I have a file in InDesign with two layers, each with a different version of the same graphic. The graphics in each layer are png files and they are basically exactly the same image except that one has lettering in English and the other has lettering in Spanish. The file size of each png is almost exactly the same (a few kb of difference between them). I want to create a PDF for each language, however one of the exported PDFs is twice the file size of the other and I cannot for the life of me understand why! The only difference between the two PDFs is the png image, but the original pngs have basically the same file size. So I cannot figure out why there is such a big difference in output file size between the two PDFs, generated from the same InDesign file! I export each PDF with exactly the same settings. I have tried clearing the cache, restarting, but it is same problem every time I export the two pdfs. Can anyone shed any light on what might be causing this? Thanks!

  • 4
    Could it be that the larger PDF includes both PNG images? Try turning off the visibility of the bottom layer, because although you may not see it, it is being included.
    – MG_
    Commented Apr 26, 2021 at 11:50
  • Thanks for the reply. No, the other layer is definitely invisible on export.
    – Sarah
    Commented Apr 26, 2021 at 12:51
  • 1
    There may be something different about the PNG images that you are not aware of. For example check the image modes of the PNG, are they Indexed, or RGBa? When exporting as PDF are you adding compression? What pixel dimensions are the original PNG images? What are your PDF export settings?
    – Billy Kerr
    Commented Apr 26, 2021 at 16:04
  • What is the file size of the two PDFs? One might be twice the size of the other, but if they are very small it might not be so strange. Have you tried just as a test to make two similar documents, one with each PNG, export PDFs and compare them?
    – Wolff
    Commented Apr 26, 2021 at 16:42
  • Maybe also just confirm that there's definitely only one per layer, by twirling down the chevron in the layers panel.
    – MG_
    Commented Apr 28, 2021 at 11:48

3 Answers 3


Colour profiles such as the "Iso Coated v2" have about 2.5 MB. Maybe a profile is applied in the pdf export presets.

  • Thanks for the suggestion, but the export settings are exactly the same for each PDF
    – Sarah
    Commented Apr 26, 2021 at 15:49
  1. Check if you have any leftover artwork outside the pages on any of the layers.
  2. Try exporting the EN and ES with the PNGs removed, obvioulsy without saving the INDD file. If you still get the file size difference, the problem is not in the PNGs.
  3. Otherwise, there must be something different in the PNGs. Check transparency, pixel size, etc.
  • Thanks - no artwork lurking anywhere, and when I tried your second suggestion the PDFs are both the same size, so the problem definitely lies with the pngs.
    – Sarah
    Commented Apr 26, 2021 at 15:51
  • Then, there must be something different in the PNGs. Check transparency, pixel size, etc.
    – Lucian
    Commented Apr 26, 2021 at 15:58

PDF is not just a file format, it is a container. It can contain raster images, vector shapes, text, and fonts (among other things).

If your PDF weights double it is either because of different compression parameters (which sounds it is not the case) or simply has more information.

So you need to check the PDF to see what additional information it has.

Open it in Illustrator and remove the elements to see what elements are there.

I would suspect that the second raster image is below the first one.

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