Image-only PDF – Failed
Acrobat’s “Image-only PDF – Failed” means pages are pictures of text, usually scans. Why OCR alone isn’t enough, and how to make a scanned PDF accessible.
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This message comes from Adobe Acrobat's Accessibility Checker.
Image-only PDF – Failed is a result from the Accessibility Checker in Adobe Acrobat Pro, in its Document category. It means the document appears to be pictures of pages, usually a scan or a photo, with no real text behind them. Adobe's help explains that a document that seems to contain text but has no fonts may be an image-only PDF. A screen reader finds nothing to read in it, and people can't search, copy or cleanly enlarge the text.
What this means
A scanned page is a photograph of a page. You can see words, but the file holds only pixels. To a computer, there's no text at all.
Making a scan accessible takes three stages, and the first is the only one most people know about:
- OCR (optical character recognition): software recognizes the words in the image and adds a hidden layer of real text.
- Correction: OCR makes mistakes, especially with faint or skewed scans, small print, tables, stamps, signatures and handwriting. Someone has to check the result against the original.
- Tagging: the recognized text still needs structure, such as headings, lists, tables, figures and reading order, like any other PDF.
OCR alone makes a scan searchable. It doesn't make it accessible.
Watch for mixed files, too. A report with one scanned signature page, or an agenda packet with scanned attachments, has unreadable pages even if most of the file is fine, so check every page, not just the first few.
Why it matters
Screen reader users hear nothing, or an empty document. People with low vision can't reflow the text or enlarge it without blur. People with dyslexia can't use text-to-speech or change the font. Even search engines and your own site search can't find what's in the file. This affects WCAG 2.1 success criteria 1.1.1 Non-text Content and 1.4.5 Images of Text.
How to fix it in Acrobat Pro
- Look for the original digital file first. If the scan was printed from a Word or InDesign file, export a tagged PDF from that instead. It's almost always better than OCR.
- If the scan is all you have, run text recognition. In the Accessibility Checker panel, right-click Image-only PDF and choose Fix, or use Acrobat's Scan & OCR tool to recognize the text in the file.
- Set the recognition language to match the document, especially for Spanish or bilingual documents.
- Check the recognized text. Copy a page into a plain text editor, or listen with a screen reader, and correct the errors you find against the original.
- Tag the document with Acrobat's autotag (Automatically tag PDF, or Autotag Document in older versions), then work through the usual fixes: headings, reading order, alt text for photos and signatures, and tables.
- Run the accessibility check again.
When OCR isn't good enough
Handwriting, poor copies of copies, and complex forms often come out badly from OCR. For documents people rely on, such as notices, permits and legal records, have a person check the text against the original, or retype the document.
Fix it in the source file
The best scanned PDF is one you didn't have to scan:
- New documents: publish the digital original as a tagged PDF rather than printing and scanning it.
- Signatures: if a signed page must be included, put the signed version alongside an accessible digital version of the same text, rather than scanning the whole document.
- When you must scan: scan straight and flat, at a resolution of about 300 dpi, in black and white or grayscale for text pages. OCR accuracy depends heavily on scan quality.
Fix it automatically with Includoc
Includoc fixes this automatically. We run OCR in English and Spanish, tag the result with headings, paragraphs, tables, figures and reading order, and show you the OCR confidence for each page.
Correction still needs a person. Pages where recognition confidence is low are listed for you to check against the original, and the human-verified tier can check them for you. We can't reliably recognize handwriting, so handwritten pages need a person to transcribe them.
Upload your PDF to fix this automatically
Free check in seconds. Files are deleted within 24 hours.
Standards
| Standard or tool | Reference |
|---|---|
| WCAG 2.1 | |
| PDF/UA-1 (ISO 14289-1) | Clause 7.1 |
| Matterhorn Protocol | Checkpoint 08-002 |
| Acrobat rule | Image-only PDF |
| Standard or tool | Reference |
|---|---|
| WCAG 2.1 | |
| Matterhorn Protocol | Checkpoint 08-001 |
Related errors
- Character encoding – Failed: text that exists in the file but can't be read as real characters.
- Content is tagged or artifacted: once OCR adds text, it still needs tags.
For a complete walkthrough, read Scanned PDFs and OCR, or check a PDF free to find pages with no real text.
Related
- Character encoding – Failed
Acrobat’s “Character encoding – Failed” means some text can’t be turned into real characters, so it reads as garbage. How to test it and how to fix it.
- Content is tagged or artifacted
PAC fails “Content is tagged or artifacted” when page content is neither tagged nor marked as decoration. What it means and how to fix it.
- Scanned PDFs and OCR: how to make an image-only PDF accessible
Image-only PDFs have no text for screen readers. Run OCR in Acrobat or OCRmyPDF, check the accuracy, tag the result, and know when to retype instead.