The problem this solves
Many PDFs contain fonts with missing Unicode mappings – glyphs that display correctly on screen but carry no machine-readable character data. Screen readers cannot interpret these characters, which causes documents to fail PDF/UA (ISO 14289) and WCAG 2.1 audits.
Fixing this manually, glyph by glyph, is impractical at any scale.
What Font Fix PDFix does
Font Fix is a free locally-executed PDFix Desktop action that uses OCR to detect glyphs with missing Unicode values and automatically assign the correct mappings. It processes the entire document without sending any data to external services. The result is a PDF where every character is machine-readable, accessible to screen readers, and compliant with PDF/UA requirements.
It runs as a Docker-based action and integrates directly into PDFix Desktop’s batch processing pipeline.
Key capabilities:
- Detects missing Unicode mappings across all font types in a PDF
- Uses OCR to recover the correct character value for each unmapped glyph
- Runs entirely on your local machine — no cloud connection, no data transfer
- Supports batch processing of multiple PDFs in a single automated workflow
Action
| Free · Local | Font Fix (PDFix) | Automatically detects and repairs missing Unicode mappings in PDF fonts using OCR recognition technology. |
Frequently Asked Questions
What is a missing Unicode mapping in a PDF?
A Unicode mapping tells software – including screen readers and search engines – which character a glyph represents. When a PDF font lacks these mappings, the text is visually present but machine-unreadable. This is one of the most common causes of PDF/UA and WCAG accessibility failures.
Does Font Fix work on scanned PDFs?
Font Fix is designed for PDFs with embedded fonts that have incomplete Unicode tables. For PDFs that are purely image-based scans with no text layer at all, use the OCR Tesseract action first to generate a text layer, then apply Font Fix if needed.
Which PDF/UA checkpoint does this address?
Font Fix targets PDF/UA-1 (ISO 14289-1) requirement 7.21.3, which requires that all font characters used in a document have Unicode mappings. It also supports WCAG 2.1 Success Criterion 1.4.5 compliance.
Is this action free to use?
Yes. Font Fix (PDFix) is 100% free for all PDFix Desktop users with no additional license or payment required.
Does it require an internet connection?
No. Font Fix runs entirely on your local machine using Docker. No document data is sent to any external server or third-party service.
