You might have encountered a situation where a government portal or legal system rejected your PDF upload, insisting that the file must be in "PDF/A" format.

While they look identical when opened, a standard PDF and a PDF/A are fundamentally different under the hood.

What is a Standard PDF?

A standard PDF (Portable Document Format) is designed to look the same on any device. However, to keep file sizes small, a standard PDF often relies on the computer it is opened on to provide certain resources.

For example, if the PDF uses the "Arial" font, it might not store the font data inside the file. It assumes the viewing computer has Arial installed. If you open that PDF 50 years from now on a computer that doesn't have Arial, the document will look different or become unreadable.

What is PDF/A?

PDF/A (where the "A" stands for Archiving) is an ISO-standardized version of PDF designed specifically for long-term preservation.

The core philosophy of PDF/A is that the file must be 100% self-contained. It cannot rely on any external software, fonts, or environments to render exactly as it was created.

Restrictions in PDF/A

To achieve this self-containment, the PDF/A standard strictly forbids certain features allowed in standard PDFs:

  1. Audio and Video: You cannot embed multimedia content in a PDF/A because the software required to play it might not exist in the future.
  2. JavaScript: Executable code is banned because it introduces security risks and relies on external runtime environments.
  3. Encryption: PDF/A files cannot be password-protected or encrypted. Archives must be openly accessible to the archivist.
  4. External References: All fonts, color profiles, and images must be embedded within the file itself.

When Do You Need PDF/A?

You generally only need to use PDF/A when it is explicitly requested by an institution. Common use cases include:

  • Legal Systems: Courts often require digital filings to be in PDF/A format to ensure the record remains intact indefinitely.
  • Government Archives: Submitting official documents to government bodies.
  • Corporate Record Keeping: Companies archiving financial reports, HR records, or compliance documents for decades.
  • Academic Theses: Many universities require final digital dissertations to be submitted in PDF/A.

If you are just emailing a contract to a client or uploading a brochure to a website, a standard PDF is perfectly fine and usually preferred due to its smaller file size.

How to Convert PDF to PDF/A

If you have a standard PDF and an institution demands a PDF/A, you must convert it. This process embeds missing fonts and strips out banned content.

Many desktop PDF editors (like Adobe Acrobat Pro) offer a "Save as PDF/A" option.

If you don't have specialized software, you can use ToolzStack's Document Converter to ensure your file meets the rigorous PDF/A standards for compliance.

Related guides: What is a PDF File? · PDF vs DOCX