Matterhorn Protocol

The Matterhorn Protocol is the PDF Association's testing model for PDF/UA. It turns the formal standard into 31 checkpoints and 136 failure conditions that tools and human auditors can apply the same way.

It is not a list of automated checks alone. Matterhorn itself marks 87 failure conditions as machine-testable and 47 as usually needing human judgment. A few checkpoints exist because PDF/UA mentions constructs that ordinary document PDFs rarely use (for example flickering content or sound) - they are still part of the shared checklist.

Silktide's automated PDF checks and AI review are organised against Matterhorn. When the Check tab reports an automated failure, it is naming a Matterhorn condition that the document has not met - for example a missing document title, an image without a text alternative, or a table without a proper structure.

Learn more

• The Matterhorn Protocol - PDF Association resource
• PDF/UA
• PDF standards coverage