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anneroku
Participating Frequently
August 31, 2010
Answered

Why does printer need a flattened file when there is no transparency?

  • August 31, 2010
  • 1 reply
  • 29286 views

I sent a pdf of an AI file to a digital printer to preview before sending out to print.  In the email I received from the printer, I was told that this pdf was "transparent (meaning more than one layer) and needed to be flattened." (Quotes are taken directly from the email.)

I am puzzled about this because there was no transparency anywhere in the original file.  Yes, the original AI file had three layers, but it was all flat, solid vector artwork, no transparency or transparency effects anywhere.  Nothing that normally needs to be flattened.  It will all be printed CMYK, and my understanding is that the printer will eventually convert the whole thing to a .tif file.

I am awaiting a response from the printer and have read all I can about flattening to see if I am missing something.  In the meantime, can someone tell me if this is a common request from digital printers?  Am I missing some important concept regarding flattening?  Thanks!

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    Correct answer _scott__

    Thanks, that's helpful.

    I still don't understand what flattening non-transparent artwork actually does to it, though.  I generally understand what is going on when transparency is flattened, but how does flattening affect non-transparent art?  Is the only difference then that the transparent layer you mentioned disappears?  (And where exactly is that transparent "no background" layer?)


    All Illustrator files have no background - EPS - AI - PDF.

    When you place them into Indesign or Photoshop do you see a white background?

    No. That's because there is always a hidden layer of transparency.

    You can't see or edit this transparency layer, it's simply there.

    When you flatten artwork in say a PDF, the application it adds a white background assuming white is the color of the stock it will be printed on. Traditional mechanicals were all done on white paste-up boards because copy cameras don't see white. The same theory is used in software today - white = transparent or not seen.

    1 reply

    _scott__
    _scott__
    Legend
    August 31, 2010

    PDF 1.4 (Acrobat version 5) or greater supports layers. This is probably what needs flattened. FLattening does not automatically mean there is transparency. The flattening could simply refer to the layers.

    Save your PDF as PDF1.3 (Acrobat 4) and it will be flattened upon saving. You might even consider using PDFX-1a which is a press-ready flattened PDF format.

    A
    annerokuAuthor
    Participating Frequently
    August 31, 2010

    If the printer wants no layers, what if I just manually move everything to a single layer?  Would this give a different result than flattening (for a file that has no transparency)?

    A
    annerokuAuthor
    Participating Frequently
    September 1, 2010

    Nothing within Illustrator will remove the invisible transparent layer. It's only removed upon export, printing, or saving to some formats.

    Honestly, I've never used the Flatten Artwork, or Flatten Layers commands. There's never been a reason to. But.. if I were to use it, the only reason would be to make future editing of a file as difficult as possible. I.E. Flatten layers, select all, pathfinder merge, save as eps.


    OK.  Thanks for explaining.

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