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Understanding Private Data in PDF/A

From comments to internal workflow metadata, attachments, retired features, proprietary extensions, and more, almost all file formats allow for the inclusion of information that isn’t fully described by the format specification, and which may not be obvious or even visible to end users. Although such unspecified data is routine, software only handles data that it was specifically written to support – it has little choice but to either ignore that which it doesn’t recognize, or generate an error message.

This Application Note delivers the facts about private data in PDF. A “Q&A” section addresses private data in a PDF/A-4 context, including numerous specific cases. Sections include:

  • The history of private data in PDF and nested formats
  • PDF’s extensibility, including support for private data and what not to do
  • Processor requirements
  • Private data in the PDF/A context
  • An extensive Q & A, including specific examples of private data

This document was developed by the PDF/A Technical Working Group (TWG) based on a request from the US National Archives and Records Administration (NARA), an Institutional member of the PDF Association.


Technical questions about this Application Note are most effectively addressed by the PDF/A TWG. If you are not a member of the PDF Association but wish to offer a comment on this document, please write to pdfa-twg@pdfa.org.


Download Understanding Private Data in PDF/A

This Application Note provides information regarding the valid inclusion and use of private data in PDF and PDF/A files.

Published by the PDF Association © 2024

Developed by the PDF/A TWG.


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