9 Replies Latest reply on Mar 2, 2013 5:38 AM by Sinoseps

    Embed color profile for Spot Multichannel

    Sinoseps Level 1

      Is it possible to embed a color profile into a multichannel file made up of spot colors onlys ? More specifically can you embed custom dot gain curves into such file like you can for other color spaces like CMYK. ?

        • 1. Re: Embed color profile for Spot Multichannel
          John Danek Level 4

          I believe your Color Settings would be honored in the file.  So, if you have a 20% dot gain compensation, it will be in the spot channels which I also believe follow whatever grayscale settings you have in place.  I would also recommend saving the file as an .eps; but that's just me.  You can save your file in whatever format you want, color info should go with it.

          • 2. Re: Embed color profile for Spot Multichannel
            Sinoseps Level 1

            Hi John

            thanks for input. 

            However when I try and save the multichannel document the save colour profile is greyed out and it wont let me select it. Which suggests to me the dot gain is not embeded.


            Also if I re-open the file with different ink settings ie custom dot gain in spot working space in photoshop, no profile mismatch warning window comes up and the file is displayed with the current settings, so look wrong.


            My greyscale settings are set to gamma 2,2, but as this is in multichannel format will this setting be relevant?




            • 3. Re: Embed color profile for Spot Multichannel
              John Danek Level 4

              I still believe your settings will go with the file.  Try not to rely too much on the appearance of the file.  Profile or no profile, you probably wouldn't be able to detect a visual difference on-screen.  I set all of my apps at 1.8 gamma; the difference in gamma between 1.8 vs. 2.2 may be brightness on the monitor.  I am a print based studio, so I prefer 1.8; but it should not matter if you use 2.2.  Remember, your file still has to be processed via whatever output device you are planning for.  Spot channels should act similar to grayscale files when printed.  If you have some type of proofing device that has a RIP assigned to it, you could do a test with different settings to see how the files print and if there are any noticable differences between different settings.  If not, try contacting whoever you plan on using for output and see if they can RIP the file(s) and do an interim proof for you.

              • 4. Re: Embed color profile for Spot Multichannel
                Sinoseps Level 1

                Hi John

                thanks allot for you quick input on this its much appreciated.  


                Ive since found out for sure from a Photoshop programmer that it currently does NOT support multichannel profiles as there are allot of details to be worked out in the standard and the code. 


                Im sure spot channel custom dot gain curves are honered and embeded when a spot channel is part of other color spaces such as CMYK or Greyscale, or why have the  curves in the first place.

                Maybe someone can clarify this ?


                John maybe you could clarify for me why we would use a gamma setting for greyscale instead of an actual dot gain curve if we know a dot gain value. ???

                • 5. Re: Embed color profile for Spot Multichannel
                  John Danek Level 4

                  I'm not sure why you are concerned with gamma.  As far as I know and understand, gamma is a setting for display attributes.  So, if you are using 2.2 on your CPU, images may appear more inline with video graphics ( gaming and internet protocols ).  I my case, 1.8 fits better in a print workflow and color falls more inline with output characteristics and expectations.  I am not sure if gamma setting affects dot gain at all.

                  • 6. Re: Embed color profile for Spot Multichannel
                    Sinoseps Level 1

                    Thanks john. I'm not concerend with gamma as such, I just want to get the settings right.  As Dot gain and gamma are in the same drop down menu of the grey working space I was thinking they must be related ?

                    If you new you had a 30% dot gain for a greyscale image would you change the custom dot gain setting in grey working space or leave it as gamma 1.8 or 2.2 ?


                    Just trying to get me head round all this.

                    • 7. Re: Embed color profile for Spot Multichannel
                      Level 7

                      Gamma applies to any image encoding, not just displays.


                      Dot gain is similar to a gamma encoding.

                      • 8. Re: Embed color profile for Spot Multichannel
                        John Danek Level 4

                        As far as I know, there is no connection or relation between gamma and dot gain.  However, if your workflow excludes print media, you do not have to indicate any type of dot gain and, therefore, can assign a particular gamma to your "video" intended image ( i.e., television graphics, powerpoint oresentation files, etc. ).  So, if you knew you are heading for a 30% dot gain ( i.e. offset press, magazine or newsprint, etc. ), then assign it in the working space dialog in PS. Again, this is my interpretation of gamma vs. dot gain.  Once you understand the dynamics of the working space ( i.e., what you typically work on day-to-day )), then it sort of makes sense.  I suppose if I were to suddenly be assigned to work on a video graphics project, I could change my gamma and eliminate dot gain because there is none.  I'd just have to remember to go back and re-assign dot gain for my print projects.  If, for instance, I was chosen to design a logo graphicv for a TV news program, perhaps a gamma of 2.2 would help the appearance of the color's brightness on screen.  It comes down to the final application of the file itself.  That's my take on it.

                        • 9. Re: Embed color profile for Spot Multichannel
                          Sinoseps Level 1

                          Thanks for your input john much appreciated, and thanks Scott. 


                          My work flow does involve printed media. Screen printing to be precise, where dot gains can be very large depending on the inks and print method. Sometimes around 30-40%.  


                          Ive had a issue with mutltichannel separations Ive sent not looking correct on other poeple computers as their settings dont include the higher dot gain settings, and no profile mismatch warning has been given by photoshop.  Meaning the values were not embeded in the files ive sent.  Ive always thought they would be embeded as ive been told before they would. However now know different.  



                          I guess now I need know if dot gain values will be embeded for spot channels if they are part of a greyscale file ? 

                          If so then great I can just keep my spot seps as greyscale instead of multichannel.