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kirkr5689
Inspiring
October 7, 2021
Question

No black ink CMYK profile looking as close to RGB as possible?

  • October 7, 2021
  • 3 replies
  • 621 views

Could somebody  share or create properly a CMYK profile where black would be staying white  after converting from RGB and CMY is looking   as close to sRGB as CMYK gamut could provide .  

  I just need black as a spare channel in evry layer and  the  black wouldn't be used in final color rendering . CMY need to be looking as they are regular RGB channels.          I did a few on my own in custom CMYK profile dialog  but neighter of them satisfy me, I see diffrent kinds of color shift with them   and I don't really understand  all the details there except zero black ink setting.  

Is there a special soft where I could do such artificial, weird profile  if Photoshop is just uncappable?

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3 replies

T
Test Screen Name
Legend
October 8, 2021

A shared CMYK profile would be useless with you. You are assuming that CMYK inks are generic, but they are not! You need a custom profile made for YOUR CMYK situation, but made with zero "undercolor removal". This seems very specialist indeed. Bear in mind the starting point for any CMYK profile is hardware to analyse the inks and paper result. 

    c.pfaffenbichler
    Community Expert
    c.pfaffenbichlerCommunity Expert
    Community Expert
    October 8, 2021

    I think the OP is talking about a »theoretic« CMYK Space, with C, M and Y behaving exactly like R, G and B of sRGB and completely divorced from an actual printing process. 

    Stephen Marsh
    Community Expert
    Stephen MarshCommunity Expert
    Community Expert
    October 8, 2021

    Agreed, one should really read the previous topic linked in my first post for the background, then carefully read the comments in this thread before replying.

    Stephen Marsh
    Community Expert
    Stephen MarshCommunity Expert
    Community Expert
    October 8, 2021

    @kirkr5689 

     

    Hoping for a different answer?

     

    https://community.adobe.com/t5/photoshop-ecosystem-discussions/cmy-minus-k-of-cmyk-channels-be-looking-like-rgb/td-p/12068052/page/2

     

    OK, I'll provide a different answer than last time.

     

    I undertstand that this is not for printing/prep, you are wishing to make use of the K channel for RGB editing, so that the K acts like a layer specific alpha and not document specific.

     

    1) RGB - Image/Mode/Multichannel (the RGB channels will not be modified)

    2) Add a new white alpha, so that there are now 4 channels, 3 with content, one without

    3) Image/Mode/CMYK

    4) Edit/Assign Profile the following synthetic CMYK profile that is not a standard press description, it is based on Adobe RGB 1998 primaries:

     

    https://curvemeister.com/downloads/

    https://curvemeister.com/downloads/wgcmyk/wgcmyk_gcr_light_b85_11-14-01.zip

     

      c.pfaffenbichler
      Community Expert
      c.pfaffenbichlerCommunity Expert
      Community Expert
      October 8, 2021

      Well, no wonder this issue seemed familiar … that the old thread was authored by the same poster surprised me, though. 

      c.pfaffenbichler
      Community Expert
      c.pfaffenbichlerCommunity Expert
      Community Expert
      October 8, 2021

      Photoshop is not a dedicated ICC Profile-creation program and its »Custom CMYK« is old, way old, and has not been improved for a long time. 

      You may want to do a serach for something like »icc profile creation software«. 

       

      I think I vaguely remember a similar thread from a while ago, but I couldn’t find it. 

       

      How do you intend to get the C, M and Y channels back into R, G and B? Via Multichannel? 

      What is the task anyway, what do you need the additional Channel for? Could deactivated Layer Masks work? 

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