PDF/A, explained: documents that survive decades

Open a Word document from 2004 and there is a decent chance the fonts look wrong, an image is missing, or the layout has quietly shifted. Now imagine that document is a property deed, a medical record, or a court filing that has to be readable in 2050. That is the problem PDF/A was built to solve.

What PDF/A actually is

PDF/A is an archival profile of PDF, standardized as ISO 19005. It is not a different file format with a new extension. A PDF/A file is still a PDF and still opens in any reader. What changes is that the file follows a strict subset of the format, designed so the document will render the same way decades from now, on software that may not even exist yet.

The core idea is self-containment. A regular PDF can rely on things outside itself: a font installed on your machine, a color profile, an external file, a script that fetches content. Any of those dependencies can disappear over time. PDF/A removes them.

Why the standard exists

Long-term preservation has a few hard requirements, and PDF/A turns each one into a rule:

• Embedded fonts. Every font used in the document must be embedded inside the file. The reader never has to guess or substitute, so text always renders with the correct glyphs and spacing.
• No external dependencies. No links to external content, no audio or video pulled from elsewhere, no JavaScript, no encryption that could lock the file out of future readers. Everything the document needs lives in the document.
• Device-independent color. Color is defined in a way that does not depend on a specific monitor or printer. Files commonly carry an sRGB color space so that a shade of blue looks the same on any compliant viewer, today or in thirty years.
• Metadata you can read. Document metadata is stored in a standardized, machine-readable form, which makes large archives searchable and auditable.

Put together, these rules mean a PDF/A file is a closed, predictable object. That predictability is exactly what an archive needs.

PDF/A-1, PDF/A-2 and PDF/A-3

The standard has evolved in parts, each based on a newer generation of PDF:

• PDF/A-1 (2005) is the original, based on PDF 1.4. It is the strictest and most widely supported. It does not allow newer features like JPEG2000 compression, transparency, or layers.
• PDF/A-2 (2011) is based on PDF 1.7 (ISO 32000-1). It keeps the archival guarantees but adds modern capabilities: better compression, transparency, layers, and the ability to embed other PDF/A files. For most documents it is the sweet spot between fidelity and compatibility.
• PDF/A-3 (2012) is almost identical to PDF/A-2, with one key difference: it lets you attach arbitrary files of any type (for example, the original spreadsheet or an XML invoice) alongside the archived page. That flexibility is powerful but also looser, which is why pure archives often prefer the discipline of PDF/A-2.

Each part also has conformance levels. The common ones are b (“basic”), which guarantees reliable visual reproduction, and a (“accessible”), which additionally requires a tagged structure for accessibility.

On files.co, conversions produce PDF/A-2b: based on the modern PDF 1.7 baseline (ISO 19005-2), with embedded fonts and faithful visual reproduction. It is the format most public administrations and archives accept, and it avoids the unnecessary attachment looseness of PDF/A-3.

When to use PDF/A

Reach for PDF/A whenever a document has to outlive the software that created it:

• Public administration. Many filing systems and e-government portals require or recommend PDF/A for submissions, contracts, and official records.
• Legal. Court filings, evidence, deeds, and notarial documents need to be reproduced exactly, years later, without ambiguity.
• Archives and records management. Libraries, hospitals, universities, and corporate records departments use PDF/A as their preservation format of choice.

For everyday sharing, a normal PDF is fine. PDF/A is for the documents you cannot afford to lose or have render incorrectly.

How to convert on files.co

On files.co the conversion happens locally, in your browser. You drop a PDF in, the tool embeds the fonts, normalizes the color to sRGB, strips the disallowed elements, and writes out a valid PDF/A-2b file. Your document never leaves your device and is never uploaded to a server, which matters when the file is a contract or a medical record.

A document that survives decades should not have to travel across the internet to become one. Convert it where it already lives, and keep a copy that will still open long after the app you made it in is gone.