Accessibility Standards & Evidence

Last updated: January 2026. Reflects current PDF/UA and Matterhorn Protocol guidance.

This document serves as a canonical reference for how Inkable Docs evaluates accessibility, the specific standards it adheres to, and the evidence generated for procurement and compliance audits.

What standards are evaluated

Inkable Docs evaluates documents against PDF/UA (ISO 14289-1) using the Matterhorn Protocol, a standardized PDF/UA conformance testing model maintained by the PDF Association.

PDF/UA (ISO 14289-1)

PDF/UA (Universal Accessibility) is the definitive international standard for accessible PDF technology. Unlike general accessibility guidelines, PDF/UA provides specific technical requirements for the software and the document structure. It requires:

  • Logical tagging of all content (headings, paragraphs, lists, tables).
  • A validated reading order that follows the visual flow.
  • Alternative text for all non-text elements.
  • Properly declared document metadata (Title, Language).
  • Artifacting of purely decorative elements to hide them from assistive technology.

Matterhorn Protocol

The Matterhorn Protocol is a testing model developed by the PDF Association to specify how to evaluate a document for PDF/UA conformance. It consists of 31 checkpoints and 136 failure conditions. Inkable Docs maps its internal rules directly to these failure conditions to provide objective pass/fail results.

WCAG

While WCAG (Web Content Accessibility Guidelines) is primarily designed for web content, its four principles—Perceivable, Operable, Understandable, Robust—are foundational to document accessibility. Inkable Docs ensures that document semantics (like link descriptive text and color contrast) align with WCAG 2.1 Level AA requirements.

Legal & procurement frameworks

Inkable Docs evidence is designed to satisfy the technical documentation requirements for common accessibility laws and procurement standards:

Section 508 (US)

Requires federal agencies and institutions receiving federal funding to make their electronic documents accessible.

EN 301 549 (EU)

The European standard for digital accessibility, which harmonizes with WCAG and PDF/UA for public sector documents.

ADA (Title II/III)

Applied to higher education and public accommodations to ensure equal access to digital materials.

What checks are automated

Inkable Docs automates the technical validation of document structure to ensure machine-readable compliance:

Structure & Semantics

  • Heading level hierarchy (H1-H6)
  • List nesting and item identification
  • Table header (TH) and data cell (TD) mapping
  • Paragraph and span tagging

Metadata & Logic

  • Document title and primary language
  • Reading order serialization
  • Alternative text presence for non-decorative media
  • Link descriptive text and URI validity

What requires human judgment

Automation cannot determine intent. Inkable Docs prompts users to verify contextual accessibility markers that require human expertise:

  • Contextual Alt Text Quality: While AI provides descriptions, a human must confirm the text conveys the specific educational or informational intent of the image in context.
  • Decorative vs. Meaningful: Decisions on whether an image is purely aesthetic (decorative) or requires a description must be confirmed by the author.
  • Semantic Intent: Ensuring that the choice of a heading or list accurately reflects the logical organization of the content.

Scope & responsibility

To maintain reference integrity, we define the boundaries of our automated assessment:

  • Interactive Forms: Inkable Docs focuses on document structure and reading order. Complex interactive PDF forms with custom scripting are outside current assessment scope.
  • External Media: Accessibility of content hosted at external URLs linked within the document is not assessed.
  • Color Contrast: While we check for basic text contrast, complex contrast within embedded raster images requires manual review.

Evidence artifact examples

Below are simplified representations of the structured evidence produced during a document audit:

Example: Issue Manifest Snippet

{
  "checkpoint": "Matterhorn 01-002",
  "rule": "Heading levels must not skip",
  "severity": "CRITICAL",
  "location": "Page 4, Paragraph 2",
  "remediation": "Changed H3 to H2 for logical hierarchy"
}

Example: Pass/Fail Conformance Flags

ISO 14289-1: 7.2 Text SemanticsPASS
ISO 14289-1: 13.1 Metadata TitlePASS
WCAG 2.1: 1.1.1 Non-text ContentVERIFIED (MANUAL)

How reviews are performed

The evidence generated by Inkable Docs is used across institutional workflows to validate digital inclusivity. For more details on institutional applications, see our University workflows page.

Accessibility Teams: Use the issue manifest and Matterhorn mapping to perform rapid audits of faculty-produced course materials.

Procurement & Legal: Use the exportable reports as objective evidence of tool-assisted compliance during software evaluation or internal audits.

Consultants: Leverage the "before/after" state tracking to verify that remediation work has been completed to institutional standards.

For a detailed declaration of what is automated, assisted, or explicitly excluded, see our capability boundaries.