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Unfortunately, the well-known registry solution described for example here does not work when exporting to PDF.

With this registry hack, pages exported e.g as JPEG or PNG will be saved with a correspondingly high resolution -- in newer versions of PowerPoint even without the previous limitation to 307 dpi.

However, when exporting to PDF, all bitmaps contained in a PowerPoint slide are only embedded in the PDF at low resolution (200 dpi in my case).

It would be great if someone had the information where the bitmap resolution for PDF generation from PowerPoint is saved, so that this resolution could be increased.

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3 Answers 3

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Exporting to PDF takes a completely different path than exporting images, so the DPI registry hack that works for JPG et al will have no effect on PDFs.

Assuming you're using PPT's own Save As | choose PDF export rather than an add-in from Adobe or other PDF printer driver supplier, here are a few things that will have an effect:

Check File | Options | Advanced Scroll to Image Size & Quality Put a check next to Do Not Compress If the checkmark's not already there, any images you've already inserted will already be compressed; you'll need to delete and re-insert them.

If there are any empty Content or picture placeholders on a slide, delete them before you insert images; images inserted into placeholders WILL be compressed. Period. Regardless of your Do Not Compress setting. This may have been fixed in the most recent versions of PPT, so test first if you wish.

When saving your PDF, be sure to choose the Standard Publishing ...etc option

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    All of this I have tried already. Specifically, the images are not compressed in the PowerPoint file but of native resolution. Opening the PPT file e.g. in LibreOffice Impress and exporting it from there to PDF leaves them in their native resolution.
    – David.P
    Dec 8, 2020 at 19:07
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    To help understand this better, how are you determining that the files in PPT are still in native resolution and how are you measuring the resolution in the PDF? I know you can do the first by unzipping the PPTX and extracting the images. I don't know offhand how to do the second. Thanks!
    – Steve Rindsberg
    Dec 10, 2020 at 21:25
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    If I drag the images larger in PowerPoint and then zoom in, a high resolution is still visible. Likewise, when printing from PowerPoint to PDF, the images are still in high resolution. In summary, I haven't tried it exactly yet, but I strongly suspect that the images in PowerPoint remain in their original resolution with my current PowerPoint settings. The resolution of images in a PDF can be determined e.g. in PDF-XChange Editor with the function "Recompress Image", which shows all information about a selected image: i.imgur.com/S6k82Hx.jpg
    – David.P
    Dec 17, 2020 at 12:04
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    Other than suggesting that you turn image compression off rather than choosing High Fidelity (you'll have to delete then re-import the images after doing this), I'm at a loss.
    – Steve Rindsberg
    Dec 19, 2020 at 18:23
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    Ah, I see. I didn't catch that detail, David.
    – Steve Rindsberg
    Dec 21, 2020 at 15:29
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You can increase the effective bitmap resolution by increasing the slide size in PowerPoint.

For this, go to the Design tab > Slide Size > Custom Slide Size. Standard slide sizes for 16:9 slides are 13.33 in x 7.5 in - up these to 40 x 22.5 to effectively triple the bitmap resolution.

Ideally, you do this before starting your presentation. If you do not, PowerPoint will scale up the existing content (bitmaps, text etc.). In my case, most custom slide properties were maintained - only default font colors and enumeration symbols were lost, and margins did not seem to be scaled up.

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  • Thanks, that indeed seems to be the only way around this problem at the moment.
    – David.P
    May 27, 2021 at 8:28
  • This has the additional advantage that you can zoom in more on the slide while drawing, since PowerPoint limits the maximum zoom level.
    – David.P
    Jul 2, 2022 at 21:08
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Instead of Save to PDF you can print to PDF. this preserves the resolution of the images. File>Print>Choose PDF from the printer list>click printer properties and set the resolution (and paper size in custom if required). then press ok and print.

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  • That's true, however this does not preserve, inter alia, object transparencies. Instead, overlapped object areas are rendered with bad (pixelated) quality, even when the objects are vector objects.
    – David.P
    Sep 6, 2023 at 15:04

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