PDF files may be created natively, converted from other electronic formats, or digitized from paper. Businesses, governments, libraries, archives, and other institutions and individuals around the world use PDF to represent considerable bodies of important information. These PDF files should be made accessible to users with disabilities.
Beyond alternative descriptions for images the accessibility of an electronic document depends on a variety of semantic information describing the logical structure and organization of the page content into sections, paragraphs, lists, tables and so on.
In HTML these qualities are accommodated by the language itself. HTML's tags such as <p>, <ol>, <table>, along with ARIA, provide the semantics for the text they contain or mark. In PDF, tags are optional, and don't affect the way in which the page is displayed on-screen. However, if PDF tags are missing, damaged or poorly-considered then the PDF file isn't accessible.
A common source of accessibility requirements are the W3C's Web Content Accessibility Guidelines (WCAG). PDF/UA provides a means of making PDF files that conform to WCAG by defining the correct use of features in PDF.
The primary purpose of ISO 14289, known as PDF/UA, is to define how to represent electronic documents in the PDF format in a manner that allows such files to be accessible. The accessibility of a document is dependent on the inclusion of a variety of semantic information such as (but not limited to):
The inclusion of semantic information in PDF is accomplished by identifying required PDF components as well as restrictions on their use.
PDF/UA operates as a companion standard to be used in conjunction with ISO 32000 (the PDF specification), WCAG 2.x and other standards as may apply for the purpose of achieving accessibility.
By itself, conformity to PDF/UA does not necessarily ensure the accessibility of a document’s content. Cases not covered by PDF/UA include, and are not limited to:
PDF/UA does not cover conversion, or how to achieve conformance; the standard simply states the technical features of accessible PDF documents.
The PDF Association maintains extensive technical resources, including a best practice guide and other educational materials to guide developers and users of PDF/UA.
ISO TC 171 SC 2 WG 9 is presently at work on PDF/UA-2, with publication expected in 2023.
This "dated revision" includes a variety of corrections.
The original PDF/UA specification published in 2012 is no longer available.
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ISO 14289 (PDF/UA) defines the use of tagged PDF to provide a mechanism for reusing PDF page content in the accessibility context.
Communities: PDF/UA TWG, PDF/UA MWG, Accessibility Service Bureau TWG
ISO Group Responsible: ISO TC171 SC2 WG9
ISO Status: status of all PDF-related ISO work
Publications: Tagged PDF Best Practice Guide: Syntax, PDF/UA in a Nutshell, PDF/UA Flyer