in the RIP. Many jobs come in from customers that they have set a rich black which I always change in the to RIP to 100%K output value because if I let that rich black value be color managed it will look muddy and not as rich as 100%K output.

Even our digital press allows you to print pure 100%K which most times is rich enough black where using a rich black input values when convert to an output value by CM gains you nothing. The exception it to use a spot color where one can set output values adding a percentage of CMY to the 100%K.

 

[ColorCrest]

On HP Latex printers 100% K works just fine if you set that as the output value and do not use CM for 100%K or a rich black input value.

The topic is grays, not blacks.

What do you tell customers when they call and ask about designs using neutral grays?

 

[Bobby H]

And by the way can you really see a difference between 100%K output value and and adding some CMY output value to that? I have tested this and never really could see a difference.

I see the difference on our HP printers using Onyx Thrive and our Mimaki flatbed using RasterLink Pro. I even saw the difference previously when we had a Roland VersaCAMM and printing via VersaWorks. A straight 100% black doesn't print as a truly deep dark black as is, without any extra help from the RIP. Certainly you can use the RIP's functions to pump up the strength of the black value (which the RIP will do by pumping up CMY mixtures in with the K). But I find it easier to just set the color values I want in the design itself. That won't involve any risk of colors going darker as an expense of pumping up a plain 100% black value.

There's nothing wrong with using rich black formulas in artwork as long as it doesn't blow past acceptable total ink numbers. The only time I'm going to alter customer provided artwork with rich black values is if the value is something insane, like all CMYK values set at 100%.

What do you tell customers when they call and ask about designs using neutral grays?

It's very rare any of our customers want such a thing, but when they do we'll have them pick a specific target, such as a gray Pantone spot color. We'll usually run at least one or more test prints of color chip variations to check what values or settings are going to hit the target most accurately and do so without a color cast. We have less headaches with it now using our Latex printers than we did with our previous thermal inkjet printer (that one could print a gray that looked green-ish at the start of the print and shifted red-ish at the end, it was maddening).

 

[Christian @ 2CT Media]

Maybe re-read my post #26 taking notice of the first line and paragraph, especially.

Trouble yourself with performing the exercise from the same post #26 except use the attached image file just because it’s immediately at your finger tips.

Again, the exercise is to use Photoshop > Convert to Profile using a known color space such as Coated GRACoL (you’re aiming for G7, correct?) or U.S Web Coated (SWOP) v2, which we know are standard printing press conditions, to preview the fact that the neutral grays of the image remain true when toggling through the rendering intents. Again, disregard Absolute intent.

Then, do the same while choosing the ICC output profiles from your printers. I think you’ll notice neutrals are shifting and that fact reveals the machines are not as calibrated and / or profiled as they might be.

So, if a customer supplies files which have truly neutral colored elements, poorly calibrated / profiled printers will likely have negative affects, obviously.

We use Gracol 2006 coated as our color space; typical intent is perceptual. Our calibration passes G7 with a delta e of .3 for the neutral tones. This is why I'm so critical of the rendering, when have seen that if we move away from perceptual it alters the colors including gray when it is a build of CMY plus K.

 

[rdelight]

Hey guys, I got totally confused with that threat.

I'm experiencing big problems with my grays printing pink as well and I need help if anyone figured out.

I'm running HP Latex 365 with Flexi 12 and everything is the default, no special setting on the rip or the printer and I'm designing in Photoshop in RGB color mode, which makes my proofing easier and I don't know if that's the problem and printing on 54" Avery 1105 EZRS.

6 months ago I replaced all the printheads because my gray was looking green and I had something greasy on the connectors of the printheads. After I replaced the printheads my grays got better, but a little more like a mixture between pink and gray. The pink is especially noticeable inside the shop (a mixture of LED tubes on the walls and regular 8' ceiling tube lighting) and when I take the print outside it's more like gray but still a little pinky.

Now I started to print using 90% ink instead of 100 and looks it was a little better for a while and now it's getting worse again and I have to fully re-wrap one vehicle because it had to be gray and turned out pink and the whole time I thought it's just the shop lighting that's creating that issue until I pulled it out.

Do you think that my lighting is tricking the optical sensor of the printer or I have bad printheads again? I'm not printing every day, usually, when I get on or more cars in for a color change my printer stays off for a week or two at a time, I'm not sure if that can cause the printheads clogging.

Do you suggest changing all my lighting or LED and maybe place one right above the printer, change the RGB mode in my photoshop to CMYK, change rip settings, change printheads or something else?

 

[dypinc]

Re- Calibrate and if that does not do it create a new profile. In rare instances a media preset with it calibration can become corrupted, in that case create a new media present (do not clone) then calibrate and create a new profile.

 

[ColorCrest]

Do you think that my lighting is tricking the optical sensor of the printer or I have bad printheads again?

No, first take the above advice from dypinc.

Do you suggest changing all my lighting or LED and maybe place one right above the printer, change the RGB mode in my photoshop to CMYK, change rip settings, change printheads or something else?

If you change your lighting, get GE Chroma 50 or equivalent tubes. Keep using RGB mode in Photoshop. Don't change RIP settings until you fully understand them. Probably unnecessary to change printheads just yet.

Again, try what dypinc suggests. Good luck.

 

[rdelight]

Ok, I'll delete my current ICC profiles and download new ones, I'll re-calibrate after that and I'll see if anything changes.

I'm really trying to save on electric bills and LED lighting seems to be the best option, but if you think that's interfering with the printer I should probably avoid them, but I believe the printer lights inside the printer are led anyways.

I'll keep you posted, thanks.

 

[dypinc]

There is your problem, DON'T DOWNLOAD NEW ONES.

You have a L365 so create a new media preset (do not clone or download) calibrate and then create a new profile.

 

[jprout]

So far I've tried the re-calibrate method, new profiles and still my L26500 latex printer will not properly do a halftone of black. Tried using just a 4% black, then a PMS427c with a 25% tint and have run small areas on Duratex matte banner material. Every other print comes out as an actual grey. The others are 'pinky'. I am at a loss trying to get these 10ft. banners completed.

HP DesignJet L26500
Onyx 10.2.5.45

 

[dypinc]

So far I've tried the re-calibrate method, new profiles and still my L26500 latex printer will not properly do a halftone of black. Tried using just a 4% black, then a PMS427c with a 25% tint and have run small areas on Duratex matte banner material. Every other print comes out as an actual grey. The others are 'pinky'. I am at a loss trying to get these 10ft. banners completed.

HP DesignJet L26500
Onyx 10.2.5.45

For a halftone of black, try using the Replace Color feature of Onyx and use percentage of K only unless it is too grainy.

 

[jprout]

For a halftone of black, try using the Replace Color feature of Onyx and use percentage of K only unless it is too grainy.

I ran another small test banner, this time utilizing the Color Replacement tool replacing the eyedropper color with just 10% Black and no other color. It printed grey just as you said but I am nervous that it was going to print grey anyways since it was the 'every other time it prints grey fine' print. Coincidentally, the road race event just got cancelled 1/2 hr. ago due to corona virus outbreak fears. I will test later when I have more time.

 

[ColoPrinthead]

All this talk of rendering intents etc is all good and well, but why not just change your color build to another one that matches the color without the grain?

 

[rdelight]

Re-calibrating and creating a new ICC profile worked for me. Just in case I also changed the printheads and I also spoke with HP tech, he told me to do color calibration every now and then like every two weeks or so. Also when the print heads are older than six months you should do color calibration even more often.

 

[karst41]

Holy Sheite Muslims Batman.

I am using a 560 Printer and ripping with Flexi.

If I want Black it is 0/0/0/100
If i want a Simple Grey like 0/0/0/40 it is no Problem.

Here is the drill.

Flexi allows and recommends to use color correction to hit the PMS colors
and it hits them nicely.

HOWEVER: Lets say that I want the 0/0/0/45 (Grey)
With Color correction, the printer is going to fire all colors and that nice simple Grey is going to look like heII.

Turn Off color corrections, and there is your simple Grey.

Keep in mind that most greys are anything but Black White
and you will need to run color correction to hit the PMS.

My procedure with files like these is to run a reduced scale small print like 6"H
with Color Correction ON and one with color correction OFF

Simple Pantones are best printed with Correction Off Like PMS 286
Look at the Pantone Book. (Color Bridge) The Formula swatch shows a fantastic color. Not Look at the CMYK,, and yeah another bowl of MUDD

Turn Off the Correction and enter 100/0/85/0 and there is a stellar Match.
You might need to tweak the Magenta based on your printer.

 

[michael short]

Holy Sheite Muslims Batman.

I am using a 560 Printer and ripping with Flexi.

If I want Black it is 0/0/0/100
If i want a Simple Grey like 0/0/0/40 it is no Problem.

Here is the drill.

Flexi allows and recommends to use color correction to hit the PMS colors
and it hits them nicely.

HOWEVER: Lets say that I want the 0/0/0/45 (Grey)
With Color correction, the printer is going to fire all colors and that nice simple Grey is going to look like heII.

Turn Off color corrections, and there is your simple Grey.

Keep in mind that most greys are anything but Black White
and you will need to run color correction to hit the PMS.

My procedure with files like these is to run a reduced scale small print like 6"H
with Color Correction ON and one with color correction OFF

Simple Pantones are best printed with Correction Off Like PMS 286
Look at the Pantone Book. (Color Bridge) The Formula swatch shows a fantastic color. Not Look at the CMYK,, and yeah another bowl of MUDD

Turn Off the Correction and enter 100/0/85/0 and there is a stellar Match.
You might need to tweak the Magenta based on your printer.

My problem is when I bring a corel draw file into flexi, I open the last icon which shows the colours and the CMYK dosent match the output so it prints a different colour. Yes I have turned colour correction off and the Gray problem is fixed however if the file contains other colours they are effected with it turned off.