Remove cyan in CMYK. But it is still there in the PDF

[tommy.bonte]

Hi, short brief

Work in Photoshop

source: Coated FOGRA39 (ISO 12647-2:2004)

Exclude Cyan with Channel Mixer

embed profile, place it in Illustrator

Illustrator set for:

CMYK - mode

Source: Coated FOGRA39 (ISO 12647-2:2004)

Preserve Numbers (ignore linked profiles)

Conversion: relative colorimetric (Adobe CMM)

Output: Convert to destination (preserve numbers) = 0.7% Cyan pops up like sprinkle in the areas where i only wan´t tones of magenta, yellow or black

Output: No Conversion = 0% Cyan, like it should be

Set "Off" for "color management policies" = not working

Drop embedded imaeg profile = not working

Question:

Why isn´t "preserve numbers" honored when I save my PDF?

Since I´ve troubledshoot ALOT around this and I´ve googled as much as I possibly could. I only have a few guesses left;

a. I have wrong, the option "Convert to destination (preserve numbers)" still process images even though Illustrator "Ignore linked profiles"?

b. GPU - performance for CMYK-mode in Illustrator is still a beta?

Thanks for your time. If your interested in the topic I can always give you more info. If you have a clear answer PLEASE write

[Test Screen Name]

How EXACTLY do you determine that the PDF contains data in the cyan channel? Please describe your method and settings.

[tommy.bonte]

Measure with Output Preview in Adobe Acrobat or FlexoPrint view in Esko Viewer

[tommy.bonte]

Made a video this morning. Kids and wife around, so no sound

[Mike_Gondek]

I am not familiar with FOGRA profile could it be LAB or RGB? Check by clicking show in Acobat output Preview, to see RGB elements. In my example I used the smallest file size preset which covert times to RGB, hence my 100% cyan is 69 15 0 0 .

[tommy.bonte]

Thanks Mike but Fogra is a CMYK profile

[Mike_Gondek]

Try US Web SWOP Coated, to confirm this is coming from your Fogra profile.

My Deutsch ist nicht gut, but yours may be better try https://fogra.org/..

[tommy.bonte]

Hi Mike, I will try Swop. When I test my own profiles the same problem occur. So this isnt Fogra specific. I use the Fogra profile as and example.

[Lukas Engqvist]

Tommy who posted this and I work close, but as this is a discussion I think that is current since involuntary colour management is a big issue we will let the community benefit from the public discussion.

This problem is related to one which has been frustrating artists that are getting involuntary conversion of 100% K when texting comics. Unfortunately not having ability to measure the % values in Adobe Illustrator is a big handicap for trouble shooting.

When working with CMYK and you want to be sure no colours are converted make sure that you turn all warnings on for mismatches. When placing a PSD that has a missmatch in profile you will get the option to discard the profile. (sorry it's in swedish)

In Illustrator there are several profiles in play: the ICC from the PSD file, the working CMYK and the document CMYK, you can also mess things upp further by specifying a different profile in your PDF settings.

"No Conversion" in PDFx4 means each object will have it's ICC embedded, objects are tagged but not converted.

In Acrobat again there is the objects individual ICC profiles (that can be cleaned by decalibrating objects), The output intent ( for PDFx labeled "Output Intent: NameOfProfile") and the Simulation profile.

Even if I favour PDFx4 for the layer structure I prefer the PDFx4 with CMYK conversion for jobs such as this. All objects preferably to be device CMYK (decalibrated) and the only ICC to be the output intent (+ spot colours if appropriate). This prevents surprises with blend modes, transparency etc.

In the case of a transparent PSD there could also be a certain % cyan in the edges of the transparent PSD, because of antialiasing and/or compression of the image and its mask generating a garbage contour. Only way to be sure not to get this is to make sure that there is no resampling of the artwork.

[tommy.bonte]

It is not impossible that this is an Illustrator error. As pointing out in video, to keep track, there should be 0% cyan. Using no conversion should be and option since it honors object and image source. This makes it an obligation.

[Monika Gause]

Have you made sure you're suing the same version of the FOGRA profile everywhere?

There has been an incident with different versions of FOGRA profiles (I'm not referring to FOGRA 27 and 39, but different versions of one of them). I don't remember exactly which one it was and couldn't find the forum discussions anymore, but might be worth checking.

[tommy.bonte]

Hi Monica, are you referring to ISO or TAC 300 profiles of Fogra 39? Im a 100% sure its the same. Doublechecked now aswell.

[Mike_Gondek]

What is your destination profile.

[tommy.bonte]

Destination profile or Intent is the same Fogra profile

[Test Screen Name · Accepted solution]

It's a very small change. I wonder if it's a JPEG compression artefact. Can change compression to ZIP on export to check.

[tommy.bonte]

WOW ... it clearly has to do with something like this! This also explains the unregularity after the screening process. I´ve tested different jobs, made other adjustments in Photoshop and doublechecked in three different softwares now, the value of cyan is 0. It works!

It´s an solution. Definately. But what still upsets me is that I haft to "modify" the standard.

Thanks alot Screen Name. I put your answer as a correct answer. And thanks to everybody else who tried to help me with this!

[Lukas Engqvist]

If it was a JPG artefact that also explains why PDFx1 was getting more artefacts than PDFx4 since it has more stitching. Well done "Screen Name"