9 Replies Latest reply on Feb 4, 2013 11:03 AM by rob day

    Use Standard Lab Values?

    phyllisj9 Level 2

      I somtmes use spot colors that I convert to CMYK.  I once read somewhere (maybe here) that results are generally better if you place a checkmark beside "Use Standard Lab Values for Spots."  Is that true?  I'm using Color Bridge Plus colors now -- they're Pantones, but they all have CMYK equivalents.  I don't know if I'll mess up the conversions with that setting or not (?).

       

      Thanks, Phyllis

        • 1. Re: Use Standard Lab Values?
          Rik Ramsay Level 4

          It depends on whether you have a colour managed workflow or not. The LAB values for pantone will give a much better representation on screen but depending on your application colour profiles, could give you different CMYK breakdowns of those pantone colours.

           

          LAB colours are absolute. Your profiles determine the relative RGB and CMYK values.

           

          See: http://help.adobe.com/en_US/InDesign/6.0/WSa285fff53dea4f8617383751001ea8cb3f-7025a.html

          • 2. Re: Use Standard Lab Values?
            Rik Ramsay Level 4

            Just to add to this, I think pantone Bridge reference CMYK colours using the Euro print profile. In that case, as you're based in America (assumed from your "color" spelling) it would be more accurate for you to have the LAB box checked when converting your pantone to CMYK as you're likely running the US_SWOP print profile. If printing in Europe and you're running a Euro profile in InD, you can use the CMYK mentioned in the pantone Bridge guide.

            • 3. Re: Use Standard Lab Values?
              rob day Adobe Community Professional & MVP

              If your document is going out to different printing destinations where in one case the color is actually printed as a spot and in other cases it needs to print as process CMYK, Lab is better because it will get converted to the CMYK profile used at output—better assuming the printer has an acurate profile in place. The Pantone CMYK builds are device specific—their printed appearance would change depending on the press conditions—that wouldn't be a problem if the press conditions are similar to what Pantone expects, but might be a problem for unusual conditions like newsprint.

               

              If you are using the Pantone system as a reference for picking process color, you would be better off using one of the process libraries where the swatches you are referencing are actually printed as CMYK and are all in gamut.

              • 4. Re: Use Standard Lab Values?
                phyllisj9 Level 2

                Thanks everyone. This is very helpful!

                 

                Phyllis

                • 5. Re: Use Standard Lab Values?
                  phyllisj9 Level 2

                  Digging up an old thread of mine as I'm still kind of unsure about this.  If I'm printing only in CMYK, but my magazine contains advertisements in which the originals were spot colors, am I better off checking or unchecking "Use Standard Lab Values"?  Obviously I have to check "all spots to process."

                   

                  Thanks, Phyllis

                  • 6. Re: Use Standard Lab Values?
                    phyllisj9 Level 2

                    P.S.  I guess I'm just trying to figure out a good default position to take on this.

                    • 7. Re: Use Standard Lab Values?
                      rob day Adobe Community Professional & MVP

                      If you are using CS6 and the latest Pantone libraries there's no longer a choice—unchecking Use Lab... has no effect. The conversion of a solid spot color to CMYK is now always a color managed conversion from Lab to the document's CMYK space, which is defined by the assigned CMYK profile.

                      • 8. Re: Use Standard Lab Values?
                        phyllisj9 Level 2

                        Hey, I'm still in CS 5.5 (sigh).  I'm just wondering if it makes any difference -- I'm not going to print anything in spot colors, all in CMYK.  Just wondering whether it's best to check that or leave it unchecked before I make all these PDFs.  I'd ask the printing company, but it'll take them forever to get back to me.  I've probably done it both ways in the past and am not even sure which one was better.  But I'm consciously thinking about it and would like to make the best pick before I start making the printer files.

                         

                        Thanks, Phyllis

                        • 9. Re: Use Standard Lab Values?
                          rob day Adobe Community Professional & MVP

                          I'm not going to print anything in spot colors, all in CMYK.

                           

                          In either case the CMYK color that gets printed is a simulation of the solid ink swatch you are referencing—the solid inks have no relationship to CMYK printing.

                           

                          There could be problems with the accuracy of the simulation with either approach. The CMYK  definitions could be a problem if your printing conditions don't match the conditions Pantone expected when they came up with the simulation values. The Lab definitions might not be accurate if your document's CMYK profile is not correct for the destination press.

                           

                          In general the Lab colors converted to your document's CMYK is the better approach, which is why the CMYK definitions for solid colors are no longer available in CS6.