When exporting from PowerPoint to PDF, how do I increase bitmap image resolution?
Matthew Harrington 
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.
2 Answers
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
12You 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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