9 Replies Latest reply on Jun 11, 2009 10:00 AM by Lou Dina

    CMYK to Grayscale back to CMYK

    Shawn Tester Level 1

      Hello,

       

      I have an image for a client that is a shot of a neighborhood. The image was meant to be in black and white except for the sidewalk which is in gold. The issue is that the image is not in black and white and when the image prints on an iGen it picks up Magenta in the clouds and other areas.

       

      Here is my question:

       

      Is there a way to convert a CMYK image to grayscale (monocrome). Take the values and populate the "black" channel of cmyk, using photoshop?

       

      Thanks

      Shawn

        • 1. Re: CMYK to Grayscale back to CMYK
          Lou Dina Level 3

          Shawn,

           

          Is your gold ink a spot color, or a CMYK build?

           

          If a CMYK build, you could convert to CMYK using Max or Heavy GCR.  This will give you a heavy black plate and keep your black components neutral, but allow your gold to be color as intended.  You can use Photoshop's custom CMYK, which isn't ideal, but will work okay for a simpe image like this.  If you have profiling software, you can build a heavy or max gcr profile.  I would do it for you, but my computer HDD crashed yesterday (typing this from a laptop that doesn't have the software loaded).

           

          Lou

          • 2. Re: CMYK to Grayscale back to CMYK
            Shawn Tester Level 1

            I figured it out. We played with channel mixing in photoshop and fixed the issue.

             

            thanks

             

            Shawn Tester

            GRV Premedia

            614-801-4775

             

            P Please consider the environment before printing this email

            • 3. Re: CMYK to Grayscale back to CMYK
              Gusgsm Level 2

              A very simple way of passing all the information of a CMYK greyscale to the black channel is using "Tone/Hue" with "colorize" checked on and "saturation lowered to maximun".

               

              That sends all the pixels howling to the Black channel.

              • 4. Re: CMYK to Grayscale back to CMYK
                Lou Dina Level 3

                Gustavo....como estas?  I hope you are well.  It's been awhile.

                 

                regards, Lou Dina

                • 5. Re: CMYK to Grayscale back to CMYK
                  Larry Tseng Level 1

                  Gustavo,

                   

                  My more complicated, but color-managed, procedure goes like this: (a) extract a grayscale profile from the cmyk profile with Photoshop, (b) convert the colorful cmyk image to this grayscale profile, (c) paste this grayscale image to the black channel of a blank cmyk Photoshop document.

                   

                  Cheers,

                   

                  Larry

                  • 6. Re: CMYK to Grayscale back to CMYK
                    Gusgsm Level 2

                    Hi, Lou. Quite nice, thanks. Hope you're well too over there.

                     

                    I wonder (no time now to test it) if the three ways indicated here would produce the same results. I guess the answer is 'yes' but, as a side note, I think the "maximum CGR way" is the best approach to pass colour screen grabs into CMYK, the Tone/Hue is the easiest one (easily automatizable) and the copy-paste into the black channel is... just another way.

                     

                    Best regards.

                     

                    Gustavo posting from a rather Sunny Madrid

                     

                    PS. Larry, I see you and I registered here just the very same day. Odd coincidence, isn't it?

                    • 7. Re: CMYK to Grayscale back to CMYK
                      Lou Dina Level 3

                      Gustavo,

                       

                      Hot and humid here in Birmingham, AL.  I loved Madrid when I was there many years ago. I bought a hand made classical guitar there from a man named Marcel Lopez Nieto.  I wanted to buy one from Aguado, but it was too expensive for me.  Both men must be long gone by now, but they were excellent luthiers.

                       

                      My PC crashed and I ordered a new Mac.  When I receive it, set it up and figure out how to use a new O/S, I will probably experiment with all the methods in this thread.  It's always fun to learn new approaches and methods.  It may be a few weeks.  Right now, I am stuck on a little laptop, no Photoshop, no toys at all.    But I have new toys coming which will be fun. 

                       

                      Best to you,

                       

                      Lou

                      • 8. Re: CMYK to Grayscale back to CMYK
                        Larry Tseng Level 1

                        Gustavo,

                         

                        Yes, that does seem to be quite a coincidence. I also wonder about Lou's registeration date though: to me, he's been around since the beginning of time.

                         

                        Larry

                        • 9. Re: CMYK to Grayscale back to CMYK
                          Lou Dina Level 3

                          Hi Larry.  Yeah....I think that date may be incorrect.  BTW, being old is nothing in particular to crow about!  It's called persistence and stubbornness. 

                           

                          Lou