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Onyx ICC engine...

Offline Pauly Posted 05-24-2016 - 06:26 PM
Post: #1
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Onyx Version:
12.0
Printer(s):
Oce Arizona 480XT

I believe i have found the issue with the onyx ICC engine,

I was looking around the onyx folder to see what i could find. In the profiles folder, I find the defaultCMYK, DefaultCMYKO ect ect files. Looks like the ones you choose to specify what ink configuration your printer has. So i decided to pull the cmyk file and put it into photoshop for a soft proof. What do you know, it looks like the rest of my onyx made profiles.

I then put it into Colour think pro to have a look at it. Gamut range is small, not good. It's smaller than what my printer gamut range is.
All of my profiles made on the printer have a very similar shape, no matter what program it's made in, (onyx, i1p, basiccolor)

What stood out is that the CMYK profile onyx is using is 3M Match Print.

I kept looking around, Found the CMYK output profile, again, it's 3M Match Print.

I found the default onyx profiles (onyxCMYK), and a few others, all the onyx ones have terrible colour, All similar to 3m Match print.

So to me, It looks like what ever onyx is doing when creating a profile, It's creating it to a 3M Match Print specification.

I tried to change the output files and the cmyk ones to a CGATS CRPC7 but that didn't work.

There has to be a way to change this.
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Offline janA Posted 05-25-2016 - 07:37 AM
Post: #2
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25 Posts
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Onyx Version:
7.3.2
Printer(s):
Oce Arizona

It looks like you are looking at the input profiles, not output profiles.
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Offline Pauly Posted 05-25-2016 - 07:57 AM
Post: #3
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Onyx Version:
12.0
Printer(s):
Oce Arizona 480XT

These are output profiles. They're labeled CMYK, CMYKO ect.

The only time i've seen the same list is in the printer configuration settings in media manager choosing what ink the printer uses.

I've opened all of them in Color Think Pro and they're definitely output profiles as they're listed as CMYK.
I've used them for soft proof for testing colour output in Photoshop cs6 and it's under the CMYK list.

My onyx made profiles made with the onyx engine and these "default" profiles look nearly identical. Except the gamut range is much larger from the printer profile vs the default. But seems as though the colour has been compressed to match the default profile.

I want to change this default profile, but i have no idea how.
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Offline Correct Color Posted 05-25-2016 - 10:02 AM
Post: #4
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128 Posts
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Onyx Version:
10
Printer(s):
Epson

Pauly,

Interesting stuff...

But it doesn't work that way.

Of course one of the problems in situations like this is that if I don't see something myself I don't know just exactly what happened...

But I can tell you that while I have some pretty well-documented issues with the Onyx ICC profile-making engine, what you're describing here isn't one of them.

It does not limit gamut to any pre-defined default. It makes a profile based on whatever measurements you feed into it. I've used it enough to be confident saying that. But you can certainly see for yourself just by pulling the ICC profiles out of any Onyx stock media for any printer and taking a look at them. If they're named "ICC Profile Table", you can be assured they were made by the Onyx engine. Also in either Colorsync or a Mac or in Color Think Pro you can look up the creator signature, which for the Onyx engine is "ONYX."

Just any small handful will show you they're not limited to or in any way defined by that profile.

I do know that if you create a media profile in Onyx and do not generate or import an ICC, that profile will be used as the default ICC in that media. I recognize its soft-proof from the times I've forgotten to import profiles -- or set them as the default -- myself.

But again, the issues I have with the Onyx engine mainly have to do with rendering intents. It does not do what you're suggesting here. How you got that result... I don't know, I wasn't there.

Also kind of interestingly, the lowercase defaultcmyk file is an ancient profile made in 1997 using Monaco EZ Color. And it's only got one rendering intent in it. I've never seen it before or seen it used, so I'm guessing that folder has been there for ages and just never got taken out.


Mike Adams
Correct Color
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Offline MaxGamut Posted 05-27-2016 - 07:58 AM
Post: #5
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21 Posts
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Onyx Version:
10
Printer(s):
HP L26500, Canon iPF9000

+1 for what Mike is saying.

Default profiles are for special cases where CMYK profile setting or profile itself is missing.

If you print CMYK pictures without embedded profile then default CMYK is used to calculate monitor preview. And if you print RGB pictures and media profile has no CMYK output profile - again default CMYK is used.

They are all very similar to standard device independent profiles (Gracol/Fogra/ISO) - this is the proof that they are meant to be input profiles.

The "compression" you are talking about is always the alchemy of rendering intent + gamut mapping. If you are after vivid colors (and your printer has nice big gamut) relative/absolute rendering intents will not give you better saturation (for CMYK data) - they need to simulate these standard input profiles (like Gracol or Fogra). And these standard profiles never are super-vivid - they represent an "average offset machine".
You have to look at Perceptual or at PosterColor.

In other words...
if you need super-vivid nice bright colors (=using whole printer gamut) and your printer really has big gamut, then:

a/ Standard CMYK data is probably "under-saturated" compared to you printer - you need the right rendering that will not simulate input CMYK. You need a rendering intent that can "expand" CMYK colors to your gamut.
Relative/Absolute Colorimetric will NOT MAKE IT as they only simulate standard CMYK colors of the input data!
Perceptual/Saturation/PosterColor can do the job.

b/ For big gamut printer one should always consider printing from RGB! Cool
RGB to CMYK conversion can use much more of the printer gamut. Especially for nice photos and vivid graphics. Of course, RGB data should be natively RGB, and not converted from CMYK. Grin
Then you can use Perceptual - compressing whole RGB gamut proportionally, or Relative - trying to simulate all RGB colors from neutral to vivid.

First method gives you nice detail and less saturation - all relations between colors are compressed and maintained, no colors are clipped.
Second method gives colors without compression, but only up to printer gamut. More vivid colors must be clipped at the gamut boundary - you will loose some detail here.
(like colors between 255/0/0 and 225/30/30 all will be converted to 0/95/95/0)

Numerically expressed: (very simplified)
Input Color: 1 2 3 4 5 6 7 8 9 10
Perceptual: 0.5 1.0 1.5 ... ... 4.0 4.5 5.0
Rel.Col.: 1 2 3 4 5 5 5 5 5 5


From my experience Relative Colorimetric is the method most customers want to see.
Near nobody can see the loss of saturation detail (it is the least obvious from Hue/Saturation/Brightness aspect. LOL
(This post was last modified: 05-29-2016 03:10 PM by MaxGamut.)
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Offline Pauly Posted 05-30-2016 - 06:48 AM
Post: #6
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109 Posts
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Onyx Version:
12.0
Printer(s):
Oce Arizona 480XT

Unfortunately i only have 1 printer i can use though onyx.. So i cannot to play with much larger gamut printer to see what onyx can do with it.

I understand where the lot of you are coming from.

I've also asked Onyx support cases. But i never seen to be able to get an answer, and when i do it's completely irrelevant.
I guess i'll not bother with onyx's ICC engine and stick to the i1P and in the mean time see what i can output from basiccolor. (more settings to tweak)
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Offline MaxGamut Posted 05-30-2016 - 11:39 AM
Post: #7
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21 Posts
Member

Onyx Version:
10
Printer(s):
HP L26500, Canon iPF9000

Pauly,

here is a scale I use for evaluating - it is a "boundary" of a CMYK gamut with 20% steps in hue and 10% step in channel value. You can assign any CMYK profile you normally use. Then convert to your output CMYK and look at the values.

If you use Relative Colorimetric Rendering you will see that many colors will get "dirty" with the third channel - GraCol/Fogra/ISO CMYK colors simply are not vivid enough. From the one ICC trial you have sent me once - your printer is capable of more saturated colors.

To demonstrate what I mean I added the same scale, but 2x converted to AdobeRGB (ISO Coated v2 to AdobeRGB):
1/ with Perceptual rendering ... in CMYK-to-RGB direction (=smaller to bigger gamut) Perceptual is expanding colors
2/ with Rel.Col. rendering ... colors stay approx. same as before - Rel.Col. does NOT expand color to bigger gamut.

All are the same colors, only the rendering indent was changed. You can print all 3 (same settings and rendering intent), and see what is happening.
(This post was last modified: 06-01-2016 12:51 PM by MaxGamut.)


Attached File(s)
.zip  Vivid Scale.zip (Size: 763 KB / Downloads: 18)
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Offline Pauly Posted 05-30-2016 - 07:01 PM
Post: #8
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109 Posts
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Onyx Version:
12.0
Printer(s):
Oce Arizona 480XT

Thanks for the chart. I've got a few ideas what i can do with it. I've used something similar but the smooth one supplied with onyx.
Might try turn it into a reference file.

I've done some soft proofing with it and works great! Really shows where onyx icc engine lacks in reproducing colours.
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Offline Correct Color Posted 06-01-2016 - 07:51 AM
Post: #9
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128 Posts
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Onyx Version:
10
Printer(s):
Epson

Max,

Just to point out...

The thing to keep in mind about rendering intents is that while their definitions were developed by the ICC, how they actually work in each ICC profile-making engine is not. That's developed by whomever made that particular engine.

And the difference between rendering intents in different profile-making engines is huge.

So huge that you can't make any generalizations about rendering intents without saying which engine made the profile you're testing.

Also, the purpose of rendering intents in general is to define how a profile will move out of gamut colors into gamut when it's moving from a larger color space to a smaller one.

And the ICC-defined purpose of perceptual rendering intent is to keep an image "perceptually pleasing" by eliminating clipping in out-of-gamut colors, which it does typically by moving all colors in the image towards the center of the gamut (basically, the white point.) Of course this is arbitrary, and different engines have different tools to do it, but many engines give the profile maker a great deal of latitude in how to define how perceptual does its job...

However, in no instance should its job ever be to expand outside of the gamut of the color space from which it's converting. Doing so would entirely defeat a good part of the purpose of color management to being with.

If you've actually tested this and know an engine that makes perceptual rendering intents that do that...

Well, myself, I wouldn't want to use that engine.


Mike Adams
Correct Color
(This post was last modified: 06-01-2016 08:03 AM by Correct Color.)
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Offline MaxGamut Posted 06-01-2016 - 02:59 PM
Post: #10
Member
21 Posts
Member

Onyx Version:
10
Printer(s):
HP L26500, Canon iPF9000

Hi Mike,
thanks for comments! Well, I know most of what you wrote here. Maybe, this is the start of a new nice deep discussion Wink:

...which it does typically by moving all colors in the image towards the center of the gamut (basically, the white point.)...
You mean grey axis, or ?

Also, the purpose of rendering intents in general is to define how a profile will move out of gamut colors into gamut when it's moving from a larger color space to a smaller one.
What do you mean with "larger color space to a smaller one in general"? Technically BtoA side of any ICC profile is just a huge table mapping all Lab colors to destination gamut. It does not know how the input profile managed the AtoB conversion to Lab space, and whether the source gamut was bigger than destination or not. Am I right? So you are stating that Perceptual when converting AtoB is acting like Colorimetric intent ? (preserving exact colors?)

If Perceptual and Saturation are not perfectly defined from ICC (Onyx PosterColor too), how could we know Perceptual is not expanding colors to Lab? At least white and black are expanded to white point and black point. OK, maybe I´m wrong with Perceptual, but...

However, in no instance should its job ever be to expand outside of the gamut of the color space from which it's converting. Doing so would entirely defeat a good part of the purpose of color management to being with.

... I have made tests comparing Perceptual and Colorimetric intent in ONYX, and Perceptual was always visibly more saturated! Even Onyx calls such setting with Perceptual rendering (in the quick ICC settings) a "colorful" conversion. Maybe... despite of what I think... it is all caused by different out-of-gamut mapping Perceptual vs Relative, but from what I saw - the differences are quite big. Printing CMYKtoCMYK from Fogra or ISO Coated makes stronger colors with Perceptual rendering! (and it should not!) Our printers have a slightly bigger destination gamut = 98% of source Fogra CMYK colors are in the destination gamut - they should theoretically not be moved. But they are!
Your explanation? Embarrased


Mike!
One new nice piece of knowledge I found when double-checking in Photoshop ! Eek!Suprised

FograCMYK-to-ourCMYK Relative Colorimetric is giving much worse colors if bigger differences in black point! Wow !!!! Interesting. Black Point Compensation (BPC) does the job !!!!!!!!!!!

I have a lot of experience when printing bigger to smaller CMYK gamut - lighter black point is usually giving very dark printouts with clipped black. Rel.Col.+ BPC corrects the overall lightness but makes colors a bit less saturated. But...
I never realized what is happening if black points are in the opposite position ! (source BP lighter than destination BP)
It looks like colors are somehow much weaker without BPC in such case!!! I.e. not mapping the black point down to destination black point colors is affecting colors in a strange way... Hmmm...
Yet another days of experimenting.... Cool
(This post was last modified: 06-01-2016 03:19 PM by MaxGamut.)
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