Sustainability of Digital Formats: Planning for Library of Congress Collections

PDF/A-4e is defined in ISO 19005-4: Document management — Electronic document file format for long-term preservation Part 4: Use of ISO 32000-2 (PDF/A-4) Annex B: Requirements for PDF/A for Engineering. Note that the PDF Association states that "a formal dated revision of PDF/A-4 is currently being prepared by ISO TC 171 SC 2 WG 5" in 2025 and errata are listed on the PDF Association's GitHub repository. PDF/A-4e is a subtype of PDF/A-4 and the specification states that "PDF/A-4e [is] a synonym for ISO 19005-4 Level E conformance." In fact, PDF/A-4e is the successor to PDF/E. See PDF/A-4 for general file and structure information and PDF/A_family for more details on the PDF/A family of standards.

PDF/A-4e supports RichMedia and 3D Annotations as well as embedded files. In PDF/A-4, 3D artwork can be represented in either of these annotation types, but use of the RichMedia annotation type is recommended. Note that the RichMedia annotation Subtype entry can only have the value of 3D to ensure "only 3D and not audio or video information is included in a PDF/A-4e." In the 3D annotation type, the 3D model must be in U3D or PRC format. However, "embedded data streams containing 3D data and referenced from a RichMedia assets tree can use other 3D formats" including STEP and glTF (GL Transmission Format) Family provided that "all file specification dictionaries present in either the Assets name tree of a RichMediaContent Dictionary or the Asset entry in RichMediaInstance dictionary shall contain a Subtype key whose value is a valid IANA Media Type, as well as the F and UF keys" (see Understanding private data in PDF/A section 5.2.5). In addition, the RichMedia annotation type includes support for textures and additional scripting events not supported by the older 3D annotation type. An interactive conforming processor able to render 3D content should also be able to process JavaScript actions -- but only when invoked explicitly by a user. An interactive conforming processor that cannot process such actions shall inform the user of this situation. As noted in Understanding private data in PDF/A, "PDF/A-4e allows JavaScript to be in a PDF/A file but requires that “... they are invoked explicitly by a user (such as via outlines or buttons). A conforming processor, that is non-interactive, shall not execute them at all." See also ISO 21757-1:2020 Document management — ECMAScript for PDF — Part 1: Use of ISO 32000-2 (PDF 2.0) (December 2020) which relates to scripting actions, including some specific to 3D and RichMedia annotations. The goal of ISO 21757-1 is to enable the implementation of ECMAScript/Javascript processors to provide interoperable scripting and automation of PDF documents.

PDF/A-4e files can also contain embedded files and therefore may contain an EmbeddedFiles key in the document catalog dictionary. In such cases, the file specification dictionaries present in the value of the EmbeddedFiles key must also conform to the requirements of PDF/A-4f. In addition, "although embedded files that do not comply with any part of this document should not be rendered by a conforming PDF/A-4e processor, a conforming interactive PDF/A-4e processor should enable the extraction of any embedded file. The conforming interactive PDF/A-4e processor should also require an explicit user action to initiate the process."

See also PDF/A_family.

Overall adoption of PDF 2.0-based formats such as PDF/A-4f and PDF/A-4e is still emerging in the marketplace. Several platforms note support for PDF/A-4e such as iText Core/Community 9.2.0, Scanshare v5.23.10 (October 16, 2023), Power PDF and CIB pdf toolbox. Docusign in their PDF/A Conversion and Compliance (see link from navigation tree on https://support.docusign.com/) specifically states that as of July 2025, it does not support PDF/A-4e (or PDF/A-4f). See also PDF/A-4. Comments welcome.

See also PDF/A_family and PDF/A-4.

Accessibility Features

PDF/A-4e has no specific support for digital accessibility. See PDF/A-4 which recommends following the PDF/UA standard, which provides detailed guidelines and technical specifications for creating accessible tagged PDFs.