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rémyn60562362
Participant
January 27, 2021
Answered

Apply UCR / GCR

  • January 27, 2021
  • 2 replies
  • 6582 views

Hello,

Our printer asks us :

It is advisable to apply UCR / GCR if you include 4 colour black and white images. We also suggest to strengthen any black elements (backgrounds) with an addition of 40% CMY. Black elements must be set in overprint.

Does anyone know how to apply UCR / GCR then 40% CMY?
(keeping the profil ISO Coated V2 300)


Thanks you !

 

This topic has been closed for replies.
Correct answer Stephen Marsh

The following high GCR version will help when converting from RGB, however, if you really feel that you require a specific CMYK build, then you will need to make post-conversion edits:

 

https://www.colormanagement.org/en/isoprofile.html#coated_FOGRA39_GCR_bas

 

https://www.colormanagement.org/download_files/coated_FOGRA39_GCR_bas.zip

 

(Fogra39 and ISO Coated v2 are pretty much identical, they are both for the same condition, however, some profiles may have very minor differences which are not worth fussing over)

2 replies

Stephen Marsh
Community Expert
Stephen MarshCommunity ExpertCorrect answer
Community Expert
January 28, 2021

The following high GCR version will help when converting from RGB, however, if you really feel that you require a specific CMYK build, then you will need to make post-conversion edits:

 

https://www.colormanagement.org/en/isoprofile.html#coated_FOGRA39_GCR_bas

 

https://www.colormanagement.org/download_files/coated_FOGRA39_GCR_bas.zip

 

(Fogra39 and ISO Coated v2 are pretty much identical, they are both for the same condition, however, some profiles may have very minor differences which are not worth fussing over)

    D Fosse
    Community Expert
    D FosseCommunity Expert
    Community Expert
    January 28, 2021

    Side note: The differences between FOGRA39 and ISO Coated aren't all academic: Ink limits are 330% and 300% respectively. I don't know if those 30% will cause actual ink smearing on presses calibrated for ISO Coated, but it's not something I'm inclined to experiment with.

      Stephen Marsh
      Community Expert
      Stephen MarshCommunity Expert
      Community Expert
      January 28, 2021

      Note that ISO Coated and ISO Coated v2 are NOT the same thing. The Fogra39L characterisation/measurement dataset forms the basis of both ISO Coated v2 and the various Fogra39 based colour profiles provided by many different vendors. They are both for the same ISO 12647-2:2004 printing condition, however, different profiles can indeed deliver different total ink values. For some profiles, perceptual and relative colorimetric rendering intents deliver different total ink values. The "coated_FOGRA39_GCR_bas.icc" profile should deliver under 300% total ink limit for both relative and perceptual rendering. If creating solid panels of rich black (as opposed to photos) then a post conversion tweak to bump up the K channel from 97-98 to 100% may be in order to match elements in page layout software for example.

       

      All that being said, the "coated_FOGRA39_GCR_bas.icc" will not deliver a total ink of 40c40m40y100k (220% total ink), but it will create more stable neutrals. To get closer to that value, the "ISOcoated_VIGC_39L_220_v2.icc" would be a good choice, however it would still require post conversion editing to hit the "ideal" 40cmy100k values requested.

       

       

       

        NB, colourmanagement
        Community Expert
        NB, colourmanagementCommunity Expert
        Community Expert
        January 28, 2021

        Hi rémyn60562362,

        I think the only way to do this properly is to rebuild the ICC profile with the setting you need.

         

        I can do this within basICColor Print 5 which will open the profile, extract the "training data" (which was used to make ISO Coated V2 300.icc) and allow the building of a new profile with user-selected settings. 

        Alternatively, download the FOGRA 39L data and make a new profile using your ICC output profile building application - setting black generation and ink limits as you desire. 

        You can contact me by message if you need help with this. 

         

        DO NOT be tempted to use Photoshop's Edit ICC interface, it's not going to do what you expect at all. 

         

        Myth #23: Photoshop's color setting dialog lets you edit an ICC CMYK profile.

        This one's from a conversation I had with color management icon Don Hutcheson the other day.
        There are two methods for setting up the CMYK working space and CMYK conversions in Photoshop and unfortunately Adobe has not made the distinction very clear so there's room for confusion.
        First, the legacy CMYK system that has been around for many many versions is pre-ICC and is available when you choose "Custom CMYK..." in the CMYK popup of the Color Settings dialog. These CMYK setup options allow you to select ink color values, black generation, dot gain and other parameters. Once selected, Photoshop creates a simplified ICC profile that does not contain a paper white value and also only contains the colorimetric rendering intent.
        Any other profile selected is a true ICC profile that is used by the Adobe ACE CMM to perform color transformations.
        What's the difference? Well, the most important thing is that these are very different methods of setting up CMYK conversions and the older engine, while it has lots of options, produces conversions that are fairly crude and not up to today's standards. Another point is that the settings you see in the Custom CMYK setup area have NOTHING to do with the current or previous ICC profile. It's easy to get drawn into thinking that you can select a modern profile and then alter the profile's settings in the custom area. This is not the case however.
        We urge you to use modern ICC profiles for your CMYK setup. if you feel you want to change the separation settings (which is understandable) then generate your own ICC profiles (in a profiling application) using your desired settings and then select them in Photoshop. Photoshop is not a profile editor and the only profiles it can generate are based on old technology and not enough color data to give quality results.

         

        from: http://www.colorwiki.com/wiki/Color_Management_Myths_21-25#Myth_.2323:_Photoshop.27s_color_setting_dialog_lets_you_edit_an_ICC_CMYK_profile.

         

        I hope this helps
        neil barstow, colourmanagement net :: adobe forum volunteer
        google me "neil barstow colourmanagement" for lots of free articles on colour management
        [please only use the blue reply button at the top of the page, this maintains the original thread title and chronological order of posts]

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