PDF4WCAG Accessibility Checker for PDF 2.0
Source: Dev.to
Overview
PDF 2.0 is the first core PDF standard developed entirely under ISO guidelines & processes. The standard was published in 2020 as ISO 32000‑2:2020, and industry adoption is beginning to grow. PDF 2.0 (ISO 32000‑2:2020) is an open, international standard designed to work across platforms and vendors.
Highlights
- Backwards compatible – aligned with common implementations & current user expectations for PDF 1.7.
- Rewritten Tagged PDF & Accessibility – significant enhancements for accessibility through a richer tagging structure and support for more complex content.
- Feature‑rich for all users & use cases – accompanied by updated subset standards such as PDF/A‑4 (archival) and PDF/UA‑2 (universal accessibility).
- Associated files – allow other files to be attached in appropriate structures (e.g., computer‑readable copies or alternative representations).
- MathML support – formal definition of MathML inclusion in the PDF structure tree, a crucial improvement for scientific publications.
Tagged PDF in PDF 2.0
In PDF 2.0, Tagged PDF is improved by:
- Fewer tags.
- Better descriptions of tags.
- Clear indication of where tags can/cannot be used.
- More flexibility (restrictions exist only where necessary).
The additional Technical Specification ISO/TS 32005:2023 defines the inclusion of PDF 1.7 structure elements into PDF 2.0 (link).
Accessibility of PDF 2.0 – governed by PDF/UA‑2 (2024)
Accessibility of PDF 2.0 documents is governed by the PDF/UA‑2 standard, published in March 2024. PDF/UA‑2 supersedes PDF/UA‑1 and addresses its shortcomings by building on the modern PDF 2.0 specification, providing more explicit requirements.
LaTeX support for PDF/UA‑2
The LaTeX Project now implements PDF/UA‑2 support for scientific publications, including correct tagging of mathematical formulas via MathML.
Key point: PDF/UA‑1 was not designed for mathematics, so “compliant” documents were often unusable for people with disabilities. PDF/UA‑2 handles math properly, making STEM documents truly accessible.
veraPDF – validation for PDF/UA‑2
VeraPDF has added support for PDF/UA‑2 validation, allowing users to check documents against the machine‑verifiable rules of the new standard. Validation is performed using XML‑based validation profiles that the veraPDF engine consumes at runtime.
PDF4WCAG – a friendly web interface
PDF4WCAG wraps veraPDF in a web interface with error preview and is free for non‑commercial use. It validates PDFs against PDF 2.0, PDF/UA‑1, PDF/UA‑2, and Well‑Tagged PDF profiles, presenting clear visual reports that anyone can understand.
It leverages the veraPDF validator to provide visual reports, making it easy to identify and resolve compliance issues without technical expertise. Free non‑commercial access brings professional validation tools to everyone.
To sum it up
- PDF/UA‑2 fixes long‑standing accessibility gaps—especially for mathematics.
- LaTeX now supports accessible math via MathML, enabling true STEM accessibility.
- veraPDF provides official, machine‑verifiable validation for PDF/UA‑2.
- PDF4WCAG makes these validations visual, simple, and accessible to everyone.
WCAG validation for PDF 2.0 documents
When performing WCAG validation, PDF4WCAG differentiates between PDF 2.0 and PDF 1.7 (or earlier) versions of PDF. The validation of PDF 2.0 documents is based on a newer PDF/UA‑2 substandard, while all earlier versions of PDF 1.7 use PDF/UA‑1 as a basis. See What is WCAG for PDF for more details on how WCAG validation is related to PDF/UA requirements.