Scanned PDFs on Kobo
Yes, Kobo eReaders open PDFs. A scanned one shows faint text inside wide margins, and you end up zooming and panning every page. Fixing the file once stops that.
Key takeaways
- Kobo eReaders and Kobo Desktop list PDF as supported. The Kobo Books app lists PDF on iOS but not on Android.
- Kobo's help pages state no PDF file size limit, so size matters less than on Kindle. Readability is the real problem.
- On a Kobo you can zoom with a slider or a pinch and pan around a page, but a zoomed page has to be panned before you can turn it.
- Cropping the margins once for the whole book makes the text bigger at the normal, unzoomed view.
- Copy the cleaned PDF over USB. It appears under My Books on that eReader only.
Where Kobo stands on PDFs
Kobo’s own format list is short and clear:
| Where you read | PDF? |
|---|---|
| Kobo eReader | Yes, as a book or a document |
| Kobo Desktop | Yes |
| Kobo Books app on iOS | Yes |
| Kobo Books app on Android | Not listed |
None of Kobo’s pages we checked gives a PDF size limit. That puts Kobo in a different spot from Kindle, where a file over 50 MB won’t go by email. On a Kobo, a big grey scan will usually copy across; it just reads badly.
Why a scan reads badly on a Kobo
The Kobo treats each page of a PDF as a fixed picture and fits it to the screen. It can’t enlarge the type, because a scan has no type to enlarge, only an image of paper with print on it.
That leaves you with Kobo’s PDF controls. According to Kobo’s PDF help:
- Zoom with the slider in the Reading Menu’s navigation panel, or by pinching.
- Pan by dragging once you’ve zoomed.
- Turn pages by tapping or swiping the sides, but only when the page isn’t zoomed. Zoomed in, you pan to the edge of the page first.
- Rotate the page 90 degrees from the same navigation panel.
Zoom works, but on a scanned book you zoom, pan across, pan down, pan across, and only then turn the page. Do that for 300 pages and most people give up by chapter two.
Fix the file, not the reading
The better route is to make the unzoomed page readable, so you never open the zoom slider at all. Three changes do most of it:
- Crop the margins. Everything outside the printed text, including the scanner’s dark edge and the spine shadow, comes off every page. The page that’s left is mostly words, so the words get the screen.
- Whiten the paper. Grey and yellow paper becomes white and the print becomes solid black, which is what e-ink shows best.
- Add a text layer. OCR puts hidden text under each page. Kobo’s PDF help doesn’t cover search or highlights in PDFs, and we haven’t tested them on a Kobo, but the text is there for your computer and any reader app that uses it.
Step by step
- Upload the scanned book to FixMyScan. PDF or DjVu, up to 1,000 pages.
- Draw the crop once. 50 pages are stacked over each other, so you can see where the text sits across the whole book before you draw.
- Leave the rest to the clean-up. Text pages go black on white, pages with pictures stay greyscale, crooked pages are straightened, and open-book scans are cut into single pages.
- Download the PDF. Same page order, same page numbers.
- Connect your Kobo to your computer. Turn it on, plug in the USB cable, and tap Connect when the “Computer detected” window appears.
- Drag the PDF onto the KOBOeReader drive. Eject the drive, unplug, and wait for “Importing content”. The book is in My Books.
Kobo notes that a file added this way shows only on the eReader you copied it to, not on your other Kobo devices or apps.
When the PDF still won’t open
Best suited for: books you own as plain PDFs or DjVu files, with no DRM.
- An ACSM file is a licence, not a book. Kobo says Adobe DRM books need Adobe Digital Editions, and that it works with Kobo eReaders but not the Kobo app.
- A DjVu file isn’t in Kobo’s format list. FixMyScan takes DjVu in and gives you a PDF back. See DjVu to readable PDF.
- A USB hub may not see the eReader. Kobo suggests plugging straight into the computer.
What this won’t do
You still read a PDF, so you can’t change the font. If you’d rather have a reflowing EPUB, scanned PDF or EPUB explains what a scanned book loses on the way. FixMyScan doesn’t remove DRM and doesn’t read handwriting.
FixMyScan is not affiliated with Kobo.
Questions
Can you download a PDF on a Kobo?
Yes. Kobo lists PDF as a supported format for its eReaders and for Kobo Desktop. You can copy one over USB, or load it from Google Drive or Dropbox, which Kobo's help also mentions.
Is PDF or EPUB better for Kobo?
For a book that began as text, EPUB, because you can change the font size. For a scanned book, a cleaned PDF, because turning a scan into EPUB means rebuilding every page from OCR, with errors, lost footnotes and lost page numbers.
How do I zoom a PDF on a Kobo?
Tap the middle of the screen to open the Reading Menu, tap the navigation icon, and drag the slider. You can also pinch the part you want bigger, then drag to move around.
How do I rotate a PDF on my Kobo?
Open the Reading Menu, tap the navigation icon, then the rotate icon. The page turns 90 degrees. Tap it again to go back.
Can I read PDFs in the Kobo app on Android?
Kobo's format list includes PDF for the iOS Kobo Books app and leaves it out for Android.
Why won't my PDF open on my Kobo?
If it came as an ACSM file, it has Adobe DRM and needs Adobe Digital Editions to reach the eReader. Kobo says the USB drag-and-drop method doesn't work with DRM-protected files.
Is there a file size limit for PDFs on Kobo?
Kobo's format and USB help pages don't state one. A smaller file is still easier to copy and to page through.
Is FixMyScan made by Kobo?
No. FixMyScan is not affiliated with Kobo or Rakuten Kobo.