5 Replies Latest reply on Jan 6, 2013 12:07 AM by station_two

    LAB Swatches produce different colors in ID, PS & Illy

    MarieMeyer Level 1

      Hello. I have CS4 and have sychronized the color management settings. I have a set of swatches in .ase format that were defined as LAB process colors. When I load them into InDesign, Photoshop and Illustrator they all three produce different CMYK values - differences large enough that they can't be the result of rounding errors. This surprises me given that I've sychronized the color management settings. Do each of these three programs use a different formula/set of instructions for LAB>CMYK conversion?

        • 1. Re: LAB Swatches produce different colors in ID, PS & Illy
          Gernot Hoffmann Level 3

          Hello,

           

          I'm not sure about, but I would define the Lab swatches not as Process colors

          but as Spot colors. This is definitely necessary for a consequent treatment

          as Lab colors.The whole file can be converted to CMYK by Acrobat Pro,

          using a well defined CMYK profile at this stage.

           

          Best regards --Gernot Hoffmann

          • 2. Re: LAB Swatches produce different colors in ID, PS & Illy
            Printer_Rick Level 4

            Try this to verify your synchronization:

             

            1. Make brand new documents in all 3 programs (just for testing). In Illustrator and Photoshop, they need to be in CMYK mode.

             

            2. Load the swatch into these brand new documents. Check to see if the swatches are spot or process in InDesign and Illustrator. It will automatically come in as process in the Photoshop CMYK image.

             

            3. In InDesign and Illustrator - does the new swatch have a Lab icon? If it doesn't, then the color is not defined as Lab in the .ase.

             

            4. In CS4, Pantone libraries default to CMYK definitions (the legacy Solid to Process recipes). Is it a Pantone Solid library? If so, the color would import as spot, with a CMYK icon. To access the Pantone Lab definition, both Illustrator and InDesign have a drop down menu option in the swatches panel. In AI, "Spot Colors..." In ID, "Ink Manager".

             

            5. Unfortunately in Illustrator, to check the CMYK breakdown, you have to change the swatch color mode to CMYK. (Side Note - in a normal workflow, if you plan on placing an AI file into ID, I recommend retaining a spot Lab definition in Illustrator - the color can be repurposed by InDesign if necessary).

             

            6. In InDesign, Ink Manager, select "Use Standard Lab for Spots." Then, (still in the Ink Manager) just to the left of the Lab spot color, click the spot icon to change it to process (it will look like CMYK in the Ink Manager dialog). Once you exit the ink manager, notice that in the swatches panel, the swatch still has the Lab icon. (I recommend using the ink manager to change any spot color to process in InDesign. It is much better than changing the swatch definition).

             

            Once you have checked the CMYK breakdown in all 3 programs, in the brand new documents, they should all match. If they don't, post back. If they do, then the original mismatch is because of color space differences in the pre-existing documents. Post back we will go from there.

             

            Let me know if this helps. Color managing swatches can be confusing to say the least.

            1 person found this helpful
            • 3. Re: LAB Swatches produce different colors in ID, PS & Illy
              Gernot Hoffmann Level 3

              Make a Spot swatch in Lab Mode in an RGB or CMYK doc in Illustrator

              (not as Process swatch, not in RGB, not in CMYK)

              Save as PDF

               

              Oben doc in Photoshop in  Lab mode

              Measure Lab values - they are the same as in Illustrator.

               

              Place doc in InDesign

              InDesign doesn't change Lab numbers in placed graphic.

               

              So far it´s guaranteed that Lab values are preserved across the three programs.

               

              The appearance depends on local color settings and gamut clipping issues.

              Even if the color settings should be globally the same - there are local settings,

              like the document color mode in Illustrator. Which settings RGB or CMYK are

              correct for Lab docs? No idea, I'm not bothering about appearance in this case,

              because there is another ugly problem already luring: gamut clipping.

              A Lab or Spot can be in-gamut or out-of-gamut for a specified RGB space and

              specified CMYK-space.

              Spots by Lab values which are definitely in-gamut or out-of-gamut for sRGB

              resp. ISOCoatede-v2(eci) are found here:

               

              http://www.fho-emden.de/~hoffmann/munsell15052009.pdf

               

              If we choose Spots with values in-gamut for sRGB, then we have good chance

              that they will appear identical in all three programs. 

               

              The whole workflow shouldn't be confused by early conversions into a CMYK

              space. A ready PDF, still with Lab colors like the mentionend one (except for

              text and line black/gray, which is in CMYK K-only) can be converted (as already

              mentioned in my first post), into CMYK by Acrobat Pro, which should concern

              only the Lab colors, not CMYK K-only parts.

              A preview by Softproof in Photoshop (document Lab, Preview ISOCoated-v2(eci)

              for instance, can be used to detect ugly effects of gamut clipping early.

              Where is Color Management involved?

              a) in the monitor appearance of Lab values. This should be identical for in-gamut

              swatches.

              b) in the final conversion of Lab to CMYK. Precisely at only one stage - in Acrobat.

               

              Even if the appearance should not be identical - the Lab values are nowhere changed

              in the workflow. Lab values are never out-of-gamut in Lab space.

               

              Another example: Lab data of the mentioned doc were imported in Photoshop,

              exported in groups as files (probably as *.ase  / Adobe Swatch Exchange, but here

              I'm not sure about) and used in Illustrator for experimental Tracing graphics:

               

              http://www.fho-emden.de/~hoffmann/casamunsell24062012.pdf

               

              Best regards --Gernot Hoffmann

               

              Edited: *.ase

              • 4. Re: LAB Swatches produce different colors in ID, PS & Illy
                MarieMeyer Level 1

                Hello Gernot and Rick. Sorry it has taken me so long to respond - the holidays intevened.

                 

                Rick, I tried your process and got the same result.

                 

                This got me thinking, so I conducted a little experiment: As before, I had ID, PS an Illy sychronised. I opened new documents in each, and used the CMYK sliders to make simple brights: C100 0 0 0 ; C0 M100 0 0, etc. 

                 

                Then I looked up the LAB values that the program displayed for each. They differed from program to program.

                 

                Therefore, I suspect the problem am I seeing is do there being small differences between the way the Adobe Color Engine is implemented in each program. As I understand it, they have completely seperate development teams, so maybe that is not surprising. Also, I am using CS4; perhaps they have been brought into line in new versions.

                 

                Thanks again for your help.

                • 5. Re: LAB Swatches produce different colors in ID, PS & Illy
                  Level 5

                  Ah, the totally artificial suite concept.

                   

                  Inconsistency between or among applications in the artificial "suites" should come as no surprise.

                   

                  The "suite" concept is an invetion of Adobe marketing and bean-counting types.  The engineering teams are totally independent of each other, they are not only in different buildings but in different cities and states of the American Union, even in different countries. 

                   

                  The fact that they have little if any communication among them is highlighted by requests occasionally made in these forums by top Adobe engineers to let the other teams know when there are problems in one application that impact our workflow in another one.