A regular PDF is designed to look the same on any screen today. PDF/A is designed to look the same decades from now, on software that does not exist yet. It is an ISO standard (ISO 19005) used by courts, governments, libraries, and companies with record-keeping obligations.
What PDF/A requires
PDF/A is a restricted subset of PDF. A conforming file must be self-contained:
- All fonts embedded, so text renders identically without the original fonts.
- No encryption or passwords, so the file can always be opened.
- No JavaScript or executable actions.
- No external content dependencies, such as fonts or images loaded from elsewhere.
- Device-independent color, defined with embedded color profiles.
- Standardized metadata stored as XMP.
Versions
| Version | Based on | Notable additions |
|---|---|---|
| PDF/A-1 (2005) | PDF 1.4 | The original archival profile |
| PDF/A-2 (2011) | PDF 1.7 | Transparency, layers, JPEG 2000, embedding PDF/A files |
| PDF/A-3 (2012) | PDF 1.7 | Embedding any file type, such as XML invoice data |
| PDF/A-4 (2020) | PDF 2.0 | Simplified levels aligned with PDF 2.0 |
Conformance levels
- b (basic): the visual appearance is preserved reliably.
- u (Unicode): level b, plus all text can be extracted as Unicode for search and copy.
- a (accessible): level u, plus tagged structure for screen readers and reflow.
When you need PDF/A
You need it when someone requires it: court e-filing systems, tenders, regulators, or your organization’s records policy. For everyday sharing, a normal PDF is fine and often smaller.
Preparing a document for archiving
Even without full PDF/A conversion, you can make a PDF more archive-friendly in your browser:
- Flatten forms and annotations so values are fixed on the page.
- Clean up metadata so the title and author are accurate.
- Remove passwords before archiving, since encrypted PDFs cannot be PDF/A.
Always run the final file through the validator your recipient uses. Conformance is strict, and visual inspection is not enough to prove compliance.