20 Replies Latest reply on Sep 27, 2011 2:20 PM by rob day

    Setting ink limits when exporting to PDF

    Colin W

      I'm putting together a regular 80 page magazine in ID CS4.

       

      Content is mix of ID-created text and imported images (mostly in jpg or PSD formats) plus adverts which are usually PDFs produced out-of-house

       

      The printer's have requested that I use ISO Coated V2 300%(ECI) colour profile, so I have assigned that as my working space and synchronised all Adobe applications.

       

      When I export to PDF, I use Pass4press V10 settings, with Output set to "Covert to destination (preserve numbers)"  which says that colours will only be converted if they have a different embedded profile, or they are RGB.

       

      When I preflight the resulting PDF, I'm getting loads of over-inking errors (up to 400% in some cases), mainly from the imported PDFs.

       

      Any help on what setting I need to have to make sure that the final output PDF is limited to 300% total inking?

        • 1. Re: Setting ink limits when exporting to PDF
          Peter Spier Most Valuable Participant (Moderator)

          Don't preserve numbers....

           

          This may or may not be an issue for content you get from outside. Any native objects will already be in the correct space, so numbers for those will be preserved and you won't get rich-black conversions on your type, for example, but anything that has an embedded profile will be converted, so you should get the correct ink limits there. The problem will be that any imported PDFs with embedded profiles that are not the same as your working space may have 100% K converted to a 4-color mix, and any that have no embedded profiles will be presumed to be in the working space, so over-limit numbers will be preserved. And even native objects can be created in your space with too much ink -- profiles don't protect you agianst intentional violations fo the ink limits.

           

          Basically, there is no simple solution. The best thing is to publish your specs to your advertisers and get them to give you PDFs that already are inthe correct space and use the correct limits.

          1 person found this helpful
          • 2. Re: Setting ink limits when exporting to PDF
            rob day Adobe Community Professional & MVP

            I'm getting loads of over-inking errors (up to 400% in some cases), mainly from the imported PDFs.

             

            Also, check your Color Setting's CMYK policy.

             

            If it was set to Preserve Numbers (Ignore Linked Profiles) or Off when you created the magazine document then the placed PDF's are assigned your docs CMYK profile and the problem PDF CMYK values will output unchanged. To honor your profile's 300% ink limit you'll have to force a conversion of the placed PDFs—for most press conditions 400% total ink  a bigger problem than 4-color blacks.

             

            If you can't reject the problem ads you'll have to make sure the ads have a conflicting profile (US SWOP? most user's default) and ID's CM policy is set to honor the incoming profiles. See this thread on changing an existing doc's policy:

             

            http://forums.adobe.com/message/3932909#3932909

            • 3. Re: Setting ink limits when exporting to PDF
              Colin JC Williams

              Thanks for the advice.

               

              However, as a good percentage of our advertisers (including some that get their ads done by professional, and quite large, design agencies) can't even get the ads the correct size when given precise measurements, then I fancy that trying to get them to assign a correct colour profile (which we do actually tell them) and without any violations is going to be tricky to say the least.

               

              OK, I know I'm not terribly good at theis colour management lark, but I'm really getting confused here.

               

              I created a new test document in Indesign. Working spaces are Adobe RGB and Iso Coated v2 300%. Policy is set to preserve embedded profiles

               

              If I place an RGB image, tagged with sRGB or Adobe RGB profiles into my document, then export to PDF using Pass4Press v10, ouput set to Convert to profile, and the profile is  Iso Coated v2 300%, I though I should be OK. As the images' profiles should be converted on output to the 300% limit. But when I check with Acrobat's output preview, total coverage 300%, I still get bits of the images showing up as over-limit.

               

              I haven't even started on trying out PDFs yet. I imagine they are going to be even more difficult!

              • 4. Re: Setting ink limits when exporting to PDF
                Peter Spier Most Valuable Participant (Moderator)

                How are you checking the ink limit? One of the annoying things about the ink limit highlights in Adobe products is that they actually highlight the threshold value, too, so if you are OK at 300% and don't want to see that highlighted, set the limit to 301%.

                • 5. Re: Setting ink limits when exporting to PDF
                  rob day Adobe Community Professional & MVP

                  Try exporting without any compression or downsampling. When you resample or compress the pixels get interpolated, which can push 300% pixels over the limit by a percent.

                  • 6. Re: Setting ink limits when exporting to PDF
                    Colin JC Williams Level 1

                    I'm using Acrobat Output Preview to check Ink limits. Simulation Profile set to ISO Coated V2 300%.

                     

                     

                    I've been trying different settings out using a test ID document.

                    The ID doc (profile is ISO Coated V2 300%) contains a placed PDF (which is profiled FOGRA27) and a placed JPG (profile is SWOP Coated), both of which have areas of total ink of more than 300% and an ID-created box set to 0:100:100:0

                     

                    If I export to PDF from ID using Convert to Destination, destination=ISO Coated v2 300%: The result is a few spots of over-inking in the PDF, quite a bit in the JPG (and I mean ink coverage of up to 313%, not just 1 or 2% over). No change to the ID box colour

                     

                    If I export to PDF from ID using Convert to Destination (preserve numbers), destination=ISO Coated v2 300%: The result is exactly the same as the test above.

                     

                    If I export to PDF from ID using Convert to Destination, destination = Japan uncoated 2001 (random, very different, profile just to try an work out what is happening) I get nothing over 300% on either the PDF or the JPG and the ID box changes to 4:91:72:11

                     

                    To be honest. I'm not sure what this proves as yet. I'm still trying to get my head around it.

                    The way I understood it was that the "Convert to Destination" would change any objects in the document that had a different  colour profile attached to them (ie different to the Document's colour space).

                    • 7. Re: Setting ink limits when exporting to PDF
                      rob day Adobe Community Professional & MVP

                      It sounds like the document's CMYK Color Management policy (in Color Settings) was set to Preserve Numbers (Ignore Linked Profiles) or Off when the document was created. If that's the case the JPG's profile is ignored. If you select the JPG on the page and choose  Object>Image Color Settings... what profile is listed?

                       

                      Try making a new document with Preserve Embedded Profiles as the policy and IS0 Coated V2 as the CMYK working space. Place the JPG and export using the PFD/X-4 preset.

                      • 8. Re: Setting ink limits when exporting to PDF
                        Grant H Level 4

                        or let the RIP do it.


                        G

                        • 9. Re: Setting ink limits when exporting to PDF
                          rob day Adobe Community Professional & MVP

                          or let the RIP do it.

                           

                          If the doc policy is Preserve Numbers, the JPG is assigned the document's ISO Coated profile, which is also the destination profile. If the JPG and PDF source is ISO Coated and the destination is also ISO Coated how is the RIP going to make a color managed conversion? If the source and the destination profiles are the same the numbers don't change.

                          • 10. Re: Setting ink limits when exporting to PDF
                            Grant H Level 4

                            well the (lots of) RIP will change the profile (yeah I know!!! before you lash out ) I'm just saying if colin is (unwittingly) going to change the destination profile let the printer or repro house "convert it" correctly.

                             

                            Yes using the profiling software to set rather than within the RIP is better, the same goes for converting an image to cmyk in photoshop and adjusting it to suit the destination rather than letting Indesign convert the images on export. Just time, skill and knowledge inevitably affects the workflow.

                             

                            G

                             

                             



                            • 11. Re: Setting ink limits when exporting to PDF
                              rob day Adobe Community Professional & MVP

                              the same goes for converting an image to cmyk in photoshop and adjusting it to suit the destination rather than letting Indesign convert the images on export

                               

                              There's no difference in a CMYK conversion inside PS and a conversion on export, both use the same color management.

                              • 12. Re: Setting ink limits when exporting to PDF
                                Grant H Level 4

                                the same profile yes but the image quality no way! PS does a way better job. Images are sharper, colour looks better....

                                • 13. Re: Setting ink limits when exporting to PDF
                                  Peter Spier Most Valuable Participant (Moderator)

                                  That depends entirely on if you tweak or sharpen the image after conversion in Photoshop and waht sort of downsampling and compression you apply during export in ID.

                                  • 14. Re: Setting ink limits when exporting to PDF
                                    Grant H Level 4

                                    well, yes and no. downsample a MASSIVE  (4000 x 4000) image in PS (correctly of course) to lets say for final output 50mm x 50mm. Place that file in iD and below it place the massive file in another frame. Export with downsampling above 300 ppi to 300dpi and convert to cmyk: check the difference! and thats just sharpness!

                                    • 15. Re: Setting ink limits when exporting to PDF
                                      rob day Adobe Community Professional & MVP

                                      colour looks better....

                                       

                                      Same profiles and rendering intents will produce virtually identical CMYK values, so if you are getting color that looks better or different you haven't matched up the color settings.

                                       

                                      In this PDF the top swatch file is AdobeRGB, the bottom is the AdobeRGB file converted to CMYK US SWOP. Both ID and PS are sync'd to US Prepress Defaults. The PDF was exported to PDF/X-1a with compression off and the swatch CMYK values match.

                                       

                                      http://www.zenodesign.com/forum/1a.pdf

                                       

                                      Images are sharper

                                       

                                      The conversions are the same pixel for pixel if you are getting softer images it's happening in the downsampling or compression during export.

                                      • 16. Re: Setting ink limits when exporting to PDF
                                        rob day Adobe Community Professional & MVP

                                        Export with downsampling above 300 ppi to 300dpi and convert to cmyk: check the difference!

                                        If there are differences it's caused by the downsampling and compression not the color conversion

                                        • 17. Re: Setting ink limits when exporting to PDF
                                          Peter Spier Most Valuable Participant (Moderator)

                                          Grant H wrote:

                                           

                                          well, yes and no. downsample a MASSIVE  (4000 x 4000) image in PS (correctly of course) to lets say for final output 50mm x 50mm. Place that file in iD and below it place the massive file in another frame. Export with downsampling above 300 ppi to 300dpi and convert to cmyk: check the difference! and thats just sharpness!

                                          This is not a color conversion issue, it's a downsampling algorithm issue. Since we're talking about color conversion, take your down-sampled  (in Photoshop) image and place that, then make a copy in photoshop and do a straight convert to porfile and place that. Now export from ID and conver to the same profile during export. That's a fair comparison, and your colors should be identical.

                                          • 18. Re: Setting ink limits when exporting to PDF
                                            Grant H Level 4

                                            ok: i'm talking about the whole PS vs plain export, my argument iss that you will get better results, converting, tweaking and resizing in PS than you would just placing and exporting.

                                            • 19. Re: Setting ink limits when exporting to PDF
                                              Peter Spier Most Valuable Participant (Moderator)

                                              I would agree with that in general, but it's only true if you are going to take the time and trouble to do that tweaking in Photoshop. Users who just open an image and then go to Image > Mode > CMYK and save the file will see no difference.

                                              • 20. Re: Setting ink limits when exporting to PDF
                                                rob day Adobe Community Professional & MVP

                                                The problem with Photoshop CMYK conversions is they are destination dependent—if you don't know the destination profile then keeping an image in RGB and converting on export is better than a CMYK-to-CMYK conversion on export which is the OP's only option. If the client provided PDF/X-4 with RGB images there would be no ink limit problems or mystery color conversions.