Scanned PDFs, text layers and OCR

2026-10-30

You open a scanned letter or a photographed receipt in PDF to Text and the answer is No selectable text found in this PDF. Nothing is broken. The file simply contains no text for the tool to read. To see why, it helps to know the difference between a text layer, an image-only scan and OCR.

Three kinds of PDF page

A page with a text layer. The text was typed, exported from a word processor or saved from a browser. The PDF stores the actual characters, so you can select them, search them and copy them.

An image-only page. A scanner or a phone camera took a picture of paper and put that picture into a PDF. To you it looks like text; to the computer it is a grid of coloured dots. There are no characters to select.

A scanned page that already went through OCR. OCR, short for optical character recognition, is software that looks at the picture, recognises the letters and adds an invisible text layer behind the image. Many scanners and scanning programs can do this when the document is saved. The page still looks like a scan, but now it also carries text.

What PDF to Text does with each

PDF to Text reads text layers only. It does not do OCR, and it does not read text inside pictures. So:

• A typed or exported PDF works as usual.
• An image-only scan has nothing to extract. If every page is an image, you see the message above, and Copy all and Download TXT stay off. If only some pages are images, the note at the top names them, for example “pages 3–5”, and each of those pages says it is an image and may be scanned.
• A scan that was already processed with OCR is fine: its hidden text layer is read like any other. How good that text is depends on how well the recognition worked when the file was made.

How to tell which one you have

1. Open the PDF in any viewer and try to select a sentence.
2. If individual words highlight, there is a text layer, and PDF to Text can read it.
3. If the whole page highlights as one block, or nothing highlights at all, the page is an image.

Getting text out of an image-only scan

For a page that is only a picture, text has to be created before it can be extracted, and that is the job of OCR software, a different kind of tool. Some scanners offer a “searchable PDF” option when saving, which runs recognition at that point. Once a scan has a text layer, you can open it here, read through the pages and copy or save the text.

If what you actually need from the PDF are the pictures themselves, a separate tool, Extract Images, is meant for that.