The PDF format has a number of features that don’t fit with the aims of long-term preservation and accessibility, such as encryption, password protection, external fonts and reliance on external software. Some examples are PDFs that use Quicktime content. Acrobat cannot render this format natively, and relies on an external player. Also files that use Linux fonts, or files with 3D content.
Institutions may want to check their PDF files to similar examples. Reasons for doing this include:
Check compliance with institutional policy (e.g. do not accept PDFs with passwords)
Check collections for preservation risks (e.g. embedded multimedia content)
- qpdf gives detailed information about encryption and password protection
- pdffonts tool that is part of xpdf is useful for checking whether fonts in a PDF are embedded
- The professional version of Adobe Acrobat has a PDF/A validator built into its Preflight tool
- PDF/A validator that is part of the open-source Apache PDFBox library
- VeraPDF has the potential to develop into a full-fledged PDF validator
- Ensuring long-term access: PDF validation with JHOVE?
- PDF/A, PDF for Long-term Preservation
- Preserving the Data Explosion: Using PDF - 25 April 2008
- New ISO standard will ensure long life for PDF documents - 7 October 2005