How to Split Scanned Book Pages into Single Pages

If you've scanned a book on a flatbed, you know the routine. Open it face down, press the spine flat, scan, turn two pages, scan again. It's the fastest way through a book, and it leaves you with a PDF where every page holds two book pages side by side.

On a big monitor that's fine. On a phone or an e-reader it's miserable: the text is tiny, zooming in means scrolling sideways on every page, and printing gives you two miniature pages per sheet. What you actually want is one book page per PDF page, in the right order.

Why "Split PDF" won't fix it

Most PDF tools use "split" to mean breaking a document into several files, say pages 1 to 20 in one file and the rest in another. The pages themselves are never touched. For a book scan you need to cut through the middle of each page and keep both halves. That's a different job, and it's the one Split PDF Pages in Half was built for.

Splitting the scan

1. Open the scan in the tool. The file is opened in your browser and isn't uploaded anywhere, which is worth knowing if the book is still under copyright or the scan is something personal.
2. Choose Vertical. A book lying open needs a cut down the middle. Horizontal is for layouts stacked top and bottom, like some two-up handouts.
3. Check the cut line. It starts at 50%. Books rarely sit exactly in the middle of the scanner glass, so look at a few pages in the preview and drag the line into the gutter if it clips any text.
4. Pick which pages to split. More on this below, because covers catch most people out.
5. Download. Each spread becomes two pages, left half first.

Covers and other single pages

The front and back covers are usually scanned on their own, so they're already single pages. Split them and you end up with half a cover and a strip of scanner lid. Instead of "All pages", choose custom pages and enter only the spreads, for example 2-149. Anything you leave out is copied into the new file unchanged, in its original place.

When the book moved halfway through

The cut position is the same for every page you split. If the book slid a little partway through the session (it happens once your hand gets tired of holding the spine), the gutter moves and a single cut line won't suit every page.

The simplest fix is two passes. Split the first stretch of spreads with the line where it suits them, then open the result and split the remaining spreads with the line moved. Just remember the page numbers change after the first pass: 79 spreads become 158 pages, so everything after them shifts along.

Books that read right to left

The tool always puts the left half first. That's correct for English and most European languages, but for Arabic, Hebrew or Japanese books each pair will come out the wrong way round. You can put them in order afterwards with Rearrange PDF Pages, although on a long book that's a lot of dragging.

Tidying up

Scans nearly always have a dark edge from the scanner lid, and after the cut the outer margins are often uneven. Crop PDF lets you draw the area to keep and applies it to every page, which makes a real difference on a small screen. Use a page with typical margins to draw the box, not the title page.

Scanned books are also large files, because every page is a picture. Compress PDF can shrink one before you copy it to a tablet. How much you save depends on how the scan was made, so check a page or two for readability before deleting the original.

Getting the text out

A scan is just images of pages, so you can't search it or copy a quote from it. PDF OCR reads the text off the pages and gives you a plain text file you can search and copy from. To be clear, it doesn't turn the PDF itself into a searchable PDF; you keep the scan and the text as two separate files.

Accuracy depends mostly on the scan. Sharp, straight pages come out well. Text that curves into the spine, faint print and handwriting come out worse, so read through anything you plan to quote.