23 Replies Latest reply on Aug 9, 2014 4:00 PM by Ernest Grafe

    "Convert to destination" for B&W ad?

    Ernest Grafe

      Perhaps this is basic 101, but I can't seem to find a definitive answer to this question:  In exporting a PDF from InDesign, does the "Color Conversion" setting in the Output pane affect how a PDF is actually printed on the press?  Or only how it appears on the monitor?

       

      I'm exporting a black-and-white ad for newspapers and magazines.  The ad contains a grayscale photo.  The default output for the "Press Quality" preset includes "Convert to Destination (Preserve Numbers)" with a "Document CMYK" destination.

       

      But that produces a PDF in which the photo appears lighter than the original (as though to compensate for dot gain).  Output Preview in Acrobat shows, of course, that the actual black levels haven't changed.

       

      I've been choosing "No color conversion" instead, so the client sees the ad onscreen as it should actually appear in print.

       

      But is that a mistake?  When the newspaper or magazine imports the ad PDF into their publication, will "No color conversion" cause the photo to print too dark?  Should I, in fact, be using the "Convert to destination" after all?

       

      And it may be that I should be using the PDF/X-1a:2001 preset in this case, but the same question remains: Is Color Conversion needed for a black-and-white PDF?

       

      Thank you very much for your time.

       

      Ernie

        • 1. Re: "Convert to destination" for B&W ad?
          Eugene Tyson Adobe Community Professional & MVP

          Use PDFx4a

           

          It will appear correct on screen and the printers will be able to use this to get the compensation for their newspaper.

          • 2. Re: "Convert to destination" for B&W ad?
            Peter Spier Most Valuable Participant (Moderator)

            ID has no support for grayscale profiles except during export to a grayscale destination. The K values in grayscale images are shown on the K plate (as they should be), and are therefore interpreted as being in the document CMYK space, so in normal view mode they may appear lighter or darker than you see them in Photoshop. Turning on Overprint Preview or Separations Preview should show you an accurate view of how they will print.

             

            Under the scenario you described, where you are converting to profile preserving numbers, the grayscale numbers are not being changed, so you have the same result as if you did no conversion.

            • 3. Re: "Convert to destination" for B&W ad?
              rob day Adobe Community Professional & MVP

              And it may be that I should be using the PDF/X-1a:2001 preset in this case, but the same question remains: Is Color Conversion needed for a black-and-white PDF?

               

              There isn't a way to convert a grayscale image from one grayscale space to another when you export from ID. You can do it in AcrobatPro after exporting.

               

              If you choose No Conversion, Convert to Destination (Preserve Numbers), or Convert to Destination with the destination set as document CMYK; grayscale objects will export unchanged. If you choose Convert to Destination with a CMYK Destination profile that is different than the document CMYK profile your grayscale images will get converted to 4-color CMYK values.

               

              With CS6 or later there is the option to export to a grayscale destination profile, but that still always leaves placed grayscale values unchanged.

              • 4. Re: "Convert to destination" for B&W ad?
                Ernest Grafe Level 1

                Thank you very much to Eugene, Peter and Rob.  I think it's getting clearer.

                 

                EUGENE:  PDFx4a still produces the "washed out" look when I view the PDF in Adobe Reader or Acrobat Pro, but not in Apple's Preview app or on a friend's PC.  So I'm starting to think the "viewing problem" lies in Adobe's profile for looking at PDFs.  (Though I can't find a preference or control for it.)

                 

                What's interesting is that PDFx4a does no "Color Conversion," but then includes "Document CMYK" as the "Output Intent Profile."  That seems to make the difference for non-Adobe PDF viewers.  (In Acrobat Pro's Output Preview pane, the moment I change the "Simulation Profile" to Dot Gain 20%, I get back to the full blacks for both the Press Quality and PDFx4a settings.)  It does seem as if PDFx4a is the way to go.

                 

                PETER and ROB:  It wasn't that I was trying to use grayscale profiles or convert to grayscale.  It was more limited to whether I really need to use "Color Conversion" at all in InDesign's Output panel (for exporting PDFs).  Thank you for confirming that using the "Document CMYK" destination does not affect grayscale images.

                 

                What I take from that is that I could also use the Press Quality setting, modified to "No Color Conversion," and have a PDF that consistently looks good on screen and will print OK as well. (At this point I'm assuming that the various newspapers and magazines use their own methods to compensate for dot gain in imported PDFs.)

                 

                Whoops, I didn't realize I could do only one "Correct answer."  Wanted to give all three.

                • 5. Re: "Convert to destination" for B&W ad?
                  Peter Spier Most Valuable Participant (Moderator)

                  You should assume NOTHING when it comes to newspapers and magazines. Ask them what they want, and if possible get the correct color profiles.

                   

                  The problem with using No Conversion is that any RGB elements will be preserved and those will either be converted in an unpredictable way or the ad will be rejected in preflight.

                  • 6. Re: "Convert to destination" for B&W ad?
                    rob day Adobe Community Professional & MVP

                    (In Acrobat Pro's Output Preview pane, the moment I change the "Simulation Profile" to Dot Gain 20%, I get back to the full blacks for both the Press Quality and PDFx4a settings.)  It does seem as if PDFx4a is the way to go.

                     

                    That's because in Photoshop your grayscales are being previewed via the 20% Dot Gain profile and in InDesign your document's CMYK profile's black ink is being used for the layout preview. So 20% Dot gain is the Photoshop default, but it's not necessarily the correct profile for the magazine version and certainly is not right for newsprint.

                     

                    You can use any CMYK profile as the gray profile in PS. So here I've loaded US SWOP Coated, which is InDesign's default as the Gray working space:

                     

                    Screen Shot 2014-08-06 at 9.48.13 AM.png

                    • 7. Re: "Convert to destination" for B&W ad?
                      Ernest Grafe Level 1

                      I really appreciate your time and effort, Peter and Rob, but there's either some piece I'm missing about "Working Spaces" vs. color management, or something odd about my setup.  Maybe time to go "back to school."

                       

                      Just FYI, Rob, I erred in my remark about 20% dot gain preview.  That works only with the PDF/x-4, which uses "No color conversion" but then adds CMYK as a "Document Profile Intent" under the separate PDF/X heading  And it happens whether I apply the 20% profile in PhotoShop or not (when I click "Don't Color Manage this document' and make sure nothing is checked in Save As).

                       

                      So no matter what I do, the PDF looks grey on screen unless I turn off Color Conversion in the Press Quality setting while exporting.

                       

                      Absolutely agree about the danger of assumptions, Peter, and use any profiles I'm  provided.  But these are mostly small (sometimes student) papers and magazines that just say PDF at 300 dpi.  I've actually been using "No Conversion" for several years without problems, being careful about all the pieces and checking the K plate in Output Preview.  But the ads were redesigned recently (I'm just a production guy), and the designer apparently used the PDF/x-1a setting from Illustrator (according to Preflighting the PDFs).  Thus the client was asking why they looked so grey on screen, worried that would be the way they'd print.

                       

                      Thanks again.

                      • 8. Re: "Convert to destination" for B&W ad?
                        rob day Adobe Community Professional & MVP

                        Thus the client was asking why they looked so grey on screen, worried that would be the way they'd print.

                        In Photoshop the grayscale preview depends on the grayscale profile assignment. The assignment can be one of the generic dot gain curve profiles, or it can be the black ink of a CMYK profile. So here the same output values preveiw differently because top is the default Dot Gain 20% and the bottom is US SWOP Black Ink:

                         

                        gscompare.png

                         

                        inDesign has no grayscale space so it always uses the black ink of the document's CMYK profile. You can't use a gray profile in InDesign, but  you can use a CMYK black ink profile in Photoshop. I think in general a CMYK black ink profile is more accurate because CMYK profiles usually don't define K as absolute black—on press black really prints as dark gray. With newsprint or uncoated papers there's even more loss in black value, and that can be previewed if the correct profile is assigned.

                        • 9. Re: "Convert to destination" for B&W ad?
                          Ernest Grafe Level 1

                          I think I'm following you, Rob, but I'm not finding the "Black Ink - U.S. Web Coated (SWOP) v2" profile you show in the last two posts.  It's not in the popup list for "Convert to Profile" or "Color Settings" in Photoshop.  (I like to use CS 3, but it's not in CS 5 either.)

                           

                          Is it a profile I can download?  One that I need to create?

                           

                          By the way, I came across your recommendation for "Real World Color Management" in another post, and am looking forward to it.

                          • 10. Re: "Convert to destination" for B&W ad?
                            Peter Spier Most Valuable Participant (Moderator)

                            In your Photoshop color settings choose Load Gray from the grayscale dropdown, then choose the CMYK profile you want to use.

                            • 11. Re: "Convert to destination" for B&W ad?
                              rob day Adobe Community Professional & MVP

                              Is it a profile I can download?  One that I need to create?

                               

                              It's also possible to convert from one CMYK black ink to another in Photoshop. So you could maintain the appearance of your current Dot Gain 20% grayscales and change the output numbers.

                               

                              To do that load the CMYK profile as the gray working space as Peter suggests (click More Options if you are not seeing Load Gray), then choose Save Gray and save the black ink profile back to your profiles folder. After saving the black ink profile it should show in your Convert to Profile dialog.

                               

                              Screen Shot 2014-08-07 at 7.26.40 AM.png

                              • 12. Re: "Convert to destination" for B&W ad?
                                Ernest Grafe Level 1

                                It looks like Rob's two-step process (with Peter's help pointing the way) has solved my original issue.  But I have to further reveal my initial ignorance in checking to see if I got it right.  I managed to work a number of years in production without grasping the basic relationships of profiles and workspaces. Everything I read started at some higher level, and I never "got it."  (Not that I do now.)

                                 

                                Here's how I think it's working.  By assigning that 20% profile in Photoshop and then converting to the "Destination Space" of "Black Ink - U.S. Web Coated (SWOP) v2", it appears that I'm in effect amping up the blacks to compensate for the profile that Adobe Acrobat or Reader uses to view a PDF.  Preparing the photo this way is finally giving me a PDF in which the photo looks as it should.  What an enormous relief!

                                 

                                But here's one of the things I'm still not sure of.  That 20% profile for the photo is only to affect the way it appears on screen in the final PDF, right?

                                 

                                Because InDesign's Output setting to export the PDF says "Don't Include Profiles," meaning that whatever I assigned in Photoshop is not getting passed through to the magazine or newspaper that uses the PDF?  Also, InDesign's Color Settings panel uses the SWOP working space, but the Color Management Profile for CMYK is set to "Preserve Numbers (Ignore Linked Profiles)."

                                 

                                So it's actually the Destination setting for exporting PDFs that will control how the PDF is ultimately printed?

                                 

                                I'm really grateful for your hanging in there.  But if I'm still missing the whole point, then I'll just go read the book and stop wasting your time.  Otherwise I have one more question: For the general purpose of ads being sent out to a number of magazines and newspapers, is it generally agreed that the PDF/X-1a standard is the safest?  (Acrobat's Preflight really likes it.)  Or has PDF/X4 become a safe standard?

                                 

                                And in case anyone else wants to go looking for that CMYK profile for "Load gray, I wasn't finding it in the default folder Photoshop was pointing to (in my User's library).  But Peter's post caused me to keep looking, and I finally realized it was in the top level Library > Application Support > Adobe > Color > Profiles > Recommended > "USWebCoatedSWOP.icc".

                                • 13. Re: "Convert to destination" for B&W ad?
                                  Peter Spier Most Valuable Participant (Moderator)

                                  Profiles are a little like dictionaries, if you need a not-very-good analogy.

                                   

                                  Your images use numbers to describe the color, with the numbers representing the density or percentage of coverage of each pixel in each color channel. For Grayscale there's only one set of numbers, the gray level for each pixel. Those numbers don't change, unless you change them, or direct your application or the RIP to change them. The profile contains information that describes how those numbers should look -- the language used and pronunciation, if you will. They provide the context for interpreting what the image numbers mean. The profile tells you if you are looking at Lima, Peru (pronounced Lee-ma), or Lima, Ohio (pronounced Lie-ma).

                                   

                                  If you understand that, it should be obvious that it's important to start out with an embedded profile that describes the image correctly. Assigning the wrong profile can cause a mis-pronunciation, or color shift (or in the case of grayscale, images printing too light or too dark). Depending on your color settings in ID, the program will either preserve the numbers and honor the profile, preserve the numbers and ignore the profile, or change the numbers.

                                   

                                  When you are set to preserve numbers and honor profiles, ID uses the profile information to adjust the image on screen to keep the correct appearance, when set to preserve numbers, but ignore profiles (o when there is no embedded profile), ID presumes everything is in the current working space and displays accordingly (and since there is no inbound support for grayscale profiles, this is how grayscale images are handled -- the numbers are interpreted as being in the K channel of the current working color space). The final option is to have ID read the numbers, then translate to new numbers (change the spelling), so the appearance in the mismatched working space (the pronunciation) is as close as possible to the original intent.

                                   

                                  The same sort of thing happens at output. You can preserve numbers and profiles and leave it all up to the RIP, or you can convert everything to one colorspace and either include a profile or leave the file untagged. If the RIP is set to read them, Tagged files or images will be adjusted in some way to match as closely as possible the output in the tagged space. Untagged files or objects are assumed to be in the correct space and are printed as-is.

                                   

                                  SO, if you've got a grayscale image designed to print on a device with a 20% dot gain and it gets passed through with numbers intact to a device that has 50% dot gain, as you might find on newsprint, everything, in theory, will print way too dark and all of the shadows will block up. I say in theory because newspapers are notorious for inconsistent output, especially small papers and small runs where there isn't enough time and money in the budget to really do much make-ready so ink density is sometimes way off if there is not enough time to adjust it early in the run. I'm production advisor for a student newspaper and we print only 2500 papers, so this is a constant problem for us. My advice to students, and anyone else in a similar situation, is what the editor taught me at my first newspaper job -- to make your images a bit lighter than you think they should be. Most important information is carried in the midtones and shadows, so a light image might survive a bit too much ink on press, and should still be acceptable if the ink is correct or a little thin. In my experience, when the ink levels are off on press it's usually in the direction of too much.

                                  • 14. Re: "Convert to destination" for B&W ad?
                                    Danny Whitehead. Level 4

                                    So it's actually the Destination setting for exporting PDFs that will control how the PDF is ultimately printed?

                                    No, it's the actual press conditions that determine how it prints, and without any knowledge of those, it's a crap shoot. If your Destination Profile (U.S. Web Coated (SWOP) v2?) is embedded in your PDF as the Output Intent (which will happen if you're sending PDF-X and that profile is assigned to your document) the printer may use that as a source from which they will convert to their actual press profile. But more likely, they'll just print the values in you give them, so if you're working with a profile that specifies 15% dot gain for the midtones, but they're actually running at 25% dot gain, your midtones will print 10% darker than expected.

                                    • 15. Re: "Convert to destination" for B&W ad?
                                      rob day Adobe Community Professional & MVP

                                      But here's one of the things I'm still not sure of.  That 20% profile for the photo is only to affect the way it appears on screen in the final PDF, right?

                                       

                                      Yes. Profiles handle color conversions.

                                       

                                      Obviously your display is neither CMYK nor grayscale, so 50% black has to get converted into your monitor's RGB space. Dot Gain 20% is the source profile, the profile assigned to your grayscale document, which describes the expected press conditions. Your system's monitor profile is the destination profile, which describes your monitor (gamma, white point, primary colors). You get the best soft proof if both profiles are accurate.

                                       

                                      If you simply assign a new source profile you get a different softproof, which displays the expected shift in the output values when you print on a coated sheet (i.e., SWOP Coated) vs. newsprint (i.e., SNAP).

                                      • 16. Re: "Convert to destination" for B&W ad?
                                        rob day Adobe Community Professional & MVP

                                        is what the editor taught me at my first newspaper job -- to make your images a bit lighter than you think they should be.

                                         

                                        Prior to Photoshop 7 that would have been your only choice, but now we can make grayscale to grayscale conversions, which will change the output values without changing the display. A conversion from Dot Gain 20% to US Newsprint would be better than an overall lightening because it adjusts for the expected gain in the highlights and midtones, and at the same time compensates for the grayness of the black ink on uncoated in the shadows.

                                         

                                        So the conversion values for DG 20% to SNAP are something like 5%>2%, 50%>44%, and then in the shadows the values get darker 75%>75%, 80%>84%, 95%>98%

                                        • 17. Re: "Convert to destination" for B&W ad?
                                          Peter Spier Most Valuable Participant (Moderator)

                                          While I agree with you in theory, I would still lighten the image a bit in practice, even after using the correct profile, which is calculated for "standard" conditions that don't necessarily exist in the press room, especially in a smaller printer. In my experience, most of us think images are lighter than they really are when we edit (probably due to the difference between transmitted light on our monitors and reflected light in print). I wouldn't go overboard, but a slightly light image is always better, in my book, than one that prints so dark your readers can't make out the details.

                                          • 18. Re: "Convert to destination" for B&W ad?
                                            rsukhram@tgioa.com Level 1

                                            This is a great point.   I design for a real estate agent and she has listing in 3 different newspapers which is a mixture of B&W and color.   I have had all my original images converted to B&W thru lightroom and stored in a separate folder with the same name so I can easily relink to that folder for the B&W versions.  I have had the press in the past tell me that files contained CMY values and this seemed to be the only way to correct that.   I will try the suggested to see if it is a good fit for me.  It would definitely make it easier if I could simply save as a grey scale (K values only) pdf.

                                            • 19. Re: "Convert to destination" for B&W ad?
                                              rob day Adobe Community Professional & MVP

                                              even after using the correct profile

                                               

                                              Have you ever tried US Sheetfed Black rather than the default Dot Gain 20% or US SWOP?

                                               

                                              If you convert Adobe RGB 128|128|128 mid gray to US SWOP Coated Black Ink you get 60%, and 58% to Dot Gain 20%.

                                               

                                              The conversion to US Sheetfed Coated Black is 51%—7-9% less is a significant midtone difference.

                                              • 20. Re: "Convert to destination" for B&W ad?
                                                Ernest Grafe Level 1

                                                This has been a very interesting exercise.  I miss the days when I had definitive guidelines for the newspaper I produced (maximum 90% full black at the time, and maximum total CMYK percentage of 240%), but I actually feel relieved by Danny's remark that printing can be a crapshoot in the absence of printer-supplied settings.  To repeat, I'm producing ads that go to maybe a dozen newspapers and magazines, and I generally don't even see tear sheets.

                                                 

                                                What's more, both the Press Quality and PDF/X-1a Adobe presets specify "Don't Include Profiles," so doesn't that mean that any profile attached to a photo in the ad would not be passed along to the printer?  In Peter's analogy, the original interpretation (numbers) of the photo is/are passed through for the printer to work with in their RIP as they determine they should.  (If I have that wrong, it's the fundamental error under everything else.)

                                                 

                                                In case this is useful to anyone else struggling at my beginner level on profiles, here's a basic experiment I tried.  (Please feel free to point out errors!)  Starting with a photo that had no profile ("Do Not Color Manage This Document"), I filled in three boxes with 30%, 60% and 90% grey.  I then used used "Assign Profile" to add a profile of 20% gray, and saved that.

                                                 

                                                (A quick question about an image being"tagged":  Does the term refer specifically to "Assign Profile"?  And/or checking the "Embed Color Profile" box in the "Save As" panel?)

                                                 

                                                Each version of the image appears identical when imported into the ad in InDesign, no matter the profile assigned in ID.  I assume that's due to the CMYK color management policy in "Color Settings" of "Preserve Numbers (Ignore Linked Profile)."  InDesign is ignoring the profile that was assigned in Photoshop?

                                                 

                                                Each version of the photo also appears identical in the exported PDFs, whether using the the Press Quality, PDF/X-1a or PDF/X-4 presets.  (In the PDFs, the photo appears quite a bit lighter onscreen than the photo itself.)

                                                 

                                                HOWEVER: When I change Acrobat's Simulation Profile to Dot Gain 20% or 30%, the numbers for those boxes do change for the Press Quality and PDF/X-1a settings.  They stay the same for a PDF/X4 export, and for a Press Quality export where I modified the output to "No Color Conversion."  This is true for both the non-color-managed photo and the photo with the embedded 20% dot gain profile.

                                                 

                                                All this leads to what seems like the key issue in terms of the best PDF for the "crap shoot" of printing.  It seems like specifying "No Color Conversion" in the Output panel (as it also is in the PDF/X4 panel) actually does preserve the photo's original numbers.  But the default Press Quality and PDF/X1-a settings allow the numbers to change if different profiles are applied to the PDF.

                                                 

                                                But maybe that's how it should be?  In other words, "No Color Conversion" might constrain the RIP output while "Convert to Destination (Preserve Numbers)" actually allows the printer to adjust for their press?  In other words, does "No Color Conversion" make the printer's job easier or harder?

                                                 

                                                Finally, the thing that did actually alter my photo was the strategy of assigning a 20% profile and then converting to the "Destination Space" of "Black Ink - U.S. Web Coated (SWOP) v2."  The 30% box became 27%, the 60% box became 61% and the 90% box became 95%.  I hope someday to be able to actually understand Rob's sophisticated strategies.

                                                • 21. Re: "Convert to destination" for B&W ad?
                                                  Peter Spier Most Valuable Participant (Moderator)

                                                  Tagged means it has an embedded color profile for other applications to use. The embedding takes place during the save operation if the person doing the saving makes the choice to include the profile.

                                                   

                                                  Acrobat's output preview has changed over the last couple of versions, and not necessarily for the best, so what you see may depend on the version of Acrobat that you are using. And what comes out of the RIP at the printer depends on what the prepress department uses for settings, and the the actual equipment. Can they handle a PDF/X-4 file that has multiple embedded profiles and perhaps RGB? Are they set to honor embedded profiles or output intents? Can they handle live transparency? This is where the crapshoot and guessing game begin when you have no information.

                                                   

                                                  When I send work to my regular printer I send PDF/X-4 because they not only can handle it, they request it, and my prints come back consistently looking the way I expect. When I send ads to newspapers and magazines I try to guess what the print conditions are likely to be, and I send a PDF/X-1a converted to the color profile I hope will be the best match for their press, cross my fingers, say some incantations and hope the ad is readable.

                                                  • 22. Re: "Convert to destination" for B&W ad?
                                                    rob day Adobe Community Professional & MVP

                                                    PDF/X-1a Adobe presets specify "Don't Include Profiles," so doesn't that mean that any profile attached to a photo in the ad would not be passed along to the printer?

                                                    Yes. You only need a profile if there needs to be an additional color conversion downstream. PDF/X-1a assumes you know the final destination and the values in the PDF are correct and should output unchanged—if you have a 50% black object on the page it will output as 50% to the black plate.

                                                     

                                                    Starting with a photo that had no profile ("Do Not Color Manage This Document"),

                                                    Color always gets managed. If you don't assign a profile the Color Settings' current working space is used for conversions and display. In this case Do Not Color Manage means you are choosing not to assign a profile to the document.

                                                     

                                                    Finally, the thing that did actually alter my photo was the strategy of assigning a 20% profile and then converting to the "Destination Space" of "Black Ink - U.S. Web Coated (SWOP)

                                                    Converting (Edit>Convert to Profile) and assigning (Edit>Assign Profile) are distinctly different.

                                                     

                                                    When you convert 2 things happen; the output (plate numbers) are adjusted to compensate for the new destination press conditions, and the new destination profile you converted to is assigned to the image. So with conversions you get adjusted plate numbers and the preview doesn't usually change because of the new profile assignment.

                                                     

                                                    When you assign only one thing happens. The new assignment changes the preview displaying what will happen when you print the same plate values under the new press conditions. So changing the assignment from Dot Gain 20% to Dot Gain 30% darkens the preview showing you what to expect when the unchanged output values print with extra dot gain.

                                                     

                                                    US Sheetfed Coated allows for more dot gain than US SWOP. If you make your conversion to US Sheetfed from Dot Gain 20% you'll see a bigger number change—30>23, 60>53, 90>93

                                                     

                                                    I miss the days when I had definitive guidelines for the newspaper I produced (maximum 90% full black at the time, and maximum total CMYK percentage of 240%)

                                                    All that's handled by the profile when you convert from RGB to CMYK—US Newsprint SNAP has a 220% total ink limit, SWOP's is 300%. You have to make a conversion to get the limits, assigning SNAP to a SWOP image won't limit the ink, you have to convert.

                                                    • 23. Re: "Convert to destination" for B&W ad?
                                                      Ernest Grafe Level 1

                                                      THANK YOU PETER AND ROB!  I feel like I've finally gained some clarity.  I know it takes time from your day to respond, and I'm very grateful.