L25500 prints too dark - any ideas,please?

[Ian Stewart-Koster]

Despite a head cleaning, and head realignment, if I create a box of CMYK 0,0,100,0 (ie 100% yellow)
and save it as a PDF from Corel Draw, then open it into Onyx Production House RIP, the yellow box prints with a dirty darker hue - not 100% yellow alone, but it seems to have murky black spots through it.

Most colours print a quite fair few degrees darker than their PMS equivalents should be.
Using the 'print lighter' option in the job editor, makes no difference - it's still generally toodark, and the yellows are not pure yellow.

I'd appreciate hints to try to get colours to print a bit more accurately, thanks!
On most things, variations are OK, but when I need a good yellow, or a PMS green to match, I need that colour, not a variation of khaki!

PS the heads don't need replacing, according to the printer itself. The auto test print comes out looking good. Genuine HP [HASHTAG]#789[/HASHTAG] inks. I've changed media, and I've used the same media, but told it it was something with a different profile- no difference in murly colours. Pure orange looks more like caramel!

 

[dypinc]

Give us some more information about your Linearization and Profile making process. Possibly an error there or bad spectro. Also there is a setting for pure primaries and I believe Onyx has an option to set the output colors independent of Color Management.

 

[Ian Stewart-Koster]

Give us some more information about your Linearization and Profile making process. Possibly an error there or bad spectro. Also there is a setting for pure primaries and I believe Onyx has an option to set the output colors independent of Color Management.

Thanks - I simply downloaded a bunch of Onyx profiles for assorted media I had - or the next closest I could find.
Eg Avery matt sav MPI 3021 or whatever it was, and others for banner material - Oracal permanent gloss polymeric.
All print too dark for my liking and won't print a pure clean yellow or red.
I've not made new profiles myself - just left the curves as they were in the downloaded files.

I've also tried thre wrong profiles, eg telling it that matt vinyl is installed, or aqueous paper, when glossy vinyl is there -to make no visual difference either, when I send the square or swatch of Y=100, or a swatch of PMS 289 that I'm trying to match - but it gives me something resembling a perfect PMS 297 or 298 instead of 289.

I appreciate the help.

 

[dypinc]

There is your problem. Canned profile not made for your specific printer or environment. What a waste of time and materials.

Make your own profiles. There is no substitute for proper color management.

 

[dale911]

I know the l25500 can do perfect yellows as I still use that printer daily. It has to be in your profile. Are you running Onyx with "all color profiles on" or a different setting?


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[chafro]

Try different profiles,, if the problem is still there it's a bad print head.

Heads can be bad in some cases even when the tests look good.

Latex can go great yellows.


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[ddarlak]

post a pic of your head print out. I have a 25500 now that is leaking black into the yellow and i get the same results your talking about.

 

[jayhawksigns]

post a pic of your head print out. I have a 25500 now that is leaking black into the yellow and i get the same results your talking about.

We had that issue as well too. Out of curiosity, what are your ink levels and how much ink has the heads fired?

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[MikePro]

if you want to run a print from a file of 100Yellow, turn ICC Profiles Off. Same goes for any CMYK value you will to retain on the fly, or simply create spot colors that your profiles won't adjust in the RIP.

 

[Suz]

deleted

 

[eahicks]

Thanks - I simply downloaded a bunch of Onyx profiles for assorted media I had - or the next closest I could find./QUOTE]
.

While this practice is good in a pinch with a material you use very seldom, it is never a good idea for your everyday work where color matters. That profile you downloaded for XX Brand adhesive vinyl was created by another person, with a different printer, an older ink set, in a different temperature room, and perhaps completely different climate, on an older run of vinyl. So what you run with that profile WILL inevitably look wrong. You have to create new profiles, or with the newer printers, re calibrate every new batch of inks or vinyls

 

[Hotspur]

OK so there's an easy solution to this (although the best solution is to build your own profiles as everyone says)
Even if you made a custom profile you will still see this happen to some extent.
What Onyx is doing is correct - the profile is altering the pure yellow you are sending into a yellow that the colour management says is correct (although most don't like the look of a "dirty" yellow even if it is correct theoretically.
Dypinc has made the right call - I'll flesh it out. In the input color management section of the quickset you can dive in and select your own profiles for RGB & CMYK Vectors and bitmaps etc - to the right of these selections is a small icon that looks like a square colour swatch. Hit this and you will be able to select a colour that will be preserved as a "pure hue" - in your case select the yellow.
Then whenever you select a pure yellow in the application, Onyx will keep that pure yellow in the rip whilst still changing all the other colours according to the correct colour management policy so everything else will be unaffected.
This dialogue is often also used by people who want the pure black in the original to only use the black / grey printhead in the rip so other colours are not thrown into the mix causing registration issues etc.on text.
Good luck!

 

[Bly]

The printheads are designed to have a limited life so if you want reliable repeatable colour you need a spectro to linearise output regularly.

 

[dypinc]

Prue hue, Pure Primary, etc. different RIPs call it by different names. And the really cool RIPs allow you to pick a color with a eyedropper and give it a different output color. Pretty sure Onyx can do that. I know Colorgate can. I loaded a Linux/Caldera demo on a drive on an unused PC box the other day just to see if it had that feature but I could not find it. Any Caldera user know if that can be done?

One thing that is really cool about the eyedropper is when jobs come in that are created with rich blacks (we all know what happen with Latex ink in that situation) that I can just pick that rich black out and assign it 100K output only when printing with the Latex inks.

 

[tollerdad]

When you print all plots are your yellow patches the same yellow? One darker than the other?

 

[Ian Stewart-Koster]

When you print all plots are your yellow patches the same yellow? One darker than the other?

I'll upload some print photos soon.
No - in the print head cleaning, & test, the upper block is murky, and the lower one is clean.
Thanks for the helpful replies, guys!

 

[Ian Stewart-Koster]

Looking at that, There's a pink block to the right of the 123456 numbered test tube shapes, and I thought that pink block should be yellow. (1st & 2nd pictures)
(or is it meant to be pink/magenta with an orange left edge ?)

Looking at the Nozzle Check blocks,(3rd & 4th pictures) the upper yellow square is murky with black in it, but the lower yellow square is clean, yet the lower black one is streaky with clogged nozzles or missing lines.

Thanks for any advice. Does this mean both black/yellow print heads may be crook?
IN the meantime, I'll go and run another head cleaning cycle...

 

[Ian Stewart-Koster]

Update:
after 10 head cleanings of the k-Y heads, it's printing an 80% cleaner yellow in the top line, and reds, oranges, yellows & greens are much closer to PMS expectations than the muddy misses they'd been looking like before.
Turning All ICC profiles on, was better than all profiles off, which gave a washed-out look..

New query: when I was sending test squares to be printed, I made them in Corel Draw, and filled them with the colours I wanted... then I esported that as a JPG, then reimported it and put it under the original squares in Corel, then I esported THAT as a PDF.

I used that as my test file.
Oddly the jpg part was truer in the blues, and cleaner in the yellows & oranges, than the direct vector-to-pdf line of boxes.
A box made up of 100% cyan in corel, printed like an insipid aqua from the vector box, but its corresponding mate exported as a jpg and brought back in, which looked the same on the monitor, printed just the right colour as per my PMS swatch book.