# What is a PDF text layer?

Source: https://epubcc.com/glossary/text-layer/ (updated 2026-11-04)

The text layer of a PDF is the actual character data (which glyph, in which font, at which position) behind what you see on the page. You can select and search text only when it exists.

## Why it matters when you convert a PDF to EPUB

EpubCC converts from the text layer: it reads characters and their positions, then rebuilds words, lines, paragraphs and chapters. A page that is only an image has no text layer, and needs OCR first. A text layer can also be wrong (missing spaces, garbled characters) when fonts lack a ToUnicode map.

How EpubCC handles it: PDFium reads each glyph with its box, baseline, font size and weight, and the engine builds words, lines and paragraphs from those positions. A page with no text, only a full-page image, is counted and reported as a scanned page in the quality report instead of being dropped in silence.

**How do I know if my PDF has a text layer?** Try to select a sentence or search for a word in a PDF viewer. If nothing can be selected, the page is an image and has no text layer.