The Problem PDF/A Solves
Imagine opening an important contract from 15 years ago, only to find the fonts are missing, embedded graphics are broken, and the file won't open without a plugin that no longer exists. This is a real problem with standard PDFs — they can contain dependencies on external resources that may disappear over time.
PDF/A (PDF for Archiving) was created to prevent this. It is an ISO standard (ISO 19005) that defines a subset of the PDF specification designed for long-term document preservation. A PDF/A file is completely self-contained: every font, color profile, and resource the document needs is embedded inside the file itself.
What PDF/A Prohibits
- External content: No links to external fonts, images, or data sources.
- Encryption: Password protection is not allowed — archives must be accessible.
- JavaScript: No dynamic or executable content.
- Audio and video: Multimedia embeds are prohibited in most PDF/A versions.
- LZW compression: Some legacy compression algorithms with patent concerns are excluded.
PDF/A Versions Explained
| Version | ISO Standard | Based On | Key Differences |
|---|---|---|---|
| PDF/A-1 | ISO 19005-1 (2005) | PDF 1.4 | Most restrictive. No transparency, no layers. Two conformance levels: A (full accessibility) and B (basic). |
| PDF/A-2 | ISO 19005-2 (2011) | PDF 1.7 | Allows transparency, layers, JPEG 2000, and embedding of other PDF/A files. |
| PDF/A-3 | ISO 19005-3 (2012) | PDF 1.7 | Same as PDF/A-2 but allows embedding of any file type as attachments. |
For most archiving needs, PDF/A-2b (basic conformance of version 2) is the recommended choice.
Who Actually Needs PDF/A?
- Legal and courts: Many court systems in the US, EU, and Australia require PDF/A for electronic filing.
- Government agencies: NARA (US National Archives), the EU, and many national governments mandate PDF/A for records.
- Healthcare: Medical records that must be retained for decades benefit from PDF/A's guaranteed readability.
- Banking and finance: Contracts, statements, and compliance documents stored for regulatory periods.
- Any business that needs to access documents reliably in 10, 20, or 50 years.
How to Create a PDF/A File
Using LibreOffice (Free Desktop)
In LibreOffice Writer, go to File → Export as PDF. In the dialog, check Archive PDF/A and select your desired version. LibreOffice handles font embedding and metadata automatically.
Using Ghostscript (Command Line)
gs -dBATCH -dNOPAUSE -dCompatibilityLevel=1.7 \
-sDEVICE=pdfwrite -dPDFA=2 -dPDFACompatibilityPolicy=1 \
-sOutputFile=output_pdfa.pdf input.pdf💡 Validation Tip: After creating a PDF/A file, always validate it with a tool like veraPDF (free, open source) to confirm it truly meets the standard.
PDF/A vs. Regular PDF: Practical Differences
For everyday viewing, a PDF/A file looks and works identically to a regular PDF. The differences are entirely under the hood — in how the file stores its resources and what features it omits. PDF/A files are sometimes larger than equivalent standard PDFs because everything (all fonts, all color profiles) must be embedded. This is acceptable — the goal is preservation, not compression.