PDF/A is a subset of PDF — it's a more restrictive version of the format designed specifically for long-term document archiving. Most people encounter it when a government portal, a legal system, or an archival requirement specifies "PDF/A format only." Understanding what makes PDF/A different from a regular PDF explains why it exists and when you actually need it.
What Standard PDF Allows That PDF/A Prohibits
A standard PDF Format is flexible. It can contain JavaScript that runs when the document is opened, links to external resources that load at viewing time, encrypted content, embedded multimedia like audio and video, and fonts that aren't fully embedded — relying on the viewer to supply them from the local system.
All of these features create dependencies on external systems or software that may not exist in the future. A PDF with an embedded video requires a video codec. A PDF with external font references requires those fonts to be installed. A PDF with JavaScript requires a viewer that executes JavaScript. In twenty years, any of these dependencies might be unavailable.
What PDF/A Requires
PDF/A is designed to be completely self-contained. Every element the document needs to display correctly must be embedded in the file itself — no external dependencies allowed. Specifically, PDF/A requires:
- All fonts fully embedded: every typeface used in the document must be embedded in full, not referenced from the system or partially embedded.
- No external content references: no links to external files, no content loaded from URLs at viewing time.
- No JavaScript: no executable content that depends on software interpretation.
- No encryption: content must be fully accessible — password protection prevents future access if passwords are lost.
- Color profiles embedded: colors must be described with embedded ICC profiles so the document reproduces consistently regardless of the display system.
- Document metadata: specific XMP metadata fields must be present, including the PDF/A conformance declaration.
PDF/A-1, PDF/A-2, PDF/A-3: What's the Difference?
- PDF/A-1 (2005): the original and strictest version, based on PDF 1.4. No transparency, no layers, no JPEG 2000 compression. The most universally supported by archival systems.
- PDF/A-2 (2011): based on PDF 1.7. Allows transparency, layers, JPEG 2000 compression, and embedding of PDF/A files within PDF/A files. More modern and flexible while maintaining archival reliability.
- PDF/A-3 (2012): similar to PDF/A-2 but allows embedding of any file type (not just PDF/A) within the archive document. Used for embedding XML invoices, source files, or other attachments alongside the visual document.
Each version also has conformance levels: A (full accessibility, with tagged structure), B (basic, visual reproducibility only), and U (Unicode mapping). PDF/A-1b is the most commonly required by archival systems — it ensures the document looks the same but doesn't require full accessibility tagging.
When You Actually Need PDF/A
PDF/A is required or strongly recommended in specific contexts:
- Government and legal submissions where long-term record retention is mandated by law
- Court filings in jurisdictions that require archival-compliant formats
- Financial and accounting records with multi-year retention requirements
- Healthcare records where documents must remain readable for the patient's lifetime
- Any organization with a formal document management system specifying PDF/A for archived records
For everyday business documents — proposals, reports, invoices, correspondence — standard PDF Archive via a regular PDF is perfectly adequate. PDF/A's restrictions are worth the tradeoff only when you need the guarantee of future readability across decades, not just years.
How to Create a PDF/A File
In Microsoft Word, File > Save As > PDF > Options > check "ISO 19005-1 compliant (PDF/A)" produces a PDF/A-1b file directly. This is the simplest path for Word documents.
Adobe Acrobat Pro can convert an existing PDF to PDF/A using the Preflight tool (Tools > Print Production > Preflight > PDF/A compliance). It checks the document against PDF/A requirements and fixes or flags any issues — fonts not embedded, external references, prohibited content. For organizations regularly producing archival documents, this workflow ensures compliance before filing.