9 Replies Latest reply on Sep 6, 2011 4:33 AM by rob day

    PDF creation causes rich black colors to shift

    cocteau3 Level 1

      I'm designing a book cover. There are three main areas: front, back and spine. Each area has specified the default "black" color in the swatches panel. This color uses 100% K in the CMYK color space. In the preferences panel, under "appearance of black", I have checked to print and display blacks as rich black. Everthing looks great on the Indesign file. My blacks are as specified. Everything has been double-checked on the swatch panel to be set to this black color, which is a non-editable color (always remains 100% K on the CMYK setting).It has been displaying just fine on the file, as a rich black, no color shifting ever whatsoever until doing the following:

       

      When I make a PDF using the "Export" window, I select PDF/x-1A as my printer specifies. I create the PDF, and open it, only to see that my blacks are being shifted to a shade of deep brownish black.

       

      On the first few attempts, only two of the three areas specified above did this. ON the next attempts, all three areas look the same. This is weird. I'm very disappointed with the strange issues present in Indesign, as I am trained with Quarkxpress and find it to work flawlessly in comparison, especially with something like color output.

       

      What am I doing wrong?

       

      When I change settings, for example, change the color management to "none" or leave it in the default for the PDFx/1-a, it doesn't make any difference in this glitch in the output.

       

      Help!

       

      Thanks.

        • 1. Re: PDF creation causes rich black colors to shift
          Peter Spier Most Valuable Participant (Moderator)

          It sounds like there are two things going on.

           

          First, displaying all blacks as Rich Black is counter-productive. 100%k is not rich black, and it is not as dark as rich black in print, or on screen in your exported PDF, so you are deceiving yourself when you do anything other than display blacks accurately.

           

          Second, if your exported black is going brown it sounds like it has been converted from 100% k to some 4-color mix. This would happen if you export to a differnt profile than your working space and you don't have "preserve numbers" selected.

           

          Do you have Acrobat Pro? If so, waht does output preview say about the black?

          • 2. Re: PDF creation causes rich black colors to shift
            cocteau3 Level 1

            I changed my 100%K only blacks to genuine rich blacks of 100%K 25%C 25%Y 25%M and the problem is co

            rrected. So it seems the indesign "print all blacks as rich blacks" really doesn't work at all...

             

            As for converting colors, I tried many different options and had the same result. But I'm wondering, for

            PDF creation only, what color management settings are optimal? I'm reading over that in my software book...

            • 3. Re: PDF creation causes rich black colors to shift
              TᴀW Adobe Community Professional & MVP

              Dear Cocteau3,

               

              Sometimes it is not the tools that are at fault, but the workman.

              InDesign's "print all blacks as rich blacks" works perfectly, but as far

              as I understand, you are not printing anything. You are creating a PDF

              via the export option. Slight difference.

               

              Thanks,

              Ariel

              • 4. Re: PDF creation causes rich black colors to shift
                cocteau3 Level 1

                To the contrary, as you can see above, it does not work perfectly. Nor does the PDF preclude a color pallette! Especially a PDF x1a...

                • 5. Re: PDF creation causes rich black colors to shift
                  Peter Spier Most Valuable Participant (Moderator)

                  The Appearance of Black setting to print all blacks as rich black ONLY affects printing or exporting to RGB devices (essentially printing to desktop printers or PRINTING to PDF with Composite RGB or Composite Grayscale selected). It has no effect at all on EXPORT to PDF.

                   

                  >I changed my 100%K only blacks to genuine rich blacks of 100%K 25%C 25%Y 25%M  and the problem is corrected.

                   

                  You said this is a book cover. That implies that the output will be printed, not viewed on screen. For printed output it is ESSENTIAL that you set blacks to display accurately. You should also turn on Overprint Preview when judging color. You'll probably get away with your rich black in any type over 12 points or so where it might be applied, but it's generally not a great idea to use rich black for type in small sizes. Rich blacks also generally use slightly more cyan than yellow and magenta to compensate for ink impurities.

                   

                  Do you have a high-end monitor? Is your monitor calibrated and profiled using a colorimeter? If not, you can forget what you see on screen. The odds that it is anywhere near accurate are similar to the odds of winning the lottery. Are you using the same color space in Acrobat as you are in ID? If you change the color space, the appearance of your colors will change.

                   

                  When you export to PDF/X-1a you are converting everything to CMYK using a target color space. By default the conversion option is set to preserve numbers. If your imported art has an embedded profile that differs from the destination, that will be honored and color numbers will be changed to preserve the appearance of color, as much as possible taking into account different gamuts, and untagged imported art, along with native objects will all be presumed to be in the current working space in ID, and cmyk numbers for those objects will be preserved. If the destination space differs from the working space, thew appearance of these colors will shift, but 100% K native objects will continue to be 100% K in the PDF. A conversion to a destination that differs from the working space WITHOUT preserving numbers will result in 100% K being changed to a 4-color mix that mimics the appearance of 100% K output in the working space.

                   

                  Knowing the destination space in advance is vital if you are doing a CMYK conversion. CMYK profiles are "device dependent" and CMYK-to-CMYK conversions are destructive, both in terms of potential loss of color (and you don't gain by going from a smaller to a larger gamut space) and conversion of solid colors to 4-color mixes which is particularly problematic for black type and thin rules.

                  • 6. Re: PDF creation causes rich black colors to shift
                    rob day Adobe Community Professional & MVP
                    When I make a PDF using the "Export" window, I select PDF/x-1A as my printer specifies. I create the PDF, and open it, only to see that my blacks are being shifted to a shade of deep brownish black.... I'm very disappointed with the strange issues present in Indesign, as I am trained with Quarkxpress and find it to work flawlessly in comparison, especially with something like color output.

                     

                     

                    Your document's assigned CMYK profile determines how black is previewed when your preference is set to accurate blacks. If the profile represents the destination printing conditions then a brownish gray might in fact be an accurate preview of 0|0|0|100 black. Most CMYK profiles will preview black with various combinations of CMY differently—reflecting what will likely happen on press. The differences can be significant especially with uncoated sheets. Below are black mixes displayed via SWOP and US Uncoated with Black Point Compensation checked:

                     

                     

                    Screen shot 2011-09-05 at 4.51.34 PM.png

                     

                     

                    Screen shot 2011-09-05 at 4.55.12 PM.png

                     

                    edit: Changed the captures to show with Black Point Compensation

                    • 7. Re: PDF creation causes rich black colors to shift
                      cocteau3 Level 1

                      I seem to have all these setting correct, and my pdfx1-a menus all use "preserve profiles" with CMYK images. My workspace for RGB is Adobe 1998.

                       

                      When I changed to 25/25/25/100 on the black, the problem with the black areas (not text, I'm talking here about large areas of black background on my book cover) went away. The pdf I created looks solid, dense, black, like it should. My differences between before and after look a lot like the examples above in the SWOP coated 2 window. The muddled look changed to solid normal black.

                       

                      I am, however, experiencing a problem when I use the "proof colors" window, with it set to US  WEB SWOP coated v2. It goes back to a muddled, muted black. Not brown, but a less dense, anemic black. I proofed the PDF at Kinko's today on their color laser (obviously not the target output) and got a muddled black. Printing directly from the indesign file yielded a normal black however. I'm posting about this separately.

                       

                      So in summary, my PDF1/xa looks good on screen. I'm using an imac G5. Black and colors look good, photos look realistic and correct. Then, when printing the PDF on a sample color printer, or more importantly, viewing the "proof colors" set to US WEB SWOP coated v2, I get muddled colors.

                       

                      I have all color settings in Indesign as recommended, Adobe RGB 1998 for RGB, US WEB SWOP coated for CMYK, 20% gain, black point compensation, etc.

                       

                      ?

                      • 8. Re: PDF creation causes rich black colors to shift
                        Peter Spier Most Valuable Participant (Moderator)

                        Just to be clear, "solid, normal black" printed as 100% of K ink only is not a particularly dark color. That's why rich blacks are used for large solid areas that should be black. 100% k is going to look pretty washed out next to a rich black.

                         

                        SWOP is a standard that is more or less least common denomnator that can be achieved on virtually any press. It's meant for web-fed presses that run at high speed and the ink limits are very low compared to sheetfed profiles. It's pretty normal for color to look a little blah in SWOP.

                         

                        But that doesn't really address the proffing problems you have. First, as I mentioned previously, you cannot soft proof (proof on screen) unless you have calibrated and profiled your monitor using an instrument. Adjusting color to look good on an uncalibrated monitor is an exercise in futility since what you see bears no realtionship to what the colors are SUPPOSED to look like. If your on-screen proof is inaccurate, where do you put the blame when the colors in a print are differnt?

                         

                        Second, you absolutely need the correct output profile. PDF/X-1a strips the profile inforamtion out of the PDF. If you send that to print, it is presumed that the color numbers are correct for the output space. If you exported to SWOP coated, you must tell your output device to simulate SWOP coated (if it can) when making a digital print. In my experience, operators at places like Kinkos are pretty clueless about color or using advanced features of their equipment, so I wouldn't expect much from a sample produced there.

                        • 9. Re: PDF creation causes rich black colors to shift
                          rob day Adobe Community Professional & MVP
                          Then, when printing the PDF on a sample color printer, or more importantly, viewing the "proof colors" set to US WEB SWOP coated v2, I get muddled colors.

                           

                          Typically you would use Proof Colors to soft proof or view the page as it would print to some other device—a device other than your document's profile destination. So in your case you don't need to turn on Proof Colors to soft proof US Web SWOP because it already is your document's profile.

                           

                          Proof Colors does not allow you to select Use Black Point Compensation or a Rendering Intent both of which have an effect when viewing on screen and separating for an offset press. In most cases you want to leave it checked—uncheck it and you will get the same preview as Proof Colors.

                           

                          US Web SWOP is a profile intended for a web offset press so it's unlikely to be an accurate profile for POD presses. If you are going to set up your document for US SWOP but it's printing to some other device, export it using the PDF/X-4 preset which includes all profiles.