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Old 06-21-2020, 05:57 PM   #8
Marinolino
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Join Date: Feb 2018
Device: Kobo Aura-One (using KOReader app), Boox Note-3, iPad(s)
Quote:
Originally Posted by Bookchin View Post
...

I'd like to reduce the file size while retaining high quality. I don't need a 50% size reduction, but 20-30% would be nice.
You should experiment with 300 and 600 dpi downsampling, and see the quality and the conversion speed, using e.g. 30-40 sample pages from your 500 or 1000 pdf scan.

For my text books (without many pictures and graphics therein) Clearscan mode applied to 300 dpi input files is usually good enough for me, and it results in 2-4 MB pdf file per 100 pages i.e. 10-20 MB pdf for 500 page book.

I'd quickly crop double-paged scans and trim its margins using Briss or k2pdopt beforehand.

In the future, if you want even smaller and neater pdfs, you can use Scantailor before applying Clearscan OCR , to automatically crop double-paged scans, deskew and despeckle scanned images, trim the margins, remove the background etc.

https://www.youtube.com/watch?v=Edfs2_YJhx4

https://www.youtube.com/watch?v=dHZmTYTVL44

Last edited by Marinolino; 06-22-2020 at 12:56 PM.
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