I received a few PDF files from my co-workers and I'm trying to print them. The problem is that these files are taking unbelievably long to print (up to 30 min on a 50 pages file). I know that these were originally PPT presentations, and that they produced this PDF files using the Publish to PDF feature in PowerPoint 2007/2010.

The files are not large in size (between .5 and 7 MB).

I've tried printing on both a Windows and a Linux machine. On the Windows machine the process stalls right after I press OK on the print dialog. A new dialog pops up in Adobe Reader saying Flattening: [Page Num] [Percentage Done] (exact wording might be imprecise, as my Windows is not in english). This dialog has no Cancel button, takes around 30 seconds to complete (there`s a progress bar), and a new one pops up for each slide. This causes the printing job to take almost half an hour before being sent to the printer.

On the Linux machine a very similar thing happened. When I send the document to the printer (either from evince or from the command line) there is a 20 min stall before the printer actually gets it. Close examination revealed that during this time the system is converting the document to a printable format (with pdftops). I also tried doing this manually, and I noticed the PS files being generated from the PDF are extremely large (around 300MB).

This is not then first time I've printed PDF slides, but it's the first time I've come accross this problem (the Flattening dialog box was completely new to me). Is it normal for ppt slides to take so long to print when converted to PDF? Is there anything I can do about it to reduce my waiting time?

1 Answer 1


This looks like your PDF makes heavy usage of the transparency feature which the PDF graphic model supports.

Hence the Flattening: [Page Num] [Percentage Done] message you are seeing for each slide. It indicates that the transparent objects are being re-computed into a pixel picture which contain all of the transparent objects stacked upon each other, plus their "underground".

It is "normal" for PPT slides turned to PDF to take a long time for printing if the original transparency has been transferred into the PDF.

To avoid the problem, try to produce PDFs which have the transparency "flattened" from the beginning. (Or apply posterior transparency flattening to the PDF you already have.)

Note: the flattened PDFs will most likely be larger than your original PDFs, but they will print faster.

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