# Can I use an offline pdf compressor for thesis scans?

**URL:** <https://pdfbookslib.com/discussions/t/can-i-use-an-offline-pdf-compressor-for-thesis-scans/127>\
**Category:** Digitizing Old Books\
**Tags:** epub\
**Created:** [November 10, 2026, 10:57pm UTC](https://pdfbookslib.com/discussions/t/can-i-use-an-offline-pdf-compressor-for-thesis-scans/127 "2026-11-10T22:57:10Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![beer](https://pdfbookslib.com/discussions/letter_avatar_proxy/v4/letter/b/f04885/32.png) [@beer](https://pdfbookslib.com/discussions/u/beer)\
**Post date:** [November 10, 2026, 10:57pm UTC](https://pdfbookslib.com/discussions/t/can-i-use-an-offline-pdf-compressor-for-thesis-scans/127/1 "2026-11-10T22:57:10Z")

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My master’s thesis appendix has about fifty scanned pages and the file is way over the university portal’s 25 MB limit. Is there a reliable offline way to compress these PDFs without uploading them anywhere?

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**Author:** ![reid21](https://pdfbookslib.com/discussions/user_avatar/pdfbookslib.com/reid21/32/22_2.png) [@reid21](https://pdfbookslib.com/discussions/u/reid21)\
**Post date:** [November 10, 2026, 10:57pm UTC](https://pdfbookslib.com/discussions/t/can-i-use-an-offline-pdf-compressor-for-thesis-scans/127/2 "2026-11-10T22:57:16Z")

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Honestly the easiest offline route is stuff already on your machine. On a Mac, open it in Preview and export with the reduce file size filter. On Windows, try printing it to PDF at a lower DPI like 150, which usually shrinks scans a ton.

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**Author:** ![finlay.wilson](https://pdfbookslib.com/discussions/user_avatar/pdfbookslib.com/finlay.wilson/32/23_2.png) [@finlay.wilson](https://pdfbookslib.com/discussions/u/finlay.wilson)\
**Post date:** [November 12, 2026, 4:36am UTC](https://pdfbookslib.com/discussions/t/can-i-use-an-offline-pdf-compressor-for-thesis-scans/127/3 "2026-11-12T04:36:52Z")

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I had this exact problem with bulky patient scans at our clinic. I struggled to find a decent offline programme on my work PC, so I used PDFcap instead. On [pdfcap.com](http://pdfcap.com), you just drop the document in and hit compress. It got my file size right down without making the pages unreadable.

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**Author:** ![sarcastic\_sea](https://pdfbookslib.com/discussions/user_avatar/pdfbookslib.com/sarcastic_sea/32/33_2.png) [@sarcastic\_sea](https://pdfbookslib.com/discussions/u/sarcastic_sea)\
**Post date:** [November 13, 2026, 11:21am UTC](https://pdfbookslib.com/discussions/t/can-i-use-an-offline-pdf-compressor-for-thesis-scans/127/4 "2026-11-13T11:21:54Z")

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If you have a Mac, open the file in Preview and export it using the reduce file size filter. On Windows, just paste your scans into Word, use the compress pictures option, and save as a PDF. Avoid dropping the resolution below 150 DPI or your text will become an unrecognisable blur. I learned that the hard way when emailing my market price lists.