7 Replies Latest reply on Apr 27, 2013 10:02 AM by thedigitaldog

    How to select matching RGB and CMYK colors

    rgreen001 Level 1

      Starting from scratch for a client, how do I select matching RGB and CMYK pairs?

       

      Say we find a nice red colour in RGB for screen use, how do I then find the correct CMYK for print? And what assumptions do I have to make when doing this, if any?

      Would it be the same for the other way around (choose CMYK first for print and then find the RGB equivalent)

       

      Is it more sensible to start with a Pantone colour and then find the RGB and CMYK equivalents for that?

       

      Many thanks

      RobbieG

      (I'm working with Ai, Ps and Id CS6)

        • 1. Re: How to select matching RGB and CMYK colors
          thedigitaldog MVP & Adobe Community Professional

          rgreen001 wrote:

          Say we find a nice red colour in RGB for screen use, how do I then find the correct CMYK for print?

          You need the correct ICC profile that defines the print conditions used. Anything but that correct descriptor is simply an assumption.

          • 2. Re: How to select matching RGB and CMYK colors
            rgreen001 Level 1

            Thank you. I'm sure you are trying to be helpful but...

             

            You know, I'm not sure if I understand what you mean by the correct ICC profile that defines the print conditions used

            • 3. Re: How to select matching RGB and CMYK colors
              Level 5

              In addition to guru Andrew Rodney's on-target comment, you should also keep in mind that the CMYK color space is much, much narrower than just about any flavor of RGB, so there will be RGB colors that are totally outside the gamut of printable colors in CMYK.

               

              For more on print target profiles, start learning about color management here:

               

              http://www.gballard.net/psd/cmstheory.html

              • 4. Re: How to select matching RGB and CMYK colors
                Level 5

                The correct printer profile will be specific to the printer, inks and paper that will be used for printing the image in question.

                • 5. Re: How to select matching RGB and CMYK colors
                  John Danek Level 4

                  Yes.  Better to start with Pantone reference books where you are viewing the color in a reflective environment.  As already mentioned, color on the monitor can be deceptive.  And, I think the others are basiclt saying that you should have everything calibrated and use color management policies in your apps.  There is a way to find CMYK equivalents using Photoshop's color palette.  Let's say you have an RGB Red as the foreground color in Photoshop.  If you double click on the swatch you will get Photoshop's color palette which lists the RGB percentages, CMYK percentages, LAB percentages, and HEX web color for that Red.  You can go further and select "Custom" and the Pasntone Spot color palette opens and gives you the closest Spot color value for that Red.  This however, depends on your color settings.  That's why I recommend you start with the Pantone swatch book and get the perecentages of CMYK from their formula guide which is set to industry standard color.

                  • 6. Re: How to select matching RGB and CMYK colors
                    rgreen001 Level 1

                    Thank you John, station_two and Andrew.

                     

                    So what you are saying, I think, is that it is not possible to determine an RGB and CMYK colour pair unless you know the particulars of the the printer, ink and paper you are printing to and that the monitor has been calibrated.

                     

                    Until then, it will all be an aproximation.

                     

                    The link from station_two is really useful. Thank you for that.

                     

                    KInd regards

                    RobbieG

                    • 7. Re: How to select matching RGB and CMYK colors
                      thedigitaldog MVP & Adobe Community Professional

                      rgreen001 wrote:

                      So what you are saying, I think, is that it is not possible to determine an RGB and CMYK colour pair unless you know the particulars of the the printer, ink and paper you are printing to and that the monitor has been calibrated.

                      Yes in terms of values for output. You could work on a B&W display and the proper numbers will still result, that's what the ICC profiles do. But yes, ideally the display would be part of this operation and that would require it be calibrated and profiled.