1 2 Previous Next 55 Replies Latest reply on May 23, 2016 8:43 AM by rob day

    Smooth gradients and feathers in PDF/X-1a ?

    Level 1

      Hello folks,

       

      I have learned the hard way I that I should send PDF/X-1a files to my suppliers, so it is what I do. The issue is that Indesign doesn't seem to use any kind of dithering when rasterising solid or transparent gradients.

       

      Is it a missing feature or am I doing something wrong ?

       

      For now, I generate gradients and complex transparency effects in Photoshop and import them in Indesign, but I work with very large files and it has a negative impact on my flexibility for it requires to go back and forth between the two apps (saving and updating large files again and again).

       

      I tried generating a PDF with transparency and flattening it with Acrobat with no luck, but I may be using it wrong ? When I send such a PDF file to my suppliers they either flatten it, introducing image banding (and often using JPEG compression, which further reduces the colour depth, especially in subtle bright gradients), or they try to RIP it right away, which seems to be a rather subjective task because two suppliers won't interpret the same file the same way.

       

      Any ideas ?

      Thanks

        • 1. Re: Smooth gradients and feathers in PDF/X-1a ?
          Eugene Tyson Adobe Community Professional & MVP

          PDFx1a to  your suppliers?

           

          Find new suppliers.

           

          Send PDFx4 files to your new suppliers.

          • 2. Re: Smooth gradients and feathers in PDF/X-1a ?
            c.pfaffenbichler Level 8

            If the printer flattens the transparency the same issues can arise but one may not see them before it’s too late, so I do not quite see how sending a PDF/X-4 would truly solve the issue.

            1 person found this helpful
            • 3. Re: Smooth gradients and feathers in PDF/X-1a ?
              Level 1

              Hi,

               

              I would prefer real-life practical solutions. You don't change suppliers because you are not able to use your software properly. And it's easier said than done.

               

              The "before it's too late" statement is correct. Most of the time you are under crazy deadlines and you don't want to let anything escape your control. I don't want to be behind my suppliers back asking for proofs and asking how they manage my files. It's annoying for them and for me.

              • 4. Re: Smooth gradients and feathers in PDF/X-1a ?
                BobLevine MVP & Adobe Community Professional

                A modern workflow utilizing the Adobe PDF Print Engine does not flatten the transparency.

                 

                PDF/X1-a is archaic. I second Eugene’s recommendation to find a 21st century printer.

                • 5. Re: Smooth gradients and feathers in PDF/X-1a ?
                  c.pfaffenbichler Level 8

                  And from experience you would say that gradients with transparency will not result in banding when the final output happens with Adobe PDF Print Engine?

                  • 6. Re: Smooth gradients and feathers in PDF/X-1a ?
                    BobLevine MVP & Adobe Community Professional

                    I’d say any competent printer given a properly prepared file will provide you with output that is very much predictable. Note the properly prepared part of that. Getting something printed is a partnership that depends on each party to do his/her job.

                     

                    There is an art to preparing gradients and the longer the gradient is the more attention you need to make sure it doesn’t band. You can’t just take two random colors and create and 6” gradient and expect it to be perfect.

                     

                    If it’s a really long gradient, I would actually consider doing it in Photoshop where you can control the rasterization and even add a bit of noise to even out the transition.

                     

                    That said, if you are absolutely stuck with needing to supply a PDF/X-1a you must design accordingly and that means avoiding complicated transparency and effects. There’s a limit to how well these things are going to be flattened and an in many cases it’s the designer’s fault for not taking that into account.

                    • 7. Re: Smooth gradients and feathers in PDF/X-1a ?
                      rob day Adobe Community Professional & MVP

                      introducing image banding (and often using JPEG compression, which further reduces the colour depth, especially in subtle bright gradients),

                      X-1a forces all process color into a single CMYK space, so are you sure the banding is being introduced by the flattening or could it be from an out-of-gamut color conversion?

                       

                      The issue is that Indesign doesn't seem to use any kind of dithering when rasterising solid or transparent gradients.

                      Are you saying the banding only happens when there is transparency involved, or does it also happen with a solid gradient fill?

                      1 person found this helpful
                      • 8. Re: Smooth gradients and feathers in PDF/X-1a ?
                        Randy Hagan Adobe Community Professional

                        While some of the previous respondents may seem unkind, they were looking out for your best interests.

                         

                        If you want to render transparency, you need to be working with vendors who support PDF/X-4, which can handle transparency information in the file. PDF/X-1a is basically a lowest common denominator format for handling CMYK process color reproduction, and utterly useless for rendering transparency. You can find a brief explanation of the PDF/X standards here:

                         

                        PDF/X - Wikipedia, the free encyclopedia

                         

                        In short, if you're running transparency in PDF/X-1a files, you're built to lose. And there are lots of printers who use PDF/X4 standards for that very reason. They're not lying when they say you need to find one of them to get the results you're looking for.

                         

                        If you're concerned about smooth gradients and reducing banding, there are a couple of other factors you need to take a look at:

                         

                        Imagesetter and Platesetter resolution vs. linescreen. Not just the ultimate resolution of the devices, but the settings your printer(s) are using to run your jobs. I work with small and mid-sized printers all the time, and you'd be amazed at the numbers of job shops which have 3600 and 4800 dpi imagesetters that run them at 1200 dpi because the throughput is so much faster at the lower resolution. And there are a lot of job shops which bought used imagesetters from newsprint operations at auction, many of which can't offer higher resolution than 1200 dpi in the first place.

                         

                        At an extreme example, running a 200 lpi halftone on a 1200 dpi, 8-bit imagesetter results in 37 shades between solid black and no image at all. The formula is (dpi/lpi), squared, +1 for no shade at all. Across four channels, that just about guarantees banding. Run that same 200 linescreen job at 2400 dpi, and you get 145 shades between solid and nothing at all. Since the human eye can only pick up between 80-100 shade variations between solid and nothing at all, this gives you lots of room to play with gradients and still get smooth transitions from one end to the other.

                        1 person found this helpful
                        • 9. Re: Smooth gradients and feathers in PDF/X-1a ?
                          Test Screen Name Most Valuable Participant

                          I don't follow the wish for dithering. That's what you do to reduce the colour palette. Classically, when reducing to the 216 colour web safe set. Flattening doesn't reduce the colour palette, dithering doesn't seem relevant. Later on the press we typically have a kind of dithering to halftone dots, but that is out of your control, except to specify halftone parameters your printer may well ignore.

                          • 10. Re: Smooth gradients and feathers in PDF/X-1a ?
                            rob day Adobe Community Professional & MVP

                            dithering doesn't seem relevant.

                            The OP is referring to Photoshop's Gradient dither feature which can minimize banding especially if the blend is long and out-of-gamut. But gradients in ID are not bitmaps (unless they are flattened and rasterized, so dithering isn't an option:

                             

                            dither.png

                            • 11. Re: Smooth gradients and feathers in PDF/X-1a ?
                              BobLevine MVP & Adobe Community Professional

                              I think the point here is that it is imperative that the designer know that gradients need to be created and used properly. There’s nothing magic about it.

                              • 12. Re: Smooth gradients and feathers in PDF/X-1a ?
                                rob day Adobe Community Professional & MVP

                                If you're concerned about smooth gradients and reducing banding, there are a couple of other factors you need to take a look at: Imagesetter and Platesetter resolution vs. linescreen.

                                Yes so I think we have to be careful about assuming the problem is being caused by X-1a's flattening on export and not an output device limitation. Flattening on export can cause problems, but I'm not sure banding is one of them.

                                 

                                If I export a gradient with transparency to the default PDF/X-4 and PDF/X-1a both show the object fill as an Axial blend—I don't see any evidence that there is a change in color bit depth with the X-1a version.

                                 

                                X-1a

                                Screen Shot 2016-05-20 at 9.38.06 AM.png

                                 

                                X-4

                                Screen Shot 2016-05-20 at 9.42.14 AM.png

                                1 person found this helpful
                                • 13. Re: Smooth gradients and feathers in PDF/X-1a ?
                                  rob day Adobe Community Professional & MVP

                                  I think the point here is that it is imperative that the designer know that gradients need to be created and used properly. There’s nothing magic about it.

                                  I agree, but there's an implication in the thread that X-1a is causing the banding. I don't see any evidence that there's a bit depth change with X-4 vs. X-1a.

                                  • 14. Re: Smooth gradients and feathers in PDF/X-1a ?
                                    BobLevine MVP & Adobe Community Professional

                                    Still could be since there was transparency applied to the gradient. That adds to the complexity of the issue.

                                    1 person found this helpful
                                    • 15. Re: Smooth gradients and feathers in PDF/X-1a ?
                                      rob day Adobe Community Professional & MVP

                                      Assuming there are no color conversions, how would you get additional banding without a bit-depth change or a change in the gradient length? You certainly could have a case where the gradient is RGB, and X-4 can leave the gradient unchanged, while X-1a would force a conversion and possibly introduce new or more banding. But that's a color conversion problem.

                                      1 person found this helpful
                                      • 16. Re: Smooth gradients and feathers in PDF/X-1a ?
                                        BobLevine MVP & Adobe Community Professional

                                        Agreed, but that is an X/1-a issue, is it not?

                                        • 17. Re: Smooth gradients and feathers in PDF/X-1a ?
                                          Test Screen Name Most Valuable Participant

                                          Rob Day, thanks for the explanation of the Photoshop dither gradient feature. It sounds an interesting solution to a real problem on certain devices.

                                           

                                          I can confirm that a gradient in PDF is not stored as either raster or vector information, but as a special "gradient" object. There are many kinds of gradient object, but they are defined mathematically for the most part. The simplest is to give end positions and two colours; the output device does the rest. There are gradients for axial filling, and all sorts of more complicated schemes. I can also confirm that these gradients are legal in PDF/X-1a, so they need not be touched. Two exceptions

                                           

                                          * if the gradient has RGB colours, the colours will need to be converted to CMYK. But that won't introduce any more banding than is implicit in the output device.

                                           

                                          * if the gradient is part of a transparency effect, it must be rendered (to raster or vector, probably raster) and blended. At this point banding COULD be introduced. I'd expect most implementations to use 8-bit per channel CMYK raster.

                                           

                                          In transparency blending, there would be the possibility of Photoshop-like blending. But Adobe aren't likely to do any work to enhance an antedeluvian workflow with flattening or PDF/X-1a. It might find itself into Adobe's RIP technology, if it hasn't already. But there's a problem here: a printer investing in a premium RIP is very hard to distinguish from a printer using 20 year old creaking RIPs, until the results disappoint and blame starts flying. After a while, the blame dies down, and things go back to normal; the printer without an investment in better technology can continue to undercut and win bids.

                                          1 person found this helpful
                                          • 18. Re: Smooth gradients and feathers in PDF/X-1a ?
                                            Level 1

                                            Hi again,

                                             

                                            Thank you for the interest you show fo this question.

                                             

                                            I am on a deadline so I can't test things out right now but I find rob day's input interesting : I never use solid gradients with no transparency involved. There is always at least a PSD with some transparency on top of it, so Indesign must merge the two and I wonder how the shading operations are done in this case. I take it Indesign doesn't use Postscript3-like smooth shading, which would explain why it looks so crappy.

                                             

                                            I would like to add that the banding is visible when viewing the PDF/X-1a in Acrobat (when the default [High Quality Print] preset would look good), so it's not an output device limitation issue (although there is some loss when printing depending on the supplier, which only makes the problem more visible).

                                             

                                            Before blaming the supplier or the graphic designer, I think it would be fair to acknowledge that there is an issue with the software : you can't say that the printer should have an up to date raster image processor while, obviously, Indesign doesn't rasterise PDF/X-1a properly. I agree that printers should have up to date RIPs, but their location and the machines they have are far more critical factors for me. If flattening is an issue that can be solved on my end, I would be happy to do it.

                                             

                                            Just to make things clear : I work entirely in a ISO Coated v2 environment. All of my images are tagged with this profile, my documents use this profile and I do no conversion when exporting my PDFs. In Photoshop, my artwork is most of the time embedded in a smart object, which is a 16 bits per channel AdobeRGB document. The main document is a CMYK 8 bits per channel document and doesn't involve transparency merges other than simple alpha cut outs with alpha channels.

                                             

                                            I am well aware of colour management and colour depth issues, and I am very careful when I use gradients and blurs in Photoshop. Moreover, I work with printers on a daily basis, I sign my sheets at the back of the machines and take responsibility for them, I talk to the pre-press guys... I know there are lots of graphic designers who only do web design and work with small RGB files, where banding isn't an issue, and don't know **** about printing, but I am not one of them.

                                             

                                            Test screen name, dithering is often used when working with a reduced colour palette *because* it helps with making those images look better. Gradients are all about colour depth because you have only so many shades to spread on a big area.

                                             

                                             

                                            *post edited mainly to correct grammar / spelling / typing mistakes

                                            • 19. Re: Smooth gradients and feathers in PDF/X-1a ?
                                              c.pfaffenbichler Level 8
                                              Assuming there are no color conversions, how would you get additional banding without a bit-depth change or a change in the gradient length?

                                              When a color gradient and a transparency gradient interact, when two gradients are superimposed with Transparency, … seem possibilities for quantification effects to happen.

                                               

                                              Edit:

                                              X-4 can leave the gradient unchanged

                                              If RGB or Lab elements are present (transparency or not) they still have to get separated at some point when CMYK print is the final product; and if they transparently overlap other profiled content or CMYK images quantification seems a possibility.

                                              • 20. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                rob day Adobe Community Professional & MVP

                                                Agreed, but that is an X/1-a issue, is it not?

                                                You can avoid color conversions on export via X-4, but that just delays the conversion to the output end. Sounds like the OP is working in device CMYK, so there shouldn't be any conversions with either X-4 or X-1a.

                                                • 21. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                  rob day Adobe Community Professional & MVP

                                                  If RGB or Lab elements are present (transparency or not) they still have to get separated at some point when CMYK print is the final product;

                                                  Right that's my point, if the banding is happening because of a color conversion (sounds like it's not), it will eventually happen with either X-4 or X-1a

                                                  • 22. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                    rob day Adobe Community Professional & MVP

                                                    Just to make things clear : I work entirely in a ISO Coated V2 environment. All of my images are tagged with this profile, my documents use this profile and I do no conversion when exporting my PDFs. In Photoshop my artwork is most of the time embedded in a smart object, which is a 16 bits per channel AdobeRGB document. The main document is a 8 bits per channel and doesn't involve transparency merges other than simple alpha cut outs with alpha channels.

                                                    I think everyone was assuming there is transparency in play.

                                                     

                                                    If you are working with device CMYK and the pages don't include transparency, the only difference between X-1a and X-4 is your placed RGB images will get converted to ISO Coated V2 during the export and if you place ISO Coated V2 images there would be no difference. Both X-1a and X-4 export native InDesign CMYK process colors as Device CMYK (no profile).

                                                     

                                                    Placing 16-bit images has no output affect. InDesign has no support for 16-bit color and everything gets exported as 8-bit, which you can see in Acrobat's Object Inspector.

                                                     

                                                    As Randy points out you would have to look at the output device capabilities—a 1200 dpi device atempting to output a 200 line screen would be a problem.

                                                    • 23. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                      Randy Hagan Adobe Community Professional

                                                      To the Original Poster:

                                                       

                                                      To be fair, it really doesn't matter what format the gradient is created in with regards to Vector/Pixel/"special object" because ultimately, the end result is rendered as a raster image. This the the industry's dirty little secret. That's what a RIP (Raster Image Processor) is all about: translating graphic information into output dots/halftone spots to create output, whether to RC paper, film or printing plate. And that's why output resolution/linescreen and bit depth have a direct impact on the end result.

                                                       

                                                      I don't think responders are so much blaming the graphic designer/vendor-printer so much as they're blaming the output device(s) they may use. And while some of the responses may seem damning because they've been branded with "well, the designers should know what they're doing," it's kind of unfair when folks aren't telling you what you can do to get better results with gradients.

                                                       

                                                      So far, the responses have centered around "find printers with better equipment." That's entirely valid, because it gives the output process (and in this case, specifically the processing device) the responsibility to cure a lot of ills. Quality equipment can do that. But there are things that designers can do to cover for shortcomings down the line:

                                                       

                                                      1) Cover less area with gradient effects. In length/width/real estate terms, use less space to render the gradient transition. As a designer, you can do that by using a solid color build on the deep end and overlap it with a gradient "tail" that applies the gradient effect over, say, an inch and a half rather than a two-page magazine spread. With less distance to cover the gradient spread, there's less space for noticeable color banding to occur.

                                                       

                                                      2) Cover more colorspace in gradient blends. In color range terms, use more variation between color builds from one end of a gradient to the other. Going back to the extreme example above, If I build a gradient for an 8-bit, 1200 dpi imagesetter on a 200 linescreen, 10 inches long, with color percentages going from 80C/75Y to 65C/15Y, it'll be easy to see the 4-5 steps in the Cyan color build from 80% to 65%, but the 20+ steps in the Yellow color build between 75% to 15% will be far less evident.

                                                       

                                                      So distance in real estate and colorspace terms have a direct impact on the quality of your gradient. Which is why you're seeing better results with 16-bit Photoshop images, which can render 65,536 distinct shades between solid and no color, as opposed to the 8-bit gradients you get from InDesign, which can only render 256. Even at a 200 linescreen, you can render a lot more steps to smooth the gradient. Which is nice for what you see on the screen, but far more limited for what you can print on an 8-bit output device. It's also why your work is complex and slow because the gradient files you're rendering are freakin' huge. Just scaling back your Photoshop elements to 12-bit rendering will still get you better results and make your files exponentially smaller. Trust me on this.

                                                       

                                                      It's also why working with vendors who have more sophisticated equipment, and more recent standards designed to accommodate the work you're doing will get you much better results. Higher-resolution (2400/3600/4800 dpi output, which is easier to find) and higher bit-rate (12 bit devices - which are relatively rare but are out there) output will get you better results -- whether you create your gradients in InDesign or Photoshop. Let the equipment take up the slack.

                                                       

                                                      And as I and others have previously said, if you're working with transparency, you and your vendors want to be using PDF/X4 standards to get the results you're looking for. It's not InDesign's fault you and your vendors are not getting the transparency effects you're looking for if you're flattening gradients and transparency effects by saving X1-a files which can't render them.

                                                      1 person found this helpful
                                                      • 24. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                        Level 1

                                                        Ok, I thought I was making things clear but I just confused you. There are no RGB images in my Indesign documents, I was referring to my Photoshop documents which are a 8 bits CMYK shell containing a 16 bits RGB document.

                                                        • 25. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                          rob day Adobe Community Professional & MVP

                                                          There are no RGB images in my Indesign documents, I was referring to my Photoshop documents which are a 8 bits CMYK shell containing a 16 bits RGB document.

                                                          In that case PDF/X-4 and PDF/X-1a produce the same results–all of the color would be DeviceCMYK and there's nothing to flatten.

                                                           

                                                          Here's an example of what can happen at the output end. These are scans of printed target press proofs from two different printers. In both cases the output files are the same—the color ramps are deviceCMYK from Photoshop. The top is from a inexpensive online printer, the bottom is from a highend asian printer . The online printer has forced a color conversion even though I sent device CMYK (the black only ramp has CMY) and there is severe banding throughout. The highend proof is nearly perfect.

                                                           

                                                          Vista.jpg

                                                           

                                                          Jade.jpg

                                                          1 person found this helpful
                                                          • 26. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                            Level 1

                                                            Randy,

                                                             

                                                            How do you setup Photoshop to be in 12 bits ? I only get the choice to create 8 bits or 16 bits documents. I would be very interested in doing it to reduce file size and rendering time when I apply filters.

                                                             

                                                            I would be perfectly happy if Indesign gave me a 8 bits flat image (apart from the outlines of course) with moderate banding. Illustrator can do it : I sometimes create rather complex illustrations involving gradients, gradient meshes, blending modes and bitmap effects in RGB (blending modes behave differently in CMYK, it's hard to control), and export in a bitmap format or import in Photoshop and it works like a charm.

                                                             

                                                            Look at this image for example. It's the background of a 1 meter tall poster and it prints OK.

                                                            example.jpg

                                                            detail.jpg

                                                            It's amazing what you can throw at it. There are so many blending operations in this illustration, and you are telling me that Indesign is different and that one or two little gradient feathers is too much ?

                                                             

                                                            -

                                                            Rob, I can only agree with you. I know some printers convert your stuff without even telling you. If I work in ISO Coated v2 it's because most of my suppliers do, and when they encountered FOGRA39 files, they would feed them in a "sanitiser" that would do a lot of crap with my files. I understand your advice as to what suppliers I should work with, but as a graphc designer I should provide my clients with files they can send to anyone and print well. It is contractual. If the supplier changes the file, he has to send a proof for approval (and of course your are buzy and on a deadline and even if you had the time you wouldn't spot the little artefact here or there on a low res JPEG or on a glossy Epson that smooths imperfections out).

                                                             

                                                            It's slightly out of topic but some machines mess with your file without notice too. Recently, I talked to the pre-press guy at my digital printer, he was writing a letter to the manufacturer because when fed with a shade of black, the machine was producing a CMY composition (which wasn't neutral, he would have never noticed otherwise). Some machines have "optimisation algorithms" that are supposed to save ink or allow them to print faster... or make you buy more ink apparently.

                                                            • 27. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                              rob day Adobe Community Professional & MVP

                                                              as a graphc designer I should provide my clients with files they can send to anyone and print well. It is contractual.

                                                              If that's the case an RGB/PDF/X-4 workflow is way more flexible. There is zero advantage in a CMYK PDF that has to be converted into another CMYK space and a lot that can go wrong. If it's not clear what the final destination CMYK space is, leaving the color as AdobeRGB and letting the conversion happen directly into the correct CMYK space at output is more flexible and accurate.

                                                              • 28. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                BobLevine MVP & Adobe Community Professional

                                                                That's some contract. If you gave me those terms, I'd turn the job down.

                                                                • 29. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                  Level 1

                                                                  Rob day,

                                                                   

                                                                  When is the RGB to CMYK conversion supposed to occur in your RGB PDF/X-4 workflow ? Typically, the illustration shown above would not convert well in CMYK before transparency has been flattened or the image rasterised because blending modes are not calculated the same way in CMYK, so I take it it is done very late in the process ? My suppliers (the ones I asked at least) use software like Enfocus Pitstop Pro or Callas PDFToolbox, which work before rasterisation.

                                                                   

                                                                  I have never tried sending an RGB file to an offset / web printer. I expect he would be embarrassed and would try to explain to me tactfully that he needs to engrave CMYK plates before asking me if he can talk to my work placement supervisor

                                                                   

                                                                  Moreover, sometimes you want to control the colour components. For example if I want to darken yellow I will prefer to add magenta over black (or use both) because black makes yellow turn greenish. Or I can try to minimize the risk of out of register texts/strokes by changing their value so there are less components, or maybe I want the print to be laminated and I know that lamination often gives a red shift to the image that the printer will probably try to correct while printing (and sadly no, printers don't create profiles for all of their machines with all possible papers and all possible finish, it's technically impossible), so if I have grays in my artwork I will make sure they don't have many CMY components so they stay neutral even if someone messes with the print... I'm not sure an algorithm will do this kind of stuff always the way I want.

                                                                   

                                                                  I think working in CMYK is a requirement when you intend to print. You can create images in RGB but at some point you need to convert and anticipate printing.

                                                                   

                                                                  -

                                                                   

                                                                  BobLevine,

                                                                   

                                                                  You said yourself that if the file was prepared correctly, the result would be predictable. It's what any client would expect. I most of the time work with my suppliers, but very often my clients have their own suppliers, and if the file is not like they want (and you can take any two printers, they will not ask you the same thing), they will charge them an extra or ask me to send another PDF. Some accept transparency, some don't, some want cut outlines to be placed in the document as an overprint spot colour, others want a black outline in another layer and don't accept spot colours (you would expect that from a digital printer for example), so I send a black outline in a separate file and I send a PDF/X-1a because they are a common denominator.

                                                                   

                                                                  Sometimes you create something in June and it's printed in December, the client expects the file to be accepted by its supplier and doesn't want to have to ask you something at the last minute (when you could be busy) months after the work has been done and the bill has been paid, probably because if you charged them something it would overshoot the budget that had been funded for this project.

                                                                  • 30. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                    BobLevine MVP & Adobe Community Professional

                                                                    adobe01a65700054 wrote:

                                                                     

                                                                     

                                                                    Sometimes you create something in June and it's printed in December, the client expects the file to be accepted by its supplier and doesn't want to have to ask you something at the last minute

                                                                    All the more reason to stick with a format that is adaptable.

                                                                    • 31. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                      rob day Adobe Community Professional & MVP

                                                                      so I take it it is done very late in the process ? I expect he would be embarrassed and would try to explain to me tactfully

                                                                      Yes. The same conversion to CMYK can happen in PS, on export, or at output. Color management is consistent throughout Adobe's print applications, so assuming the destination profile, black point compensation, and rendering intents are the same, it doesn't matter where you make the conversion—you will get the same output values with a conversion in PS, or at export, or at output. In fact Adobe now recommends a placed RGB image>PDF/X-4 workflow which keeps transparency live, and doesn't risk the RGB>CMYK(1)>CMYK(2) conversions you are describing, which could easily produce artifacts and contaminate primary colors.

                                                                       

                                                                      Moreover, sometimes you want to control the colour components. For example if I want to darken yellow I will prefer to add magenta over black (or use both) because black makes yellow turn greenish.

                                                                      That may be, but if your printer forces a CMYK>CMYK conversion all of that subtly will be lost—50% black will be converted to a 4-color mix etc.

                                                                       

                                                                      Both PDF/X-1a and PDF/X-4 protect native InDesign color builds—they export as deviceCMYK with no profile. So you can have a PDF/X-4 workflow where placed images are left as AdobeRGB to be converted at export (if your printer insists on all CMYK) or output to the correct press profile, and InDesign CMYK builds (50%K, 100%cyan, gradients etc.) are left unchanged. But that still doesn't stop a forced intervention, so you would have to communicate that you expect the InDesign builds to output unchanged.

                                                                       

                                                                      I don't think anyone can say for sure what's causing your banding problems because you are not controlling the output process, but you should check the press sheets for evidence of CMYK>CMYK conversions.

                                                                      • 32. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                        Randy Hagan Adobe Community Professional

                                                                        My apologies. I thought you were acquiring image information into Photoshop, not generating it per se. Creating art in Photoshop is in either an 8-bit or 16-bit model. Though I'm curious about your "8-bit container" mention: by my experience, if you're bringing 16-bit art into an 8-bit image in Photoshop, whether acquired or generated, you're going to end up with an 8-bit image.

                                                                         

                                                                        Also, it's not so much that InDesign has a problem rendering narrow color spreads in a gradient; it's that lower-resolution output devices have problems rendering them -- especially across a large area at high linescreen settings. So in the extreme example above, the issue comes from using a 1200 dpi output device and a crazy-fine 200 linescreen over a large printed area. I used that example not only to show extreme worst-case scenarios, but because the math made it easy to illustrate. If you made the same mistake with Photoshop, under the same conditions, dithering might soften it a bit but you'd still end up with the same problem. Let me emphasize this: in this instance, it's not the software's fault; it's in how you adapt it to your preferred set of vendors, and have to take extra effort to accommodate them.

                                                                         

                                                                        As for why are there differences between how Photoshop, Illustrator and InDesign render gradients and transparency effects, it's because, as previous posters mentioned, each program uses a different format to save those elements. Going back to that Dirty Little Secret I offered earlier, that ultimately all prepress files get rendered as raster output before applying ink on substrates, I'd suggest that the best thing you can do is keep using your Photoshop-to-InDesign workflow to get the effect you want through honkin-complex PSD files, then placing them within InDesign and laying basic type and simple design elements over the top. It's probably the best course of action if you're going to stick to a straight-to-CMYK printer workflow.

                                                                         

                                                                        By the way -- really nice work in your example. the analogy I use for your work is the hot-rodding trend to apply "live flames", which involves a lot of airbrushing and translucent effects beyond the traditional "hot rod flames" caricature representations of the '50s and the '60s. It takes a lot of work and demanding standards to pull such things off, but if you can get your client to pay for it, that work should pay off handsomely.

                                                                         

                                                                        If you'll allow me, I'd like to talk about some of the other comments in this thread:

                                                                         

                                                                        RGB vs. CMYK -- Lots of folks look at this call as an either/or, but it's really more about the vendors you work with. Since I'm certified Old School (or some say, certifiable), and I work with a lot of clients who are small-printer job shops, I do a lot of CMYK-intent production work for my in-house collaterals. First, because I support these printers on prepress issues. You do business with the people who do business with you. I work within their capabilities -- and limitations. Second, like a mentor taught me long ago, doing CMYK conversion yourself brings the disappointment of color separation right up front in the process, where you can deal with it. For those printers, I wouldn't have it any other way. I wouldn't dream of handing them RGB art, because it'd come off press with soggy, 400% total ink percentages where they ran the same full-range halftones on every color plate.

                                                                         

                                                                        Hell, for some of 'em, I still generate spot-color jobs. How many folks are doing that anymore?

                                                                         

                                                                        But for other jobs, primarily for production clients with color-managed workflows, I produce pure Adobe RGB output for them to run through their in-house prepress conversion or in-RIP CMYK workflows. I'd never give 'em CMYK art because at the very least it'd choke their throughput and they'd threaten to beat me to a pulp, or at worst taking my color settings, then applying their color settings, and ending up a total mess. This is what Rob Day is referring to about the miseries of CMYK>CMYK workflows.

                                                                         

                                                                        For my multi-channel work, I use a hybrid of RGB for continuous-tone and web-safe colors for solid color builds, then when it's repurposed for print, target it for the printer's intake requirements. That's the best way to ensure I get the results I expect from them.

                                                                         

                                                                        In short, while there might be one way to produce work for one specific production workflow, there's no one way to produce work for any workflow. If you're defining absolute options for how jobs should go, hopefully it's for a limited subset of vendors. Or you're built to lose.

                                                                         

                                                                        To the original poster, the settings you define might eventually work for the subset of vendors you work with, but you're taking a lot of work onto yourself that may be only necessary because of the vendors you're working with. And it probably isn't billable for you. You ought to consider making life easier on yourself by expanding your circle of vendors and exploring what color-managed workflows can do for you. For the folks who are recommending the original poster chuck a current vendor base for a new one using different workflows, that may not be possible for any number of reasons outside of how easy or hard it is to render transparency. It's kinda presumptuous to expect that.

                                                                         

                                                                        And a last suggestion for the original poster: you're really taking a lot on yourself -- that's completely outside your control -- by contractually obligating yourself to jobs which will work with any printer. You're literally giving a printer who screws up a job license to blame it on you, and use their mistake to damage your reputation and take money out of your pocket. Even if it's not your fault. At the very least, you'll be spending non-billable time in a, uh, spitting match between a client's printer and yourself, in front of a client, with hard feelings all around if you win the conflict. At the worst, you'll be giving money and goodwill away for problems that may not even be your fault.

                                                                         

                                                                        I do jobs on contract too, so I know what it's worth to clearly spell out terms when you're working with an outside party. You didn't mention who sets the terms for your job to work with any printer. But if it's you, you really should delete that clause and take it out of your sales pitch. If it's your client(s), you should explain how hard it is to enforce and deliver on such terms, and negotiate your way out of them.

                                                                        • 33. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                          rob day Adobe Community Professional & MVP

                                                                          Second, like a mentor taught me long ago, doing CMYK conversion yourself brings the disappointment of color separation right up front in the process, where you can deal with it.

                                                                           

                                                                          You don't have to actually make a conversion to CMYK in order to see the affect of the conversion to any destination CMYK profile on screen, or check output numbers. If you set the Photoshop Color Settings' Working CMYK space to the destination profile, set Proof Setup to Working CMYK, and turn on Proof Colors, you'll see the conversion into the working space gamut without making the conversion. The Info panel will then show the output numbers for that profile when you set the eydropper to either CMYK or Proof Color.

                                                                           

                                                                          I wouldn't dream of handing them RGB art, because it'd come off press with soggy, 400% total ink percentages where they ran the same full-range halftones on every color plate.

                                                                          If you are printing RGB color out of an Adobe app the CMYK total ink will be set by the destination profile. So out of Acrobat you can choose to let Acrobat handle the conversion or the RIP. If you were to choose ISO Coated v2 as the destination, the maximum total ink will be 300% and the output values would be the same as what you would get out of Photoshop. This works as expected on both of my fairly old RIP driven printers.

                                                                          • 34. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                            Level 1

                                                                            Honestly, even though there seem to be no solution to the problem originally exposed, I don't regret having asked. I have read a lot of quality answers here and I know I will have to do my homeworks because some very valid points have been made, and I'm so used to X-1a I don't know what is legal in other PDF specs and what good they can do to me.

                                                                            Randy Hagan a écrit:

                                                                             

                                                                            I'm curious about your "8-bit container" mention: by my experience, if you're bringing 16-bit art into an 8-bit image in Photoshop, whether acquired or generated, you're going to end up with an 8-bit image.

                                                                            You are right. I think 8 bits CMYK images are OK most of the time, even though I do need to add some noise to even banding out sometimes. There is no point in saving in 16 bits CMYK, It would be way too heavy on my machine and I don't expect printers to take any advantage of it.

                                                                             

                                                                            The idea is to work in 16 bits RGB. If you use a lot of blur filters, gradients, and adjustment layers, you can get a comb toothed histogram very fast, so an 8 bits document wouldn't truly be 8 bits deep (and if you convert to CMYK later on, you only make things worse). My 16 bits documents are not true 16 bits either because I brutalise them a lot, but that's OK, I only need them to be at least 8 bits.

                                                                             

                                                                            Now that you can link smart objects in Photoshop it's easy to work with RGB files in Indesign and swtich to the CMYK versions where you're done (I wrote a little script that toggles between the two based on the file names).

                                                                             

                                                                            I honestly don't know if the container part is necessary but I have had issues in the past with images using a different colour space than the main document. I could see faint rectangles where effects such as drop shadows were applied on Indesign elements. I guess some rounding can happen on the values when you merge a CMYK element with an RGB (or another CMYK colour space) element because you first have to do a conversion. This is why all of my images use the same destination profile as my main document. I find it safer.

                                                                             

                                                                            Switching to full RGB would probably be great, but it's a huge step for me. I mean, at least I need to be able to use overprint 100% K on black texts ! How can I achieve that in an RGB document ? Or can I use a CMYK document and avoid the issue previously mentioned ? I am also worried that, when the file is sent by the client to a supplier I don't know, he is not informed that it is normal that the document contains RGB images (or worse : RGB blending modes) and that he should convert at output or do anything that is unusual for him. My clients are certainly not able to explain or even understand this kind of thing.

                                                                             

                                                                            Would there be a way to make Indesign output a PDF/X-4 and then flatten and convert it to CMYK properly if a supplier asks for this format ? I need to archive my jobs after a while because I work with big files and my SSD has a limited space. Unarchiving stuff and regenerating a PDF is annoying and could even be dangerous because sometimes the document is complex and you can forget to check some things when the client asks you to provide the file quickly because they waited the last minute to send your work to their printer and  they are on a deadline. Typically, if there are conditional texts or layers that should be hidden... it's very error prone to reopen an Indesign document just to export a PDF.

                                                                             

                                                                            Honestly, when I consider it, not using X-1a sounds like an overhead.

                                                                             

                                                                            Randy Hagan a écrit:

                                                                             

                                                                            Also, it's not so much that InDesign has a problem rendering narrow color spreads in a gradient; it's that lower-resolution output devices have problems rendering them

                                                                            Really, it's too bad I can't find a real life example because I have stopped managing transparency in Indesign for some time now but it's really a thing you see in Acrobat, on the screen. There are far less than 256 values in those gradients, and they don't spread that far. Sometimes it happens on something as small as the reflection of a packshot on the floor (which is very fast to do with a gradient feather in Indesign), it's really ugly, but faint (you don't necessarily see it on a proof) and reviled in the final print. When I first noticed it I asked the printer "How come this gradient is broken ? what did you do ?" and they replied "It's not us, your file is like that !", and yes, the crappy gradient was on the file.

                                                                             

                                                                            Randy Hagan a écrit:

                                                                             

                                                                             

                                                                            And a last suggestion for the original poster: you're really taking a lot on yourself -- that's completely outside your control -- by contractually obligating yourself to jobs which will work with any printer. You're literally giving a printer who screws up a job license to blame it on you, and use their mistake to damage your reputation and take money out of your pocket. Even if it's not your fault. At the very least, you'll be spending non-billable time in a, uh, spitting match between a client's printer and yourself, in front of a client, with hard feelings all around if you win the conflict. At the worst, you'll be giving money and goodwill away for problems that may not even be your fault.

                                                                             

                                                                            I do jobs on contract too, so I know what it's worth to clearly spell out terms when you're working with an outside party. You didn't mention who sets the terms for your job to work with any printer. But if it's you, you really should delete that clause and take it out of your sales pitch. If it's your client(s), you should explain how hard it is to enforce and deliver on such terms, and negotiate your way out of them.

                                                                             

                                                                            Fair point. The purpose of this clause is to ensure that I send standards compliant files that any printer can understand and use without too many manipulations. It doesn't extend to the actual printing, but honestly, my clients are not half as invested in my work as I am, and if someday something goes wrong enough for them to complain, it will mean I probably did mess up and I will get emotional anyway.

                                                                             

                                                                            My company also outsources printing and I see every day awful PDF files coming out of big agencies. I know my suppliers are more than happy to take my files because they are dead simple to print in comparison. It helps create a trust bond with them and allows me to ask for example a priority on their planning when a client is desperately late, which helps create a trust bond with the client as well. There are advantages to take things on yourself, especially if you are a control freak like me.

                                                                             

                                                                            -

                                                                             

                                                                            rob day, actually, ISO Coated v2 is limited at 330% total ink if I can recall (there is a dedicated "ISO Coated v2 300%" profile). Interestingly, sometimes the total ink coverage overshoots the limit. There must be a tolerance, or maybe blending modes are not limited by the profile ? I have no idea.

                                                                            • 35. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                              c.pfaffenbichler Level 8
                                                                              Interestingly, sometimes the total ink coverage overshoots the limit. There must be a tolerance, or maybe blending modes are not limited by the profile ?

                                                                              When working in CMYK, in Photoshop or Indesign, the current color space’s TAC is irrelevant, it only comes into play at conversion.

                                                                              So if you had a Layer/object of 100/100/100/0 and a Layer/object of 0/0/0/100 atop that with Blend Mode Multiply you would indeed get 400% total ink. (unrealistic example but the principle applies)

                                                                               

                                                                              In Indesign one could force the flattening to be performed in RGB and followed by a conversion by setting theTransparency Blend Space to Document RGB (and the appropriate pdf settings) but would that ever open a can of worms – it would cause re-separation of affected CMYK elements and could for example cause primary and secondary colors to dirty up or pure black/gray to be converted to 4C-black/gray …

                                                                               

                                                                              So basically when working in CMYK watching that the TAC is not being overshot is up to oneself.

                                                                              • 36. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                                rob day Adobe Community Professional & MVP

                                                                                Would there be a way to make Indesign output a PDF/X-4 and then flatten and convert it to CMYK properly if a supplier asks for this format ?

                                                                                The default PDF/X-4 leaves color unchanged, but you can conform to the PDF/X standard and still convert all color to a specified CMYK space on export:

                                                                                 

                                                                                Screen Shot 2016-05-22 at 8.22.56 AM.png

                                                                                This produces a PDF that is all CMYK, but leaves transparency live. If you use transparency and flatten via PDF/X-1a, and send to a printer using Adobe's PDF Print Engine you would defeat its transparency capabilities:

                                                                                 

                                                                                Features

                                                                                 

                                                                                 

                                                                                 

                                                                                When I first noticed it I asked the printer "How come this gradient is broken ? what did you do ?" and they replied "It's not us, your file is like that !", and yes, the crappy gradient was on the file.

                                                                                 

                                                                                I think you have to be careful judging gradients from their screen preview, to get the preview there has to be a color conversion from the document's CMYK profile to your Monitor profile. That's not to say there couldn't be a problem with the blend, but if the blend prints correctly on one device and poorly on another then the problem is clearly with the output device—or some color conversion on the way to the device.

                                                                                 

                                                                                If I magnify my examples in #25 I can see the banding is caused by a color conversion. The yellow and black ramps are contaminated, which creates very noticeable banding. So if the printer is claiming the problem is in the file, you'll want to confirm that they printed the file's actual output values:

                                                                                 

                                                                                Screen Shot 2016-05-22 at 8.46.56 AM.png

                                                                                 

                                                                                No color conversion and no banding

                                                                                Screen Shot 2016-05-22 at 8.49.06 AM.png

                                                                                 

                                                                                I mean, at least I need to be able to use overprint 100% K on black texts ! How can I achieve that in an RGB document ?

                                                                                 

                                                                                You can't, but you could set the text over the RGB image in InDesign. There are cases where you might need to work in CMYK, but you also have to be sure there will be no conversions on the way to print otherwise the values you have set will be converted. At a minimum you should leave the Photoshop file untagged or set InDesign's Color Mangement Policy to ignore CMYK profiles.

                                                                                 

                                                                                There must be a tolerance, or maybe blending modes are not limited by the profile ? I have no idea.

                                                                                 

                                                                                There's no limit once you are in CMYK mode, which is another reason to delay the conversion. An RGB image could be output to newsprint profile at 240% or a sheetfed press at 350%. With CMYK you would have to provide separate files

                                                                                • 37. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                                  rob day Adobe Community Professional & MVP

                                                                                  but would that ever open a can of worms – it would cause re-separation of affected CMYK elements and could for example cause primary and secondary colors to dirty up or pure black/gray to be converted to 4C-black/gray …

                                                                                   

                                                                                  That will be a problem if you flatten via X-1a, but there is a work around with X-4, which will protect CMYK colors. See #25 in this thread.

                                                                                   

                                                                                  Re: How to make sure an ad prints well in magazine - Workflow

                                                                                  • 38. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                                    rob day Adobe Community Professional & MVP

                                                                                    and often using JPEG compression, which further reduces the colour depth, especially in subtle bright gradients...

                                                                                     

                                                                                    and they replied "It's not us, your file is like that !"

                                                                                     

                                                                                    Another variable you have to consider, which I don't think has come up in the thread, is the printer's minimum dot capability. if you are building blends that depend on values in the 1-5% range (around 25 levels of gray per channel) and the printer can only handle a 3-5% dot you are going to get very noticeable breaks as you hit each color's limit especially if there's black in the mix. That could explain why you see problems on the press sheet but not on the proof.

                                                                                    • 39. Re: Smooth gradients and feathers in PDF/X-1a ?
                                                                                      c.pfaffenbichler Level 8

                                                                                      Do you mean

                                                                                      The end result is flattened CMYK (Guido's printer's requirement), so if there's a problem you will see it in the numbers or the simulation preview.

                                                                                       

                                                                                      For all of the complaints of PDF/X-1a's age it does let you see the final output numbers (assuming no one intervenes and forces a color conversion downstream). The irony is that if I leave the PDF/X-4 as is, I have to release a PDF that shows total ink exceeding the limit by more than 80% and assume some (unknown?) operator will catch the problem and fix it without altering the color's appearance.

                                                                                      ?

                                                                                      Because you mention yourself that the TAC is  still being violated.

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