How to Convert a PDF to PDF/A for Long-Term Archiving

PDF/A is a restricted version of PDF designed so that a file opened in fifty years looks the way it does today. Courts, national archives, universities and regulators increasingly require it.

Convert to PDF/A

1. 1Open the PDF to PDF/A tool and add your document.
2. 2Convert. Fonts are embedded, the colour handling is made explicit, and the archival metadata is written in.
3. 3Keep the original alongside the archival copy — conversion is one-way in spirit.

What makes a PDF archival

The core idea is self-containment: everything needed to render the page must be inside the file, and nothing may depend on the outside world.

• Fonts must be embedded, so the document does not depend on what is installed later.
• Colour must be unambiguous, with an explicit colour space rather than "whatever the device does".
• No external references — no linked images, no fetched content.
• No encryption, because a future reader must be able to open it.
• No JavaScript, no audio, no video, no executable content.
• Structured XMP metadata declaring the conformance level.

The conformance levels

If a requirement just says "PDF/A", level 1b or 2b is what is normally meant. Ask if the answer determines whether a filing is accepted.

What conversion changes

Expect the file to grow, because fonts that were previously referenced now have to be carried inside it. Expect encryption and interactive content to be stripped, since neither is permitted. And expect transparency effects to be flattened when converting to the older levels — which is why you keep the original.

Validate before you rely on it

A file can declare PDF/A conformance and still fail validation — usually because the converting tool wrote the metadata without enforcing every rule. If acceptance by a court, a registry or an archive depends on conformance, run a validator rather than trusting the declaration.

What to archive alongside the file

• The original PDF, which is smaller and unconstrained.
• A note of the conformance level, so future readers know what was claimed.
• The date of conversion and the tool used.
• A checksum, so future corruption can be detected rather than guessed at.

An archive is a system rather than a file format. PDF/A guarantees the document will render; the surrounding records are what let anyone verify it is the document that was deposited.