Incorrect RGB to CYMK conversion CorelDraw

Incorrect RGB-to-CYMK conversion CorelDraw has not properly managed RGB-to-CYMK conversion for many years, losing a lot of color information, even in images where the color gamut is safely within the CYMK range. The same conversion is done correctly by photoshop instead. The Coreldraw color manager is configured with the same color profiles as Photoshop, but in any case the image is treated differently. The ICM CMM color setting is the correct setting to use. The others produce the same effect. 


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  • Interesting, first off, I do not read your language, but I believe I can muddle through, you have your color management setting a bit off tilt in both applications.

    text color backgrounds with gamma is the translation that pops up with this 

    Not sure of this is a correct translation but I question anything with a 1.45 GAMMA. Can you describe what you intend by setting this please?

    Some basic concepts first, the terms right and wrong can only be assigned to technical errors.

    Conversions can be wrong if they induce technical errors such as clipping, (posterization) however a technically correct conversion cannot be right or wrong. It's an artistic choice, we can agree or disagree with it, but it is neither right nor wrong. In your case you misinterpret a different conversion in Draw from Adobe as wrong, however looking at your color management settings you got exactly what you ask both applications to do.

    BACKGROUND first.

    First thing to remember is that due to the limited support of color engines in Adobe exact matching is not possible, Adobe (as far as I can find out) does not support the WCS (Windows Color System) as a color engine in their applications, Adobe (as far as I can tell) has never upgraded their standalone ACE color engine application for 64 bit so you cannot use it, and I'm guessing here, in applications that do not pay Adobe a fee for using it. So, no ACE for Draw.

    Second thing to remember is that Adobe use a non-ICC compliant color process.  Their default setting of relative colorimetric rendering intent with Black Point Compensation is NOT ICC compliant.  Their Black Point Compensation process was created years ago because of malformed profiles that did not address the black point in the profile.  Black Point compensation mimics perceptual rendering and using it solved a few issues, the malformed RGB profiles from the early 90's, the need to address the constant misreading of the definition of the relative colorimetric rendering intent by the public.

    Unfortunately, this has been addressed over 15 years ago in the profiles and modern profiles creation applications and is no longer needed, but Adobe has not changed this default setting and in my opinion, it provides a marketing advantage for them in with those who are not color management savvy. READ: we constantly get questions like that my files don't look like my Adobe files and the erroneous statement that Adobe is right.

    The ICC has stated on their web site that relative colorimetric rendering was created for conversion from equal sized color spaces.  It was never intended for RGB to CMYK conversion and in fact is useless for that purpose.  As of the last time I went to the ICC web site they have not accepted Black Point Compensation as an ICC compliant workflow.

    Fortunately, users have some viable choices for solutions.

    If you are a multi-application user, you need to coordinate your color management settings between the applications as much as possible.  This again comes back to what is technically right or wrong and what is an artistic choice.

    Technically incorrect, non-ICC compliance, any concept that Adobe is always right. Using Black Point Compensation is wrong.

    Compromises: ICC compliance is not 100% compatible with expected uses of CMYK to RGB conversions in the GDI (graphic device interface, non-postscript) workflow.  In short K100 does not convert to R0, G0, B0 unless you force it in your color management settings. A can of smelly worms but a discussion I'll have if you feel masochistic.

    Neither an asset nor a liability but some facts:  In Windows since Vista all display is rendered using the Windows Color System, (WCS). IT DOES NOT MATTER what you use in your application Windows only uses WCS.

    When selecting the WCS as your color engine in CorelDRAW, WCS handles all RGB to RGB color conversions, MS ICM CMM 3 handles all RGB or Spot Color conversion to CMYK. The above statement is why I use WCS as my color engine of choice.

    When selecting MS ICM CMM as your color engine in CorelDRAW, MS ICM CMM3 handles all RGB to RGB and all CMYK conversions. Yes, this will produce slightly different RGB to RGB conversions than using WCS.  Again, not right nor wrong, just a choice.

    Windows only supports two white points, 5,000 and 6,500 Kelvin, PERIOD.  Both are industry standards.

    The three rules: Use, Assign and Convert.  I wrote about these in my first book, when you open files, you use the embedded profiles.  When you import files, for RGB and grayscale content you convert to your document, with CMYK content you assign to your document CMYK profile to avoid CMYK color shifts and major grey balance transition shifts.

    The rules of CMYK: The reason you assign CMYK content to your document CMYK profile is that CMYK is an absolute color space.  Meaning that the CMYK numbers mean the same in any CMYK color space as a source number set. Only the gray balance transition is different. In output all CMYK is treated equally and converted the linearization, ink limit dot gain curve/media profile of the output device.  CMYK conversion, profile creation and assignments are another can of smelly works but a discussion I'll have if you feel masochistic.

    Your Draw settings:  On importing your converting your CMYK content, that's incorrect you should be set to assign.  Also, your using true relative colorimetric rendering which is incorrect.   Your converting spot color to CMYK instead of LAB, LAB has been the standard for well over a decade but it's your choice it may work for some old jobs you have.  Your color engine choice is the one that is the farthest from ACE available to you.

    Your Adobe Settings: I can't tell if your open settings and import setting are different, but the opening controls look like use profile. I don't see any settings that look like import controls.  You're using relative colorimetric with black point compensation turned on, that's not ICC compliant and cannot be matched and in fact is incorrect. Text color with gamma I don't get it.

    Suggestions:  Make screen captures of all your current CorelDRAW and Adobe color management settings in case you need to reset.

    Create some RGB test images if you don't have any, I can send some.

    CorelDRAW: Change current CorelDRAW default color management settings to perceptual renderings, select WCS or LCMS as your color engine, (try this on test images against Adobe ACE engine). For the import controls set CMYK to assign document profile.  Name and save these custom settings.

    Adobe: Match the settings in Adobe to those used in CorelDRAW. MOST IMPORTANT, rendering intent to perceptual, and the assign document profile for CMYK for import.  I would leave ACE as the color engine.  Name and save your settings.

    Try some test images, this will be as close as you can get, the only differences will be caused by the different color engines.

    I do not use MS ICM CMM for my engine as the RGB conversions are not appealing to me.

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