16 Replies Latest reply on Sep 15, 2011 2:54 PM by Peter Spier

    Help: Applying a basic feather to a photo alters appearance

    hoosker

      In a CS4 InDesign document (CMYK transparency blend space) when I apply a basic feather to a greyscale photo the photo becomes noticeably lighter. This washed out effect is very undesirable. When I export a high quality PDF the photos also look muted. I have not noticed this with RGB photos. Does anyone have a suggestion on how to avoid this? I searched the web for an explanation without any luck. This document will be offset printed.

       

      thanks

        • 1. Re: Help: Applying a basic feather to a photo alters appearance
          Peter Spier Most Valuable Participant (Moderator)

          When you add transparency to the page you force ID to use a better preview. Rob Day has explained what happens with grayscale a few times lately, but the gist of what you are seeing is that the grayscale numbers are really being added to the black plate of the CMYK color space specified (ID doesn't support grayscale profiles) and your preview is showing you what those numbers will look like in print. You should see the same effect on a page without transparency if you switch to overprint preview.

           

          When you export, the images are also incorporated into the black channel and displayed according to the CMYK profile.

          • 2. Re: Help: Applying a basic feather to a photo alters appearance
            hoosker Level 1

            Thanks Peter for your reply.

             

            Is there anything I should be doing to make greyscale photos look better for off-set printing? My magazine will be printed black plus one PMS spot color. I will search for Rob Day's information.

            • 3. Re: Help: Applying a basic feather to a photo alters appearance
              Peter Spier Most Valuable Participant (Moderator)

              One possibility is to load the black channel of your target CMYK as your gray profile in Photoshop:

              LoadGray.png

              • 4. Re: Help: Applying a basic feather to a photo alters appearance
                Peter Spier Most Valuable Participant (Moderator)

                That said, I usually use a dot gain 20% profile for grayscale on coated stock, and go for a little lighter than I think it should be (but that's a seat of the pants method based on lots of experinece with my printers).

                 

                The "little lighter," by the way is a general rule. Images always look better run a little too light than a little too dark, so if there's too much ink running because the pressman is asleep you won't get mud, and if there's not quite enough your images will probably still be "OK."

                 

                Had a painter last month who didn't listen to me about this and one of the most important images in his show catalog ended up just a little too dark...

                • 5. Re: Help: Applying a basic feather to a photo alters appearance
                  Marcy McGuire Level 1

                  I seriously wish I understood this. I need to solve this problem with my b/w ads. They look pretty boring without any effects.

                  • 6. Re: Help: Applying a basic feather to a photo alters appearance
                    Marcy McGuire Level 1

                    I really love working in ID. That being said not being able to creatively work with greyscale images is a serious flaw in the software! Although I still don't understand the "fix", I have found a go around. For my particular project I only have 5 b/w pages in an otherwise entirely 4 color magazine. So for this issue I have converted my greyscale images to cmyk, leaving them as b/w. Went back in ID, created drop shadows & bevels without affecting the image quality. Temporarily I have a solution, but this won't work long term.

                    • 7. Re: Help: Applying a basic feather to a photo alters appearance
                      Peter Spier Most Valuable Participant (Moderator)

                      To load the black channel as the gray profile in Photoshop, Edit > Color settings....

                       

                      Press "More Options" button if the advanced options aren't showing, then in the gray profile dropdown choose "Load Gray..."

                       

                      Slect your CMYK target profile, and Photoshop will load the black ink channel.

                       

                       

                      Are your color images coming out OK?

                      • 8. Re: Help: Applying a basic feather to a photo alters appearance
                        Marcy McGuire Level 1

                        I don't have the same issues with the color pages.

                        I have attached a screen shot of my profiles, all I see are monitor calibration profiles.

                        • 9. Re: Help: Applying a basic feather to a photo alters appearance
                          Peter Spier Most Valuable Participant (Moderator)

                          Attachments don't work. Either post a link to an external server or embed a screen shot using the camera icon on the web page:

                          CameraIcon.png

                           

                          Seriously, there are no CMYK profiles on yur system? Check the Adobe common files under Color... Not sure of the path on Mac, probably under Applications or Library.

                          • 10. Re: Help: Applying a basic feather to a photo alters appearance
                            Marcy McGuire Level 1

                            I was looking in the user library, not the HD library. I found it in the HD library and have now loaded the profile.

                             

                            Now to test it out!

                             

                            Thank you for all your help.

                             

                            Marcy McGuire

                            • 11. Re: Help: Applying a basic feather to a photo alters appearance
                              Marcy McGuire Level 1

                              following in Rob's screen shots exactly and realizing I was in the wrong Library worked!

                               

                              Thank you for all your help!

                              • 12. Re: Help: Applying a basic feather to a photo alters appearance
                                hoosker Level 1

                                Just to recap my original issue...

                                 

                                This is a magazine that all pages will be off-set printed in black ink only except for the cover which has a duotone (black and 1 pms saved as eps). But the images in question are photoshop greyscale.

                                 

                                If I understand correctly, InDesign does not preview the grey scale correctly until you add transparency which in this case is a feather. It then is forced to preview the greyscale image as it would look only using the black plate. This in comparison to a cmyk black and white photo which would be printed as rich black using some of the color plates too. So I am seeing a more muted black ink only image.

                                 

                                What is interesting is that when I export a high quality PDF it shows the same phenomena. The greyscale image with the feather looks more muted. Actually all images on the page become muted even if only one has the feather. If I export a high quality PDF with no feather the images are darker.

                                 

                                Then I did the same thing but exported a press quality and all images look more muted whether I used a feather or not. So maybe it is the black plate only vs rich black that I am seeing.

                                • 13. Re: Help: Applying a basic feather to a photo alters appearance
                                  Marcy McGuire Level 1

                                  my understanding of Rich Blacks is they are basically CMYK, so you can't use them on a b/w print job.

                                   

                                  I had exactly the same problems with my magazine, which is mostly 4c but I do have some b/w pages. All my b/w pages were flat.

                                   

                                  If you can find my thread, Rob has a detailed screen shot for changing the photoshop settings. THIS WORKS! However, the photos were WAY to contrasty for my print job. I had to convert them to CMYK then in Levels take the black almost completely out and then convert them to grayscale.

                                   

                                  So bottom line, as I understand it, is ID doesn't work in greyscale, everything has to be CMYK even if it only uses the black channel.

                                   

                                  Marcy McGuire

                                  • 14. Re: Help: Applying a basic feather to a photo alters appearance
                                    Peter Spier Most Valuable Participant (Moderator)

                                    hoosker wrote:

                                    If I understand correctly, InDesign does not preview the grey scale correctly until you add transparency which in this case is a feather. It then is forced to preview the greyscale image as it would look only using the black plate. This in comparison to a cmyk black and white photo which would be printed as rich black using some of the color plates too. So I am seeing a more muted black ink only image.

                                    To get an accurate preview of imported grayscale anytime you can turn on Overprint Preview.

                                     

                                    True grayscale is certainly more muted than an image using a "rich gray" four color mix, but the phenomenon you are seeing with shifting tone and contrast is related to preview and the difference between the grayscale profile representation in Photoshop (where the grayscale profile is supported) and the representation of those numbers in the working cmyk profile black channel in ID, which moves all black ink into that channel. The reason for doing that is that when it's time to make plates you don't have a "gray" plate, only the C, M, Y, K and spot colors, and grayscale is really just screened K.

                                     

                                    It's also very important to set the preferences for Appearance of Black correctly, which they are not (in my opinion) by default, if you are going to print the document. I set to display all blacks accurately, which is not at all controversial and shows on screen the difference between K-only and rich blacks, but I leave output as output all balcks as rich black. This seems counter-intuitive, but the setting only applies to print or export to RGB devices and printing to PDF as composite gray (not exporting, because you can't). If you set output to accurate and send a print job to your monochrome printer or to grayscale PDF (and I don't advocate printing to PDF to get grayscale except under special circumstances -- a properly prepared file with only black ink can be exported to PDF just fine), your 100% K type and other elements will render as a screen with a percentage value someplace in the 90s so that any rich blacks that might be in use can be rendered as dark as possible at 100% K.

                                    • 15. Re: Help: Applying a basic feather to a photo alters appearance
                                      Marcy McGuire Level 1

                                      After several reads, I do understand what you are saying. I must admit some of this is a bit over my head, which brings me to another question.

                                      I export all my ads as PDF files to be placed  on the pages as graphics. If I set it to print all blacks as rich black does this effect the export? Will my greyscale ads essentially be built CMKY?

                                       

                                      Marcy McGuire

                                      • 16. Re: Help: Applying a basic feather to a photo alters appearance
                                        Peter Spier Most Valuable Participant (Moderator)

                                        The rich black preference should not affect an EXPORT to PDF, though you must still choose a composite CMYK output. Your grayscales will be transferred to the K plate only, so unless you have other objects that us C,M, or Y those plates will not be used (except by printers marks if you add them, but there is no need to output those otherwise blank plates at press time).