PDF/A: The Archival PDF Format Explained

PDF/A is a specialized version of PDF designed for long-term archival storage. Some government agencies, legal systems, and corporate archives require PDF/A specifically. Here’s what makes it different and when you need to care.

What PDF/A is

PDF/A stands for PDF for Archive. It’s an ISO standard (ISO 19005) that defines a restricted subset of PDF specifically designed to be:

Self-contained: all fonts embedded, no external dependencies
Predictable: no features that might not render the same way in the future
Long-lived: structured for compatibility with future PDF readers

A regular PDF can do many things — embed videos, link to external URLs, use external fonts, contain dynamic content. PDF/A strips all of that. The goal: this file, opened in any PDF reader 30 years from now, looks identical to today.

What PDF/A doesn’t allow

Compared to regular PDF:

No JavaScript: scripts can change behavior across PDF versions
No external content: every font, image, color profile embedded in the file itself
No encryption: encryption methods change; future readers might not handle older encryption
No embedded videos or audio: dynamic media doesn’t fit archival
No transparency (in older PDF/A levels): transparency rendering changed across PDF versions
No LZW compression: licensing issues; PDF/A uses other compression
No external font references: fonts must be embedded subset or full

The restrictions ensure that what’s stored is fully self-contained.

PDF/A versions

There are several PDF/A levels with different strictness:

PDF/A-1: original; strictest. Two flavors: PDF/A-1a (more compliant, supports tagged structure) and PDF/A-1b (basic level, visual reproduction only).
PDF/A-2: adds support for transparency, JPEG 2000 compression, layers.
PDF/A-3: allows embedded files (e.g., the original source document attached alongside the PDF).
PDF/A-4: based on PDF 2.0; most recent.

For most archival needs: PDF/A-1b is the safest baseline.

When PDF/A matters

Government records: many regulatory agencies require PDF/A submission for permanent records.

Legal documents: courts often require PDF/A for filings.

Corporate archives: organizations preserving documents for compliance (SOX, HIPAA, etc.) may specify PDF/A.

Library and academic archives: long-term digital preservation.

Specific industry regulations: pharma, finance, government contracting may have PDF/A requirements.

For everyday personal documents: standard PDF is fine. PDF/A is overkill.

How to create PDF/A

From Word: File → Save As → PDF → click Options → check ISO 19005-1 compliant (PDF/A).

From Google Docs: limited direct PDF/A support; download as PDF then convert (see below).

From Adobe Acrobat Pro: File → Save As Other → Archivable PDF.

Online converters: various services convert PDF → PDF/A. Privacy concern for sensitive content.

Specialized tools: pdfaPilot (commercial), veraPDF (free, includes verification).

Verifying PDF/A compliance

Just renaming a file or selecting “PDF/A” in some tools doesn’t guarantee compliance. To verify:

veraPDF (free): the official PDF/A validator. Drop in your file; get a compliance report.

Adobe Acrobat Pro: built-in compliance check.

Online validators: various free options.

For files that will be submitted to agencies requiring PDF/A, validate before submitting.

What gets lost converting PDF to PDF/A

Converting regular PDF → PDF/A:

Lost:

JavaScript actions
External content references
Encryption (if present)
Embedded media (audio/video)
Some fonts (replaced with embedded versions)

Preserved:

All visible text and images
Visual layout
Embedded fonts (now required to be embedded)
Bookmarks and hyperlinks within the document

For typical text-and-image documents, the conversion is mostly invisible.

PDF/A vs PDF/X vs PDF/E

Other specialized PDF subsets:

PDF/X: for print production (specific color requirements, no transparency in some versions).

PDF/E: for engineering (CAD-like features).

PDF/UA: for accessibility (universal accessibility — required for some government documents).

PDF/A is for archival; these others have different purposes.

File size

PDF/A files are typically:

Similar size to standard PDFs when the source already embedded fonts
Slightly larger when standard PDFs referenced system fonts (PDF/A must embed them)
Smaller if standard PDFs contained removable features (videos, scripts)

Don’t expect major file size changes either direction.

Practical advice

For most users:

Regular PDF is fine for: emails, sharing, online documents, casual archives, anything that won’t be required to remain unchanged in 30+ years.

PDF/A is needed when: a specific recipient (government, legal, regulatory body) requires it.

If asked for PDF/A specifically:

Check which version they want (PDF/A-1b is most common)
Use Word/Acrobat to export as PDF/A
Validate with veraPDF or similar
Submit

Otherwise: don’t worry about PDF/A. Standard PDF works for everything else.

Special case: scanned PDF/A

Sometimes archival requires:

PDF/A format
OCR’d text layer for searchability
High-resolution images

Workflow:

Scan at 300+ DPI as TIFF
Convert to PDF
Run OCR to add text layer (PDF OCR)
Export as PDF/A through Acrobat Pro or similar

For permanent archive of scanned documents, this combination is the gold standard.

TL;DR

PDF/A: a subset of PDF designed for long-term archival
Restrictions: no JavaScript, no external content, all fonts embedded, no encryption
Versions: PDF/A-1, -2, -3, -4 with varying capabilities
When you need it: government, legal, regulatory archives — when specifically requested
For everyday use: regular PDF is sufficient
Creating: Word’s “ISO 19005-1 compliant” option, or Acrobat Pro
Validating: veraPDF (free)
For scans needing archival: combine PDF OCR + PDF/A export