Overview
ISO/IEC 23761:2021 - "Digital publishing - EPUB accessibility - Conformance and discoverability requirements for EPUB publications" defines how to verify and describe the accessibility of EPUB publications. The standard specifies both content conformance requirements (how to evaluate that an EPUB is accessible) and accessibility metadata requirements (how to expose accessibility information so publications are discoverable by users, retailers and libraries). It applies to EPUB publications across versions and profiles, and complements WCAG 2.0 by defining EPUB‑specific application and reporting practices.
Key topics and requirements
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Discoverability (Clause 6)
- EPUB package documents must include accessibility metadata that travels with the publication.
- Required metadata: Access modes, Accessibility features, Accessibility hazards, Accessibility summary.
- Recommended/optional metadata: Sufficient access modes, Accessibility APIs, Accessibility controls.
- Linked metadata records are allowed but cannot replace package metadata for discoverability.
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Accessible publications (Clause 7)
- Leverages WCAG 2.0 principles (perceivable, operable, understandable, robust) and explains how to apply WCAG conformance across a collection of web documents (an EPUB).
- Specifies EPUB‑specific requirements such as page navigation, media overlays playback, and conformance reporting.
- Introduces the concept of conformance evaluation and reporting for certification of accessible EPUBs.
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Optimized publications (Clause 8)
- Defines how to identify publications optimized for particular user needs that may not meet broad accessibility requirements, and how to represent those optimizations in metadata.
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Supportive material
- Abstract, technique‑oriented approach; companion document "EPUB Accessibility Techniques" provides implementation guidance and distribution techniques.
Practical applications - who uses it
Open preview (PDF)Digital publishing — EPUB accessibility — Conformance and discoverability requirements for EPUB publications
