https://txtfetch.com/glossary/text-layer/
PDF text layer
The grid of character codes and positions drawn into a PDF page, separate from what the page image shows. No text layer means nothing to extract.
definition
A PDF text layer is the set of font-encoded character-position operators drawn into a PDF page. This data lets you select, search, and extract text on the page, separate from how the page looks.
Also called: text layer, invisible text layer, PDF text layer vs. image
in-plain-terms
Every PDF page renders as pixels on screen. But whether those pixels came with actual characters behind them is a separate question. A born-digital PDF is one made by a word processor, a report generator, or a print-to-PDF step. It writes both the glyph shapes to draw and the character codes and positions that let a reader select and copy text. A scanned page saved as a PDF has only the picture. It has no text layer to read, because none was ever written.
This is why an empty extraction from a PDF usually isn't a bug. If you can't select a word in your PDF viewer, no extraction library can read one either, because there's genuinely nothing there. OCR is the fix when a page has none. See the ocr and searchable-pdf entries below.
example
>>> extracted_text
''A scanned page has no text layer. Any attempt to extract text from it returns nothing. That is the correct answer, not a parsing failure.
why-it-matters
- Some documents have a text layer on some pages but not others, like a digital cover sheet ahead of a scanned body. This case fools a whole-document blank check, because the document isn't empty overall.
- OCR only helps pages that don't already have a text layer. Running it over a page that already has real, selectable text just adds recognition errors where there were none.
how-to-check
- Try selecting text on the page in any PDF viewer. No highlight means no text layer on that page.
- Run a file through the PDF text-layer checker. It reports per page instead of per document. Check a PDF's text layer
related-terms
faq
- How do I know if a PDF has a text layer?
- Try selecting text on the page in any PDF viewer. If nothing highlights, there's no text layer to select, and no extraction library will find one either. The PDF text-layer checker automates this per page rather than per document.
- Why did my mixed PDF come back with some text but not all of it?
- A digital cover page ahead of a scanned body means the document isn't blank overall. So a whole-document check doesn't flag the scanned pages behind it as missing their own text layer. Check per page, not per document.
related-reading
See the term in real output.
Drop a file into the free reader and watch it happen.
Open the file reader →