Text Layer
What a text layer is, how it gets into a document, and why it determines whether your PDF is truly searchable.
A text layer is the machine-readable text stored in a PDF page, separate from how the page looks. When a viewer searches, selects or copies text, it reads the text layer, not the pixels. A page without a text layer is only a picture, even if it shows words.
In PDFs exported from a word processor or browser, the visible text and the text layer are the same objects. In scanned pages and screenshots, the visible content is an image, and OCR adds a separate invisible text layer on top. The PDF specification provides a text rendering mode that neither fills nor strokes the glyphs, so this text is present but not drawn.
Text layer vs visible text
| Visible text | Text layer | |
|---|---|---|
| What the reader sees | Yes | Only if drawn |
| Searchable | Only through the text layer | Yes |
| Source | Fonts or image pixels | Document text or OCR |
A page can look perfect and have no text layer, or have a text layer full of OCR errors behind a clean image.
Where text layers matter
- Searching archives of scanned or captured documents.
- Copying quotes, numbers and code from PDFs.
- Screen readers and indexing tools.
- Translation and summarization tools that read PDF text.
How a text layer is created
- From the source: exporting from an app writes real text objects.
- From OCR: software recognizes characters in the image, then writes them as invisible text at matching positions and sizes.
- From editing: some PDF editors add or correct text manually.
OCR quality depends on resolution, contrast, font and language. A 2x screenshot usually gives better results than a heavily compressed 1x image.
Common mistakes with text layers
- Checking a PDF visually and assuming it is searchable.
- Running OCR twice, which can stack duplicate text layers.
- Flattening or printing a PDF to an image, which removes the text layer.
- Trusting OCR text without proofreading numbers and names.
Turning pages into a PDF?
Temposhot adds an OCR text layer when it exports a capture session as PDF. For existing images, use the Screenshot to Searchable PDF. See save screenshots as PDF on Mac.
Common questions
How do I check for a text layer?
Search for a visible word or try to select text. If neither works, there is no text layer.
Can I edit a text layer?
Yes, in PDF editors that support OCR correction or text editing.
Sources
Related resources
- Screenshot to searchable PDF: add a text layer in the browser.
- Extract text from image: read text from a single image.
- Export formats: searchable PDF export.
Taking the same screenshots again and again?
Temposhot captures a screen, window or area on a timer and exports the set as a PDF, images, ZIP or MP4. The free browser tools fix single images.
Related resources
Related terms
- Searchable PDFWhat makes a PDF searchable, how to tell if yours is, and common mistakes when working with image-only PDFs.
- OCRWhat OCR is, how it works, where it's used, and common mistakes to avoid when making screenshots and scans searchable.
- Image-Only PDFWhat an image-only PDF is, why it limits search and accessibility, and how to make it searchable.
- Tagged PDFWhat a tagged PDF is, why it matters for accessibility, and how it differs from a searchable PDF.