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arenol
Currently Being Moderated

Physical clipping of inserted PDF/EPS during export / Allow print to PDF.

Nov 16, 2011 4:43 AM

Tags: #pdf #export #indesign #printing #eps

We have a  challenge when producing map books, of which we regularly produce.

 

Such a book is typically laid out with several pages, with the same map file (PDF or EPS) placed several times with different windows in the document.  One Map file may occur  more than 20 times in the same InDesign document.

 

A problem is that InDesign doesn't clip the PDF instances to the frame while exporting to PDF, but rather outputs the entire PDF file allmost as is.

 

A solution would be to print to a PDF file using Acrobat Distiller.  But InDesign doesn't allow us to do that, promoting its own PDF-export (which generaly is excellent, except for this problem).

 

Thus, the output PDF files tends to become unnecessary large and heavy to process.

 

A possible workaround for us is to export the document pagewise to EPS and run those through distiller.  But this is also cumbersome with an unecessary step and then there's the problem with transparency flattening while exporting to EPS.

 

I assume that the easiest way to implement this feature in InDesign, is to allow printing to PDF-files.  OK, with a warning alert recommending InDesigns own PDF export.  Implement clipping in InDesign is of course much more heavy.

 

For us, the important thing is that we avoid the extra EPS-step with the transparency flattening.

 

Kind Regard

Agnar

 
Replies
  • Currently Being Moderated
    Nov 16, 2011 4:50 AM   in reply to arenol

    There  is a checkbox in the lower right corner of the Compression tab inthe export dialog marked "Clip Images To Frames" that should do exactly what you want.

     
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  • Currently Being Moderated
    Nov 16, 2011 5:55 AM   in reply to arenol

    Ah, yes. I suppose that would be true as vectors don't get compressed.

     
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  • John Hawkinson
    5,572 posts
    Jun 25, 2009
    Currently Being Moderated
    Nov 16, 2011 6:32 AM   in reply to arenol

    Agnar:

    A solution would be to print to a PDF file using Acrobat Distiller.  But InDesign doesn't allow us to do that, promoting its own PDF-export (which generaly is excellent, except for this problem).

    You can also print to a PostScript file from InDesign, and distill that with Acrobat Distiller.

    Is that what you meant to say?

    But InDesign does allow you to do that.

     

    It is disrecommended, though, because it is designed for printers, and not designed to produce device-independent output. But it does work.

     

    I wasn't aware that Acrobat Distiller clipped artwork in this fashion, but I'm going to assume that you are correct that it does.

     

    Really, this seems to me an odd requirement. What sort of file sizes are we talking about here, I wonder? I suppose pre-cropping the files would be an inconvenient workflow.

     

    I assume that the easiest way to implement this feature in InDesign, is to allow printing to PDF-files.  OK, with a warning alert recommending InDesigns own PDF export.  Implement clipping in InDesign is of course much more heavy.

    Well, to print to PDF files would require leveraging the operating system's support for same. Prior to MacOS X 10.6, this was in fact an option. See http://kb2.adobe.com/cps/509/cpsid_50981.html. Because of security changes to the OS, allegedly, this feature stopped working and Adobe removed support for it. I think this is also because it was a workflow that caused problems for people who tried it, and most of the people who used the workflow selected it for the wrong reasons, and should have been using another workflow.

     

    Peter writes:

    Ah, yes. I suppose that would be true as vectors don't get compressed.

    Well, that's not really true at all. Vectors are basically text and lists of numbers, and those are highly compressible. But clipping them is a much more complicated operation than simply compressing.

     

    It would also seem like the sort of thing you might be able to post-process the PDF to deal with. Agnar, would a solution that involved postprocessing with Acrobat Pro be helpful to you? I am hardly an Acrobat Pro expert, but I'd give it 30/70 odds that there is a way to clip vector images on an existing PDF file without extensive programmatic/scripting work. (Asking in the Acrobat forum would be best.)

     

    Another bad workflow you could use would be to convert the InDesign PDF to PostScript and then feed that through Acrobat Distiller -- so-called "refrying" the PDF. That's [probably] worse than InDesign's PostScript output followed by Distiller, and is certainly a disrecommended workflow in any case. Call it a "last ditch workaround" for some problems.

     
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  • Currently Being Moderated
    Nov 16, 2011 6:55 AM   in reply to John Hawkinson

    John Hawkinson wrote:

    Peter writes:

    Ah, yes. I suppose that would be true as vectors don't get compressed.

    Well, that's not really true at all. Vectors are basically text and lists of numbers, and those are highly compressible. But clipping them is a much more complicated operation than simply compressing.

     

    I probably should have said something like "that panel doesn't apply to vectors" because the clipping reallyhas nothing to do with the compression, as far as I know.

     
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  • John Hawkinson
    5,572 posts
    Jun 25, 2009
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    Nov 16, 2011 7:00 AM   in reply to Peter Spier

    Still doesn't save you, I'm afraid, since clipping certainly does apply to vectors

     
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  • Currently Being Moderated
    Nov 16, 2011 7:33 AM   in reply to John Hawkinson

    I'll take your work for it. I'm just a lowly designer.

     
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  • Currently Being Moderated
    Nov 16, 2011 12:22 PM   in reply to arenol

    Some general observations about this whole discussion:

     

    (1)     EPS and PDF are containers for content other than just images. As far as I know, InDesign's PDF export option for clipping placed content relates to image-only content such as you would get from TIFF, JPEG, etc.

     

    (2)     Output to PostScript from InDesign isn't any more efficient in regards to such clipping than PDF export and certainly not for non-image data.

     

    (3)     The Distiller has no optimization for clipping InDesign's placed content; it doesn't even know what “placed content” is and even if it did, it could conceivably only deal with image data!

     

    (4)     If the map file in PDF or EPS is indeed just an image, you might want to what happens if you use TIFF instead and apply the clip option when exporting. That may help.

     

    (5)     Having the image at different magnifications and thus different effective resolution and triggering different downsampling may defeat a mechanism both in PDF export and in the Distiller to recognize identical images and define them only once in the resultant PDF file. The same thing happens with clipping. If you don't clip and if there is no downsampling on PDF export (or PostScript creation), PDF export (or the Distiller) can optimize by recognizing multiple instances of the same image and have only one definition of same in the PDF file. If an image is clipped 20 different ways (even at the same magnification) during PDF export (or PostScript creation), it looks like 20 different images and no optimization is or can be applied since there are effectively 20 different images.

     

    Clear as mud? 

     

              - Dov

     
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  • John Hawkinson
    5,572 posts
    Jun 25, 2009
    Currently Being Moderated
    Nov 17, 2011 6:05 AM   in reply to arenol

    Are you aware that EPS is a type of PostScript? I don't think there is any case where exporting pagewise as EPS confers benefits over exporting the document as PostScript (but there are many subtleties around this! I am very prepared to be wrong! I only give you my guess without extensive detailed testing!). I would expect the same transparency limitations from EPS.

     

    Have you tried InDesign's PDF export with export settings that tell is *not* to resample the included images? Hopefully that would prevent the image duplication algorithm from being defeated, giving you a PDF that's no larger than 5*200MB => 1GB in terms of included images.

     

    If you are included 5 files each 200mb, regardless of how many times (you said 20), 1GB would seem to be your minimum size anyhow, unless you are downsampling. And if you are, it would seem like you could just start

    with lower resolution artwork to begin with. Watch out for Nyquist.

     

    Also: What Dov said. He is really an expert on these things and you are unlikely to hear from anyone better!

     
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