15 Replies Latest reply on Jun 9, 2016 9:20 AM by rob day

    Halftone Photos Stepping when Printed

    altpress Level 1

      We are using a Xerox 700 EX with the Graphic Arts Premium Package and when we print a postscript file from InDesign CS5 with all the lpi settings and angles, then choose to use Application Defined halftone settings in our Fiery RIP to print them, it is taking a nice halftone photo and causing stepping. Looks almost like it is solarized. When we use the GAPPE halftone settings it does not do this, but then it does not rotate the dots for 4 color process printing. I need to know what in InDesign is causing the solarizing/stepping in my photos. Please help. I have changed every setting I can think of in the print settings and nothing changes/fixes it.

        • 1. Re: Halftone Photos Stepping when Printed
          Jeffrey_Smith Most Valuable Participant

          You could take the application (indesign), print driver and postscript out of the equation entirely, and submit PDF to the RIP. Then the onus of screening is on the RIP exclusively.

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          • 2. Re: Halftone Photos Stepping when Printed
            altpress Level 1

            But then I don't have the options for separations. If I submit a separations pdf it defaults to everything being at 45 degree angle for black ink. If I use the progressive function of the EX700 Fiery, it adds the yellow security dots in the background of everything causing artifacts in my screens.

            • 3. Re: Halftone Photos Stepping when Printed
              Jeffrey_Smith Most Valuable Participant

              it adds the yellow security dots in the background of everything causing artifacts in my screens.

              This sounds like a color management issue or a specific setting on the DFE that uses a cluster dot screening for best image results. Do you need conventional dot screening for this project?. IMO the Xerox 700 has better quality using the cluster dot.

              • 4. Re: Halftone Photos Stepping when Printed
                rob day Adobe Community Professional & MVP

                When you print out of InDesign is Graphics>Send Data set to All?

                 

                If I submit a separations pdf it defaults to everything being at 45 degree angle for black ink.

                 

                Just to be clear by submit a separations pdf do you mean you are distilling a separated postscript file, or exporting a composite PDF/X and outputting separations from AcrobatPro? If it's the latter are you saying you can't edit the Angle under Advanced>Output tab when the Color dropdown is set to Separations?

                 

                Screen Shot 2016-05-25 at 2.21.51 PM.png

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                • 5. Re: Halftone Photos Stepping when Printed
                  altpress Level 1

                  We do use the cluster dot function. Xerox copiers have a security feature that prints microscopic yellow dots on everything you print in color so they can track who printed something if legally needed. i.e. fake money. We are using this to do printing plates for our offset presses. So those "extra" yellow dots mess up a four color process once printed. Ink sees those yellow dots and prints on our jobs. But if we print in black ink, separations, those dots are not there.

                   

                  We are taking the .ps file and dropping it directly into the Fiery Command Workstation for processing and printing, then telling it to keep the dpi/lpi/screen angle settings from the Application (InDesign). It is taking a photo that is high resolution and has smooth tones and making stepping/solarizing look to it. Maybe you can see what I mean in the picture below.

                  20160525_141204_resized_1.jpg

                   

                  I have hit every button/setting I can find and nothing gets rid of the solarization. It does it to all photos/halftones.

                  • 6. Re: Halftone Photos Stepping when Printed
                    rob day Adobe Community Professional & MVP

                    Looks like compression artifacts

                    • 7. Re: Halftone Photos Stepping when Printed
                      Danny Whitehead. Level 4

                      altpress wrote:

                       

                      We are using this to do printing plates for our offset presses.

                      How? I've not seen a laser-printer-as-imagesetter workflow since 1992, and that was on black and white press ads and involved a lot of time in the darkroom.

                       

                      Generally, I don't think laser printers reproduce very well when not using  their own, optimised halftone settings.

                      • 8. Re: Halftone Photos Stepping when Printed
                        altpress Level 1

                        What do we do to eliminate the solarization of the pictures??

                         

                        Our Xerox produces near imagesetter quality dots. This is the only hiccup we have encountered, but want to give the best quality our machine is able to do. We have the Graphic Arts Premium Package which is what gives us the ability to control the dots at all. Thank you all for helping. We have been researching and fighting to make this work for a long time and just want to solve what Xerox and Fiery won't or can't. We appreciate any and all suggestions to fix this problem.

                        • 9. Re: Halftone Photos Stepping when Printed
                          Jeffrey_Smith Most Valuable Participant

                          When you are printing postscript, in the print menu > under Graphics tab > Image: Send Data - Is this option set to "All" or "Optimized Subsampling" ?

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                          • 10. Re: Halftone Photos Stepping when Printed
                            altpress Level 1

                            What are compression artifacts?

                            • 11. Re: Halftone Photos Stepping when Printed
                              altpress Level 1

                              We are getting imagesetter quality dots with our Xerox. Just need to figure this one issue out for them to be perfect. They are good enough for 4 color process work.

                              • 12. Re: Halftone Photos Stepping when Printed
                                altpress Level 1

                                Yes, we do have that checked.

                                • 13. Re: Halftone Photos Stepping when Printed
                                  Danny Whitehead. Level 4

                                  Is it only from InDesign where you're seeing this stepping/banding? Can you print to Postscript, specifying custom angles from other apps and have the Xerox honour them with no stepping/banding?

                                   

                                  Because I still suspect that the printer simply isn't capable of 256 grey levels when using custom screen angles.

                                   

                                  What LPI/frequency are you using?

                                  • 14. Re: Halftone Photos Stepping when Printed
                                    Jeffrey_Smith Most Valuable Participant

                                    Artifacts occur during lossy compression methods. Image content is altered to create more contiguous blocks of similar color to allow higher compression, and smaller files, and basically the posterized effect that you see in your sample.

                                     

                                    If you are printing postscript with all image data, you would not see additional compression artifacts. If you export PDF, the compression method chosen can introduce compression artifacts. The original image, most likely a jpeg, may already have compression artifacts in it, and are more noticeable when viewing a color separation.

                                    • 15. Re: Halftone Photos Stepping when Printed
                                      rob day Adobe Community Professional & MVP

                                      What are compression artifacts?

                                       

                                      When an image gets compressed via a lossy format like JPEG you'll see blocky artifacts if the compression is low quality. For CMYK there will be more artifacts in the lighter value channels, which seems to be the case in your yellow separation. Here's the yellow channel of a heavily compressed JPEG and a PSD with no compression:

                                       

                                       

                                      Screen Shot 2016-06-09 at 12.15.02 PM.png