What Is PDF/A and When Do You Need It?

PDF/A is defined by the ISO 19005 standard. It is a restricted form of PDF meant for long-term preservation. A conforming file contains everything needed to display it identically in the future: fonts are embedded, colour information is included, and features that depend on external resources or running code are not allowed. In practice this means no encryption, no JavaScript and no links to fonts or content stored elsewhere.

PDF/A-1 is based on PDF 1.4 and does not allow transparency. PDF/A-2 is based on PDF 1.7 and adds features such as transparency and better compression. PDF/A-3 is like PDF/A-2 but also allows other file types to be embedded as attachments. Each has conformance levels, and which one you need depends on who is asking. If a body asks for PDF/A, check whether they name a specific version.

Organisations that keep records for years, such as archives, libraries, legal systems and some public bodies, may require or prefer PDF/A so their files remain readable. Requirements vary, so read the submission guidelines carefully and note whether they call it mandatory, preferred or simply recommended.

Our tool populates missing document metadata, such as the title, author and date, and adds a declaration that the file is intended to conform to PDF/A-2b. It does not re-encode fonts, add an embedded colour profile or check every rule in ISO 19005. That means the output is not guaranteed to pass a strict validator. It can be helpful for preparing a file, but it is not a substitute for certified conversion.

If PDF/A compliance is legally or contractually required, use specialist software and validate the result with a dedicated checker such as veraPDF.

Remove any password protection first, because encrypted files cannot be PDF/A. Avoid unusual fonts that are not embedded in the original, and keep a copy of the untouched file. If a validator rejects the converted file, the report will usually name the cause, such as a missing font or transparency in a PDF/A-1 file.

Many everyday submissions do not need it. If a form simply asks for a PDF, a normal PDF is fine. PDF/A is worth the effort when a body explicitly requires it or when you are producing records you want to be readable far into the future.

If you are not sure, ask the organisation which version and conformance level they expect, or whether a standard PDF is acceptable. Their answer saves you from doing work you did not need to do.

If you still have the original document, creating PDF/A at export is far more dependable than converting an existing PDF, because the program has the real fonts and colours to hand. In Microsoft Word, choose Save As, pick PDF, open Options and tick the PDF/A compliance box. In LibreOffice, choose Export as PDF and tick the Archive (PDF/A) option, where you can also select the version. Scanning software often has a PDF/A setting too.

Converting afterwards is the fallback for when the source is gone. That is where missing fonts and transparency cause trouble.

A PDF/A file carries a declaration in its metadata. Many viewers show it: Adobe Acrobat Reader, for example, displays a bar at the top saying the file claims compliance with the PDF/A standard and opens it read-only. The word “claims” matters. The declaration only says what the file is supposed to be. Whether it truly meets the rules is a question for a validator such as veraPDF, which tests the file and lists each failure.

The “b” in PDF/A-2b stands for basic: the file will look the same in future. Level “a”, for accessible, adds requirements for tagged structure so the reading order and headings are preserved as well. Level “u” requires that all text can be mapped to Unicode, so it stays searchable. When a body names a level, it will most often be “b”. There is also a newer PDF/A-4, based on PDF 2.0, which few submission systems ask for yet.