Registry of Accessibility Values

Status of this Document

This document is not subject to semantic versioning. Changes will be tracked within the document.

Editors:

Copyright © 2012-2026 Editors and contributors. Published by the IIIF Consortium under the CC-BY license, see disclaimer.

Abstract

This document lists a set of allowed values for the Presentation API provides property that have been identified as useful for implementations, especially related to accessibility. They may be defined by the IIIF community, or outside of it.

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1. Introduction

This is one of a number of IIIF registries. It lists a set of allowed values for the Presentation API provides property that have been identified as useful for implementations, especially related to accessibility. They may be defined by the IIIF community, or outside of it.

1.1. Disclaimer

The inclusion of entries in this document that are outside of the IIIF domain must not be interpreted as endorsement, support, or approval from the editors, the IIIF community or any individual. This annex is provided as a registry to advertise the existence of these extensions and attempt to ensure some consistency between implementations for common but not universal requirements.

1.2. Inclusion Process

The process for having a new entry added to this registry is described here.

2. Requirements for Inclusion

3. Registry

This table summarizes the known values available for use with the Presentation API provides propery, which defines accessibility functionality that a linked resource enables for its target, describing why and how a client might use it rather than what the resource is by type or format. The current approved values are defined by Schema.org’s Accessibility Properties for Discoverability Vocabulary and the IIIF Community.

Value Description Source
closedCaptions Schema.org
alternativeText Schema.org
audioDescription Schema.org
longDescription Schema.org
signLanguage Schema.org
highContrastAudio Schema.org
highContrastDisplay Schema.org
braille Schema.org
tactileGraphic Schema.org
transcript Schema.org
translation IIIF
subtitles IIIF

Appendices

A. Acknowledgements

Thanks to the members of the IIIF for their continuous engagement, innovative ideas and feedback.

B. Change Log

Date Description
2026-XX-YY New Version 4 Registries