MobileRead Forums - View Single Post - Best way to convert JPEG page images to PDF

HarryT · 08-21-2015, 04:04 AM

To follow up on this, the CBZ to PDF conversion worked beautifully for several books that were around 200 pages long (a CBZ file about 70MB in size). I then tried it for a book that was 450 pages long, and Calibre (32-bit Calibre running on a Windows 7 laptop with 4GB RAM) ran out of memory in the final PDF output stage of the conversion process.

Luckily my work laptop has 16GB RAM, so I installed 64-bit Calibre on that, and it converts the books with no problems

. The largest book I've so far tried it on has been 953 pages (a 168MB CBZ) and 64-bit Calibre converts it fine, creating a 322MB PDF. Pretty big, but "GoodReader" on my iPad displays it fine.

Does anyone have any tips for ways to shrink the size of the PDF? They are page scans, and completely unsuited for OCR. It's a hand-written book - basically the diary of an expedition to Egypt in the 1820s - and every page has little sketches of buildings, hieroglyphic inscriptions, etc, on it. I've attached one of the page scans to shows what a typical page looks like. As you can see, there's absolutely no way it could sensibly be OCR'd!. Can anyone think of a way to reduce the size of the PDF?

I should add that it's not particularly a problem that the PDF is 322MB in size; I have a 128GB iPad so I'm not short of storage space, but obviously smaller is better

.

Many thanks,

08-21-2015, 04:04 AM	#11
HarryT eBook Enthusiast Posts: 85,557 Karma: 93980341 Join Date: Nov 2006 Location: UK Device: Kindle Oasis 2, iPad Pro 10.5", iPhone 6	To follow up on this, the CBZ to PDF conversion worked beautifully for several books that were around 200 pages long (a CBZ file about 70MB in size). I then tried it for a book that was 450 pages long, and Calibre (32-bit Calibre running on a Windows 7 laptop with 4GB RAM) ran out of memory in the final PDF output stage of the conversion process. Luckily my work laptop has 16GB RAM, so I installed 64-bit Calibre on that, and it converts the books with no problems . The largest book I've so far tried it on has been 953 pages (a 168MB CBZ) and 64-bit Calibre converts it fine, creating a 322MB PDF. Pretty big, but "GoodReader" on my iPad displays it fine. Does anyone have any tips for ways to shrink the size of the PDF? They are page scans, and completely unsuited for OCR. It's a hand-written book - basically the diary of an expedition to Egypt in the 1820s - and every page has little sketches of buildings, hieroglyphic inscriptions, etc, on it. I've attached one of the page scans to shows what a typical page looks like. As you can see, there's absolutely no way it could sensibly be OCR'd!. Can anyone think of a way to reduce the size of the PDF? I should add that it's not particularly a problem that the PDF is 322MB in size; I have a 128GB iPad so I'm not short of storage space, but obviously smaller is better . Many thanks, Attached Thumbnails Last edited by HarryT; 08-21-2015 at 04:18 AM.