PDF and text
What is Text layer?
Also called searchable PDF or OCR layer.
A text layer is the real, selectable text inside a PDF. Without one, a PDF is only pictures of pages and its words can’t be searched or copied.
How it works
PDFs created from documents contain positioned text: the file knows each word, its font and where it sits. That text layer is what lets you search, select, copy, and have a screen reader read the page aloud.
Scanners and phone scanning apps produce images of pages instead. They look like documents but contain no characters at all. OCR can recognize the words and place an invisible text layer exactly behind the image, producing a “searchable PDF” that looks unchanged but behaves like a normal document.
Why the text layer matters for privacy
The text layer can also reveal information after it has been visually hidden. Covering text with a black box hides the image of the words but can leave the text layer untouched, which is why proper redaction removes both.
A practical example
Pressing Ctrl+F in a scanned contract finds nothing. After OCR adds an invisible text layer behind each page image, the same search highlights every match.
What to watch out for
An OCR text layer can contain recognition mistakes that aren’t visible, because you still see the original image. Copy important numbers from the page and check them.
Tools you can use
- PDF to Text · Copy the words out, in reading order
- Image to Text · Copy text out of screenshots, photos and scans
- Image to PDF · Turn photos and scans into one document
- PDF to JPG · Every page as an image, at the DPI you need
Go a little deeper
- How to make a scanned PDF searchable
- Why can’t I copy text from a PDF?
- How to convert a PDF to JPG on a phone
- How to copy text from a screenshot or image
Common questions
How can I tell if a PDF has a text layer?
Try to select a word or search for one. If you can highlight individual words, the text layer exists. If the whole page selects like a picture, it doesn’t.
Why can’t I copy text from my PDF?
Either the PDF is a scan with no text layer, or copying has been restricted by its security settings. OCR fixes the first; the second needs the owner’s permission.
Does converting a PDF to images remove the text?
Yes. The pages become pictures, so search, copying, links and screen reader access are lost. Keep the original if you need them.