26 Replies Latest reply on Dec 31, 2011 8:03 AM by John Hawkinson

    InDesign, PDFs and re-sizing images ...

    aliciasdad

      I've just completed a photo book in InDesign and am ready to export it as a high-rez PDF and send it to the printer.

      All of the original images are 300dpi.  The original images, where needed, were all re-sized to fit either a spread in the book or a full single page (vertical).

      But quite a few of the images that have been imported to the InDesign document have been made smaller than a full page spread or single page within the InDesign document itself.  Some are 70% smaller than full page or full spread.  The original JPEGs and/or TIFFs were not resized.

      The InDesign document, then, is linking to an original size image ... even though the same image in the InDesign document may be smaller as well as cropped somewhat.

      So my question is: before creating the PDF, do I need to go back to the original JPEGs, resize/crop them to match what I've laid out in InDesign and then re-import them?  I hope not.  That feels like nearly having to start all over!  I've searched extensively for an answer to my question, but I've not found anything even remotely close to this topic.


      As a test, today I created one complete PDF straight from the InDesign file (almost 200 pages), and it looks really good ... 99% close to the original images.  But with images that have been reduced as much as 60-70%, I'm seeing a slight loss of detail and some plugging up in the shadows; not much, mind you ... but enough to cause me some concern.  I believe the reduced images are losing a touch of crispness.

       

      I know if I were doing a straight size reduction in Photoshop and saving a pic as a resized JPEG or TIF image, I'd be re-sampling and brightening the reduced image (a little), adding some local contrast, adding micro contrast, etc to compensate for the lost data.  Seems to me the same thing needs to be done with images made smaller within InDesign.  Then again, maybe not.

      Your experienced advice and suggestions are very welcomed.  Thanks in advance.

        • 1. Re: InDesign, PDFs and re-sizing images ...
          Peter Spier Most Valuable Participant (Moderator)

          Forst off, try using Zip compression instead of jpeg when you export. That may be enough to make the difference. If not, you probably want to go to Photoshop and resize, the tweak the images. The resampling you get from ID during export is the same as you would get in photoshop, but you don't get the opportunity to fix things.

          • 2. Re: InDesign, PDFs and re-sizing images ...
            aliciasdad Level 1

            Thanks for the response Peter.  I'm not sure what you mean by using Zip compression to "make the difference."  What "difference" are you referring to?

             

            Good to know that re-sizing within InDesign during export does re-sampling.  I wasn't aware of that.  Thanks again.

            • 3. Re: InDesign, PDFs and re-sizing images ...
              John Hawkinson Level 5

              Alicia'sDad: As I read your original post, I have a lot of trouble telling what your real question is.

              You make a lot of statements and sound very confused?

              Re-reading several times, I gather your concern is that the image quality in your PDF output appears to be degraded? Is that correct?

               

              If so, you should tell us how you are viewing the PDF file (on paper? viewing it on-screen or printing it from Adobe Reader? From Acrobat Pro? From Preview.app? Non-Adobe software has been known to do bad things to PDF quality.)

              What are the actual and effective PPI of the images in question?

               

              You write:

              So my question is: before creating the PDF, do I need to go back to the original JPEGs, resize/crop them to match what I've laid out in InDesign and then re-import them?  I hope not.  That feels like nearly having to start all over!  I've searched extensively for an answer to my question, but I've not found anything even remotely close to this topic.

              You should not have to do this. Certainly unless you have some higher-resolution source material, you are unlikely to get significantly different downsampling from Photoshop than InDesign will produce.

               

              But also, tell us your output device. What kind of resolutions are we takling about? If you're printing, say, a 300ppi black and white image on a 300 dpi laser printer, you should realize that a 300dpi laser printer can only produce about 60lpi because of halftoning, so a 300ppi greyscale image won't look much different than a 100ppi greyscale image on paper. Etc. (Though on screen is very very different.)

               

              Good to know that re-sizing within InDesign during export does re-sampling.  I wasn't aware of that.  Thanks again.

              Carefully read the settings in the PDF Export dialog. All things being equal, you should probably use the PDF/X preset.

               

              Thanks for the response Peter.  I'm not sure what you mean by using Zip compression to "make the difference."  What "difference" are you referring to?

              When you export to PDF, you have settings like this:

              downsample.png

              It's hard for me to imagine you are in a situation where this really matters, so I'm a bit skeptical. But depeannding on setting here, InDesign will do several things. It will resample your images to a reasonable ppi for a decent output device (e.g. a 1200ppi/200lpi imagesetter or comparable), and it will compress them. The default compression is JPEG, which does mean that it can introduce compression artifacts. If you change the compression to ZIP, then there will be no compression artifacts because ZIP is a lossless compression. The compression will also be less effective, so your file size may increase, but that's probably not a problem or real consideration.

               

              p.s.: I think it's best to keep the font size in your posts the default. If everyone made their posts bigger it'd just be weird.

              • 4. Re: InDesign, PDFs and re-sizing images ...
                aliciasdad Level 1

                Yes, I made a lot of statements, but I'm not confused.  Just wordy.

                 

                And you have definitely provided an answer to my question, ie whether or not I have to go back to the original JPEG files and re-size them according to the way the images are sized and cropped within InDesign.

                 

                It looks like I don't have to.  I also hadn't been using the PDF/X preset.  I'd configured my own custom, high-rez preset with no compression.  I'm going to create another PDF with the PDF/X 2004 setting and see how it looks and prints.

                 

                As far as my output device goes, I've been printing the high-rez PDFs on an Epson 3800 using a RIP.  The paper is Epson's commercial proofing paper.  I don't know my printer's output device.  All I know is that they have requested a high-rez PDF and all images at 300dpi.  I've had samples of my images printed by them beforehand on the paper to be used for my book.  The samples are very sharp, very clean, very rich.

                 

                Thanks for your help and your reply.

                • 5. Re: InDesign, PDFs and re-sizing images ...
                  Peter Spier Most Valuable Participant (Moderator)

                  Your Epson proofs are probably at 1440 dpi, the press output at double that, so it should have better detail.

                  • 6. Re: InDesign, PDFs and re-sizing images ...
                    aliciasdad Level 1

                    You're correct.  I've been printing at 1440, a reasonable setting for determining IQ.  Like yourself, I've assumed that the printer's setting is 2880.

                    • 7. Re: InDesign, PDFs and re-sizing images ...
                      Peter Spier Most Valuable Participant (Moderator)

                      Of course, it isn't entirely that simple, and we can't tell for sure without a bit more information what is the most likely outcome. The printers are asking for 300 ppi, which implies a pretty standard coomercial output in the range of 150 lpi on the halftones (you could probably squeeze 200 lpi out of it, but most printers would ask for a little more resolution for that. I think).

                       

                      Resolution is only relevant at the print size, not the size the file is saved. In other words, the resolution after scaling (and after export, if you choose to downsample). ID refers to this as the "effective" resolution, and you can see it in the link information and the Info panel. You said you had high resolution images, but didn't say how high, and you've scaled them, so presumably the effective resolution may be well above the 300 ppi target. Normally this poses little or no problem, but if the effective resolution is many times more than required you might start to see some loss of fine detail. The RIP will only use as much of the image data as it needs to create the half-tone, and of course downsampling also throws away some pixels. If you have detail that is only a single pixel wide you have a good chance of losing it under this scenario. Using jpeg compression can, as John noted, add some compression artifacts and interpolated colors that can further obscure fine details.

                       

                      There is no perfect answer here. Zip compression will help with the artifacts, but not with any pixels that might be thrown away, and the quality of the printed image is highly dependent on both the paper stock and the printing method (along with the skill of the printer). Generally speaking, though, your finished book out to look as good as or better than the Epsons.

                      • 8. Re: InDesign, PDFs and re-sizing images ...
                        aliciasdad Level 1

                        Peter: all of the original images are 300ppi/dpi with a physical size of either 9 X 12 (verticals) or 18 X 12 (spreads).

                         

                        The effective resolution of some of the scaled images (scaled down or cropped in ID) is as high as 720ppi/dpi.  Some may even be higher than that.  I haven't yet viewed the info on all of them.

                         

                        I intend to resize/resample any original image that has turned out to have an effective resolution in ID of more than 550ppi/dpi. 

                         

                        Thanks for your help.  Very much appreciated.

                        • 9. Re: InDesign, PDFs and re-sizing images ...
                          John Hawkinson Level 5

                          [ Edit: This message crossed with reply #8, and was written before I saw it. ]

                           

                          I definitely need to defer to Peter on this, his experience is much more suited to this sort of output device.

                           

                          But I would say, shooting from the hip:

                          • We're still waiting for you to tell us the effective PPI involved.
                          • Always talk to your printer.
                          • If your proofs show problems, you should not assume that your final output device will not! You are right to worry.
                          • Are you using the same RIP that your final printer will use? [What RIP are you using?]
                          • What linescreen is your Epson using and what linescreen will the final output be at?
                          • How does your output look if you print it at 200% on your Epson?

                           

                          On the other hand:

                          It looks like I don't have to.  I also hadn't been using the PDF/X preset.  I'd configured my own custom, high-rez preset with no compression.  I'm going to create another PDF with the PDF/X 2004 setting and see how it looks and prints.

                          Well, then assuming you really turned off compression and not simply downsampling, obviously moving to ZIP compression is not going to help you. So you should be concerned, because it seems like something is wrong.

                           

                          Maybe you should indeed downsample a single image (as a test!) in Photoshop and re-place that image in a copy of the InDesign file, export that one page to PDF, and print it on your proofer. Easy to do, and it will tell you something.

                          • 10. Re: InDesign, PDFs and re-sizing images ...
                            Peter Spier Most Valuable Participant (Moderator)

                            John Hawkinson wrote:

                             

                            • If your proofs show problems, you should not assume that your final output device will not! You are right to worry.

                            I would agree with this to a point. It depends on the sort of problem or the severity. At 1440 dpi, you probably are not introducing errors that will disappear at 2880, but it certainly is possible. When looking at the Epson proofs you should be looking for color and tonal range -- if those are good, the final print should also be good (presuming the color profiles are accurate). The image setter or plate setter will be able to reproduce at least as many shades as the Epson. On the other hand, if the images look pixelated (presumably not a problem here), they won't get better, and truly plugged shadows will probably remain plugged, as will blown out highlights. Keep in mind, though, that the level of detail and the number of shades that can be produced for any image on any particular device are inversely related, at least for conventional haltones. Halftone spots are built from a matrix of printer dots, so the more printer dots that are in each spot the higher the number of shades that can be produced, but the larger the minimum size of any hairline details. The image setter has 4 times the number of dots availble as the Epson.

                             

                            " But with images that have been reduced as much as 60-70%, I'm seeing a slight loss of detail and some plugging up in the shadows; not much, mind you ... but enough to cause me some concern.  I believe the reduced images are losing a touch of crispness."

                             

                            My initial reaction to this was that downsampling was being used during the export, which could certainly cause this, and in my opinion jpeg compression would possibly result in some shadow degradation, too, but if there was no downsampling it's probably the result of the RIP using only part of the data -- as I said above, images that are significantly larger than required may show loss of detail simply due to throwing away data. I don't think there is any cure for this, it's just the nature of images -- only so much detail you can cram into a particular space. At the extreme try making an icon out of a detailed photograph and you won't recognize it. Whether the press output will look better than the Epson will depend on if the plates use conventional halftoning or stochastic screening, the line screen, and the paper, presuming that the inks remain in register on the press and the Epson. An uncoated paper, for example, is almost certain to look a little soft compared to the Epson because of dot gain.

                             

                            For anything that looks marginal, John's advice to ask the printer is definitely the way to go.

                            • 11. Re: InDesign, PDFs and re-sizing images ...
                              aliciasdad Level 1

                              Peter: thanks again.  Your responses are extremely helpful, informative and ... perhaps more than anything ... they provide a reasonable degree of confirmation that my book will turn out ok.  My Epson proofs are all excellent ... including those printed from PDFs exported from the original ID document as well as those with some high ISO noise (some of the images were shot at ISO 3200 on a Canon 5D and Canon 1Ds II).  The images printed directly from Photoshop via the Colorburst RIP really don't appear to be all that much different/better than the PDFs, though there are definitely differences.   I consider them insignificant.

                               

                              The acid test for me was when I sent the printer 6 PDFs of 6 original images for test printing on their device with their paper.  I was pretty surpised at how good the PDF prints were.  They were actually sharper than my originals.  Two of them had an effective resolution almost double the originals (550ppi vs. 300ppi) and still turned out looking ok ... except for the noticeable plugging up of the midtones and darker shadows.  I'm actually thinking of compensating for this in my JPEGs and lifting the midtones and shadows slightly.  That's always risky, but I think a slight curve adjustment will help things where needed.  Other than the plugging, I saw no objectionable artifacts, no sharpening halos, no dramatic color shifts, no loss of highlight detail, etc.  Pretty good!

                               

                              As mentioned, I'm going to re-size/re-sample original images that have been reduced in ID and whose effective resolution is really too high for my comfort.

                               

                              Thanks again.  I'm glad I posted here!

                              • 12. Re: InDesign, PDFs and re-sizing images ...
                                Peter Spier Most Valuable Participant (Moderator)

                                I'm not all that surprised that they were sharper. As I mentioned above, smaller halftone spots means you can get sharper details.

                                 

                                Your shadow and highlight darkening may be natural, too. Are you familiar with the concept of dot gain? Think of a drop of water and what happens when it hits a piece of tissue paper. The darker the shade, the more ink is in each spot, and the greater the effect of dot gain, which is to darken the print. Your color profiles should compensate for this, if they are accurate, but it's not at all uncommon for the monitor to be a little too bright and for everything to look brighter on screen than it will in print, so doing a few tests is actually a really good idea if you are hypercritical. I did a museum catalog last summer for a living artist (and I've never met anyone more hypercritical), so we did a test sheet with about 80% of the fetured paintings. I'd done the corrections on my laptop in his gallery/studio, but half the images needed more adjustments when we saw the sample. If you do a lot of this kind of work you'll start to have a seat-of-the-pants sort of feel for when it really is right, even if it seems wrong on screen.

                                 

                                I think I mentioned originally that unless you are going to do more than just resize I wouldn't bother going back to Photoshop. I would definitely do it, though, if you intend to also do minor color adjustments and sharpening after the resize.

                                • 13. Re: InDesign, PDFs and re-sizing images ...
                                  aliciasdad Level 1

                                  Peter: I'm from the "old school" (pre-digital), where compensating right from the beginning of a project was standard practice for offsetting the altering effects of printing.  This was partiularly true when shooting an image that was going to end up in a newspaper ad ... what with all that coarse screen and lack of real black.  I have no hesitation in using my best judgment for adjusting the curves of an image so it synchs with the output device, paper and even the printer's own style.  I have about 15 images that I'm definitely going to work on to boost the midtones ever-so-slightly.   When I mentioned the plugging up to the printer, his response was, "Oh ... we'll just brighten things up a bit when we get to printing the actual book."  I told him that I didn't think that was an effective solution 'cause that idea would blow some highlights as well.   He agreed and left the solution up to me.  Thanks again for your input.  I'm enjoying the exchange.

                                   

                                  - Steve

                                  • 14. Re: InDesign, PDFs and re-sizing images ...
                                    Peter Spier Most Valuable Participant (Moderator)

                                    OK, so you know exactly what I'm talking about. We never know about users' experience levels unless they tell us.

                                     

                                    And it has been an interesting conversation.

                                    • 15. Re: InDesign, PDFs and re-sizing images ...
                                      aliciasdad Level 1

                                      Yeah ... I go way back.  I spent most of my adult life in the advertising and design industries.  No regrets.  I had a great time and worked with some great people.  I've worked for some really exceptional ad agencies, like Chiat/Day, Doyle Dane Bernbach, Y&R, etc.  Worked for AOL during their "burst years," 1993-1998.  Even met Steve Jobs in 1985 when I started freelancing ... just as he was on his way out of Apple for the next ten years.  I turned my attention to photography full time in 2006.  Never looked back.  I photograph interiors for magazines ... big homes ... some of them 12-20,000 square feet.

                                      • 16. Re: InDesign, PDFs and re-sizing images ...
                                        John Hawkinson Level 5

                                        A few more notes:

                                        The acid test for me was when I sent the printer 6 PDFs of 6 original images for test printing on their device with their paper.  I was pretty surpised at how good the PDF prints were.  They were actually sharper than my originals.  Two of them had an effective resolution almost double the originals (550ppi vs. 300ppi) and still turned out looking ok ... except for the noticeable plugging up of the midtones and darker shadows.  I'm actually thinking of compensating for this in my JPEGs and lifting the midtones and shadows slightly.  That's always risky, but I think a slight curve adjustment will help things where needed.

                                        You don't mention how the Printer's [on-press?] proofs compare with your own Epson proofs, which might be helpful information. It may certainly be the case that their dot gain characteristics are quite different, and it sounds like you are not using a color managed workflow.

                                         

                                        With respect to compensating in your JPEGs:

                                         

                                        1. If you are really concerned about quality, you should not be using JPEG as a format. If you have JPEG originals, convert them to TIFF (or PSD) before doing any image operations on them. Repeated image operations on JPEGs do not degrade gracefully, and JPEG compression is never a good thing.

                                         

                                        2. You should not be shy about compensating for press effects. That is absolutely a necessary step. Sometimes that compensation is automatic, as with the use of proper color profiles in a color-managed workflow. Some times it is not, as with manual compensation.

                                        • 17. Re: InDesign, PDFs and re-sizing images ...
                                          aliciasdad Level 1

                                          John: I mentioned in a previous post to yours how my Epson proofs and the printer's proofs compare ... bottom line: very close.  And I am using a color-managed workflow.  What I see on my screen is what I get out of my printer ... unless you mean something else by "color managed."  My main monitor is an Apple 30" with an Apple 23" to one side for expanded desktop room.  The 23" is nowhere near as accurate as the 30", regardless of how many times I calibrate it.  But it serves its other purpose nicely.

                                           

                                          Regarding JPEGs:  I do all of my adjustments in TIFF files converted from RAW.  Once all adjustments are made, I convert to JPEG in order to get the file sizes a little smaller.  JPEGs, by the way ... so long as they're always saved at maximum quality ... can take as many as 15-20 "Save As" actions before noticeable degradation begins to set in.  Setting that "quality slider" to less than 12 and certainly to 9 or lower is where degredation begins a lot sooner.  Still, I do all of my serious work in TIFF.  There's no doubt lossless files are better than JPEG files in the long run.

                                           

                                          No, I'm not shy about compensating for press effects.  Standard practice where I come from.  See my previous post.

                                          • 18. Re: InDesign, PDFs and re-sizing images ...
                                            MW Design Level 4

                                            I don't see the benefit in JPEGs. Sure, they compress more than LZW compressed TIFFs, but when loaded into memory in a doc, both are decompressed. All it really gains in a "semi-lossless" JPEG workflow is savings on disk space.

                                             

                                            Take care, Mike

                                            • 19. Re: InDesign, PDFs and re-sizing images ...
                                              Peter Spier Most Valuable Participant (Moderator)

                                              I would have to agree, and it actually doesn't save disk space unless you also discard the original tiff. I tend to do all my edits on .psd files, and place them directly. Drive space is cheap these days.

                                              • 20. Re: InDesign, PDFs and re-sizing images ...
                                                John Hawkinson Level 5

                                                And I am using a color-managed workflow.  What I see on my screen is what I get out of my printer ... unless you mean something else by "color managed."

                                                A color-managed workflow is one where not only are your screens calibrated but also the output devices -- your desktop printer, proofing printer,  and your Printer's press. If that's the case and it all works properly, and you have the proper color profiles (a lot of ifs), then your proofing to your Epson proofer should almost exactly like your Printer's on-press proofs with respect to dot gain and similar effects. You would need to have received a color profile for your final output device in order to properly simulate it on your proofing device, though, if my [somewhat incomplete] understanding of color-managed workflows is correct.

                                                • 21. Re: InDesign, PDFs and re-sizing images ...
                                                  aliciasdad Level 1

                                                  Peter: I have never worked with .psd files.  Are there advantages with ,psd?

                                                  • 22. Re: InDesign, PDFs and re-sizing images ...
                                                    Peter Spier Most Valuable Participant (Moderator)

                                                    PSD is the native format for Photoshop, and is fully supported for import into ID (if you have vector content, like type that you want to keep live, save as Photoshop PDF instead, but I think you probably don't have that in your work). Are there advantages over TIFF? I'm sure there are some things that Photoshop can do that are not supported in TIFF, but off the top of my head I can't tell you what they are. I've generally had an aversion, though to saving layered or transparent TIFFs, though that may hark back to working in other layout apps that don't support them. I tend to use a lot of non-destructive adjustment layers in my photo editing, so leaving the files as .psd seems like a no-brainer to me, but I don't suppose it's critical.

                                                    • 23. Re: InDesign, PDFs and re-sizing images ...
                                                      aliciasdad Level 1

                                                      When all is said and done:

                                                       

                                                      I spent a few hours today re-sizing original TIFF files to match the size and cropping of the same files that had been imported in ID and adjusted there.  The original TIFFs were all 300ppi and at least 9" X 12".  Some of the ID equivalents were as small as 3" wide and had an effective resolution of over 900ppi!

                                                       

                                                      I re-imported the images, did some minor brightening, applied a tad of USM, made new high-rez PDFs of the revised pages, and printed at 2880 on my Epson 3800.

                                                       

                                                      My wife and I could hardly see any difference.  I mean, you really had to look hard, even when the effective resolution was almost triple the original 300ppi.  On those images where I could see a difference, it was negligible if not irrelevant.

                                                       

                                                      I think I firmly answered my own question. 

                                                      • 24. Re: InDesign, PDFs and re-sizing images ...
                                                        John Hawkinson Level 5

                                                        I have to say, I am surprised by the extent to which you sound surprised by your conclusions :).

                                                        • 25. Re: InDesign, PDFs and re-sizing images ...
                                                          aliciasdad Level 1

                                                          I'm surprised you're so surprised at my being suprised by the surprising conclusion I've come to.

                                                          • 26. Re: InDesign, PDFs and re-sizing images ...
                                                            John Hawkinson Level 5

                                                            Perhaps, then, you should tell us why you're surprised?

                                                            Because I think you should not be surprised.

                                                            I wonder if you have a misconception we should consider

                                                            correcting?

                                                             

                                                            Happy New Year's Eve!