- August 19, 2013
For most documents, PDF is usually all you need to enable everyday readability and sharing. If you need to ensure those documents are readable over the long-term, however, PDF/A should be your go-to format in your PDF software. Here’s why.
What is PDF/A?
PDF/A is an ISO-standardized version of the Portable Document Format (PDF) created specifically to enable you to preserve electronic documents over the long haul. PDF/A ensures that any documents you archive will keep their appearance and readability, regardless of which PDF software applications or systems you use to create them. You’ll get more predictable, consistent results from PDF/A, because of its ISO-standard compliance, than you will from plain PDF. That’s exceptionally useful if you’re expecting those documents to be accessed far into the future.
How is PDF/A different from PDF?
PDF/A eliminates a few features that don’t work well for long-term archiving.
While standard PDF doesn’t embed fonts into the file, PDF/A requires font embedding to ensure that you’ll be able to read text. That means if you’re planning to archive your document, it’s important to choose fonts that can be embedded into PDF, such as Times, Helvetica and Arial, and save fancy fonts that can’t be embedded for other uses.
Also, while it can be handy to have a lot of different software applications that can create PDFs today, it can lead to issues. With its ISO standardization, PDF/A helps ensure that a wider variety of PDF readers will be able to read your file in the distant future. It also provides a user interface for reading embedded annotations, ensuring that notes are retained, so you can use PDF annotate (commenting) features. And ISO-standard PDF/A adheres to color management guidelines that PDF doesn’t always, which helps guarantee that documents opened in 2053 look the way they looked in 2013.
If you need to sign documents, PDF/A does support digital signatures but there’s a caveat. They have to conform to PDF/A requirements for visual appearance. That means that when you sign documents, you have to use embeddable fonts and device-independent color in the signature. Not all commercial digital signatures tools follow these requirements so make sure you check documentation first.
When should you use PDF/A?
Any time you anticipate that the document you’re creating is going to be archived for a long time, and you want to ensure its look and feel is intact when it’s opened, you should use PDF/A.
That means everyday documents, such as spreadsheets, presentations and reports, that you use and change frequently are probably fine saved as PDF. But electronic documents that you’re preserving for posterity—such as historical, legal, government and court records—could benefit from the PDF/A archival format.
How does PDF/A compare to PDF/E and PDF/X? That’s a topic for upcoming articles, so stay tuned.