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Compare PDF files

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    • #60467
      alfredmosskin
      Participant

      Ahoy there,

      I am looking for a way to quickly and accurately compare two PDF files, and alert me for any inconsistencies. The situation is that I want to take the ripped pdf from the printer and compare it with the original pdf that has been approved by my client.

      Which tool would you say is the best to use? Acrobat's Compare Document funtionality? Promedia PDF Comparator? or do you have any other suggestions or experience, good or bad?

      Thanks!

    • #60472
      David Blatner
      Keymaster

      This has been covered in a couple of places. One option is to use software such as:

      https://www.premediasystems.com/pdfc.html

      You could use InDesign itself, such as in this blog post:

      indesignsecrets.com/document-differencing.php

      You can also see comments in this forum thread:

      https://creativepro.com/topic/indesign-native-files-and-pdf-comparison-86

    • #60485
      alfredmosskin
      Participant

      Thanks David!

      The first link you suggested on “PDF Comparator” is the one I have looked at very briefly. Any experience from it, compared to Acrobat?

      I did check the other threads and I think the indd-indd and indd-pdf suggestions are really cool, but in this case it is pdf-pdf. The approved against the printer's.

      It is also of course mostly a visual check than a technical/object-level check. If the printer's rip makes changes on a object or pixel level that is not really visible, this is not a problem. Problems are rather whole textblocks disappearing, big font changes, images and graphics moved or removed, etc.

    • #60486

      Why wouldn't you use Acrobat's own Compare PDFs menu command/routine?

      AM

    • #60500
      alfredmosskin
      Participant

      Dear Anne-Marie,

      Yes, that was my original intention as well!

      But frankly I am not a huge fan of it, having tried it from time to time. My guess is that it is most useful when you have the same export source of the PDF:s you are comparing, and have the same export settings. Otherwise I find it tends to focus on technical differences rather than visual differences, of course this is correct in a way, but at the end of the day you want the page to look right rather than have beautiful code. Checking the technical build up of the file is of course important and something I don't want to be without, but I think this should be handled by the truly awesome Preflight function in Acrobat.

      What I would like, just in case the Acrobat developers at Adobe are out there listening, is a compare functionality that skips the nitti gritty PDF code build up differences, but finds and highlights the visual differences. This would check the document page by page and highlight visual differences, in some nice striking accent color. After the comparison you would get a report listing the “difference ratio” per page, like Page3: 0% diff, Page4: 2% diff. etc. So then you can go back to the document and look at the pages that were reported different.

      I am thinking this maybe could be done comparing a lowres file with a highres file as well. Or an approved jpg proofing file with the final highres pdf.

      I think the closest match here is the “PDF Comparator” from Premedia Systems, as you suggested, David. When testing the trial version it seems to do the trick. Thanks for the advice, guys!

    • #60527
      Anonymous
      Inactive

      There are different levels you can get the compare the documents at – just as you describe.

      https://help.adobe.com/en_US/Ac…..160FF.html

    • #60549
      Alan Gilbertson
      Participant

      When I want to do a purely visual comparison, I usually do it by having both versions open at the exact scale and superimposed, then toggling them back and forth. The eye sees even tiny differences as movement, so they are very easy to spot.

      For a single or double-sided piece, opening both versions as layers in Photoshop, one below the other, is a slightly roundabout but very precise way to do this, since you can just drag the opacity slider on the top layer back and forth or use the “Difference” blend mode. It's all but impossible to miss a change, even things as subtle as minor letterspacing differences in body copy.

    • #61001
      erkki
      Member

      In Acrobat you have to look all the pages side by side. If you have a pdf with 500 pages, this can be quite time consuming. With Pdf Comparer you can compare pdf files easier because you don't have to look at pages where are no differences.

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