Scanned documents
A scan is a photograph of each page. It looks right, but on its own it has no text in it, only a picture of text. That decides whether your flipbook has a transcript, search inside the document, text a screen reader can read aloud, and anything for search engines to index.
Who adds the text
Section titled “Who adds the text”On a paid plan, we do. When a page has no text, we run OCR (optical character recognition) to read the words off the image: up to 150 pages per document. You don’t need to do anything.
On the Free plan, there’s no OCR, so a scan stays image-only unless it already has text when you upload it. The good news is that several scanning apps add the text themselves, for free.
Scanning with your phone
Section titled “Scanning with your phone”Adobe Scan (iPhone and Android) runs text recognition on the saved PDF by default, so the file it gives you already contains real text. The setting is called Run Text Recognition (iPhone) or Run text recognition on saved PDF (Android). The free version limits it by page count, and Adobe’s own pages give different figures for iPhone and Android, so check a long scan before relying on it.
iPhone and iPad: the Notes app can scan straight to a PDF (in a note, tap the attachment button → Scan Documents), and so can Preview on recent versions of iOS. Apple doesn’t say whether these PDFs include searchable text, so check the result (below) before uploading on Free.
Scanning an existing PDF
Section titled “Scanning an existing PDF”If you already have an image-only PDF, Adobe Acrobat can add the text layer. See Adobe Acrobat.
How to tell if your scan has text
Section titled “How to tell if your scan has text”Open the PDF and try to select a sentence with your cursor. If the words highlight, there’s text. If you can only drag a box over the page, it’s an image.
Getting a good scan
Section titled “Getting a good scan”- Flat, even light, no shadows. OCR reads a clean page far better than a curled, shadowed one.
- Straight on. Scanning apps correct perspective, but a squarer photo gives sharper text.
- One page per page. Scan a booklet one page at a time rather than as open spreads; the reader pairs pages up itself. See Spreads vs single pages.
- Check the size. Scans are large, because every page is a photo. Most apps have a quality or size setting; see Getting a PDF under 50 MB.