Earlier this week, when I considered how best to save websites using Safari, I pointed out that the PDFs it saves aren’t intended to be in archival format, using one of the PDF/A standards. As some of you pointed out, Preview has an option to export PDFs in “PDF/A” format. This article examines whether those are suitable for archiving.

PDF/A

PDF is a generic document type and includes a multiplicity of different standards. Standard PDF generated by the Quartz 2D engine should comply with PDF version 1.4, from 2001, although the first open ISO standard of 2008 was based on version 1.7, and the current ISO standard is version 2.0. There are also five specialised subsets of PDF, among them PDF/A intended for archival purposes, each with their own families of ISO standards.

PDF/A was originally based on PDF version 1.4, but more recently has adopted 1.7. Its standards impose additional restrictions on core features, such as requiring all fonts to be embedded, and forbidding the use of encryption and LZW compression. Its standards are based on three levels of conformance: basic (B), accessible (A), and full Unicode text (U). The two standards and levels in most common use are PDF/A-2A (accessible) and PDF/A-2B (basic). A more detailed account is given in Wikipedia’s article.

Although Preview claims to export PDF documents in PDF/A format, I’ve been unable to discover which standard or level those are intended to comply with. However, each of the test documents is reported by Adobe Acrobat CC (Pro) as claiming compliance with PDF/A-2B in ISO 19005-2.

Conformance

Three test PDF documents were used, two saved from Safari 26.1 (macOS 26.1) as detailed previously, and the Help book for LogUI, written by Nisus Writer Pro. All three were opened in Preview 11.0 (1113.2.5) and Exported As PDF/A, with just the Create PDF/A option ticked in the File Save dialog.

All three exported PDFs were then opened in Adobe Acrobat ‘Pro’ version 2025.001.20841. That reported that each claimed “compliance with the PDF/A standard”, so opened them read-only to ensure they couldn’t be modified. When each was verified against PDF/A-2B, that failed.

Details of the compliance failures were then obtained using Acrobat’s Preflight feature. In each there were multiple errors, such as those shown below.

To assess what changes were required to make the LogUI help book compliant with the standard, Acrobat then performed the conversion. Corrections it made are shown below.

Although those were quick and simple, without them the file exported from Preview wasn’t considered by Acrobat to comply with the standard.

When do you need to use PDF/A?

Although I’m confident that PDF documents created using the engine in Quartz 2D in macOS Tahoe will remain fully accessible for at least the next 20 years or more, looking 50 or 100 years ahead the use of a major open standard intended and widely used for archives becomes more important. Whether the imperfect PDF/A exported by Preview would make any difference to that is unclear.

If you intend any PDF documents created on Macs to be true archives that should stand the test of long times, then you should convert them into PDF/A-2B or another appropriate standard before committing them to archival storage. Otherwise, it’s moot whether Preview’s conversion is a good investment of your time.

Summary

• According to Adobe Acrobat, the ‘PDF/A’ format exported by Preview doesn’t comply with its claimed standard of PDF/A-2B. Thus the answer to the question posed by the title is no, not quite.
• If a PDF is intended to be accessible for decades into the future, it should be converted to a recognised PDF/A standard such as PDF/A-2B using Adobe Acrobat or an equivalent.
• Other PDFs may as well be left in their original format, which should ensure their accessibility for at least the next 20 years or more.