Preview.app increases PDF file size after deleting pages

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Level 1

9 points

Preview.app increases PDF file size after deleting pages

Hello, I'm experiencing odd behavior with Preview.app and PDFs.

If I open a PDF with Preview, delete a page, then save the file, the file size increases anywhere form 2x to 20x. This happens both with PDFs that only contain text and PDFs that contain text and graphics. It is very frustrating because I start with a file that is 150KB, remove some pages and end up with a 10MB monster that I can't email to people.

Any help is appreciated. I can post a link to a test PDF for people to try to replicate with if it would be useful.

mac pro, Mac OS X (10.5.2)

Posted on Apr 9, 2008 7:44 AM

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Answer 1

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fixed point Author

Level 1

9 points

Apr 10, 2008 5:25 PM in response to fixed point

I experimented a little and the problem seems to be with the PDFKit that is part of Quartz. I wrote a program using the framework that just opens a pdf, deletes the first page, then saves it. Same behavior: around 10x increase in file size.

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Answer 2

Apr 10, 2008 7:36 PM in response to fixed point

I tried a 14 page, 320KB file. Deleting the first page reduced it to 296KB. Can you post a link to the file?

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Answer 3

fixed point Author

Level 1

9 points

Apr 10, 2008 7:45 PM in response to Malcolm Rayfield

Here is a 32KB file that increases to 60KB after deleting the fourth page.

http://jahana.com/test.pdf

I probably shouldn't post one of the files that shows a dramatic increase because of copyright concerns.

Thanks!

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Answer 4

Apr 10, 2008 7:56 PM in response to fixed point

I get the same result (60KB) here with your file. My file shrinks when I delete page 1 or 13 (out of 14). How was yours generated? Mine was from OSX's Print to PDF.

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Answer 5

fixed point Author

Level 1

9 points

Apr 10, 2008 8:02 PM in response to Malcolm Rayfield

I generated the file with pdftex. I'm guessing that there must be different ways to encode a PDF and when Preview gets something with an encoding other than that provided by PDFKit, it rewrites the file how it likes. In my case this is increasing the file sizes. I tried finding docs about PDFKit on the Apple developer site, but couldn't find any details about ways of encoding a PDF.

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