PDF compression issues

[Aprameya5ED9]

I'm trying to compress a pdf that's ~900 pages, mostly text (it's a textbook) and 500MB - this is obviously too big. But when I go to adobe acrobat and try to compress, it gives me an error saying that the PDF is already compressed. I can't deal with such large file sizes on my school computer, and they would defeat the purpose of even having the textbook online. Any help would be appreciated.

[Bernd Alheit]

Try the forum for Adobe Acrobat.

[Meenakshi Negi]

Hi Aprameya5ED9,

Thank you for reaching out. 

Please let us know if the PDF was created and compressed before. Generally, the message appears only when the file is compressed to its maximum limit. 

Did you create the PDF or receive it from some other source? Would you mind sharing the PDF with us?

Also, check if you see a similar behavior with other files.  

Share the Acrobat and PDF version numbers.

Thanks,

Meenakshi

[Aprameya5ED9]

I don't know if the PDF was compressed before. I got it from this extension which probably just puts together images of every single page. I can't upload files bigger than 47MB here, so here is a link you can download the PDF from. I used online adobe acrobat signed into my account to try to compress it. Thanks for your help.

[Test Screen Name]

This appears to be an app to breach copyright ("Some books can only be read online by borrowing for a limited period. This extension can download these books for later reading."). We can't help with such things.

[try67]

If all the pages in this file are scanned then this is a normal file size, as it means about 1.8MB per image, which is really not a lot, plus the PDF file overhead data itself...