TIFF vs PDF/A: which format is better for long-term electronic record preservation?

Both TIFF and PDF/A are widely accepted for long-term preservation, and many programs use both. The better choice depends on the nature of the content, not on one format being universally superior.

What each format does well

TIFF (Tagged Image File Format) stores raster images, essentially a grid of pixels. It is a mature, openly documented format with decades of broad support, which makes it a dependable choice for preserving scanned images of paper, photographs, and other purely visual content. Because uncompressed (or losslessly compressed) TIFF captures pixel data directly, it is well suited to faithful image capture. Its limitations are that it does not store searchable text on its own, files can be large, and it carries little structure for multi-part documents.

PDF/A is an ISO-standardized profile of PDF created specifically for archiving. It requires that everything needed to render the file in the future be embedded in the file itself, including fonts and color information, and it prohibits features that depend on external resources or software. PDF/A can hold searchable text, multiple pages, and metadata in one self-contained package, which makes it a strong fit for born-digital documents and for text-bearing records where searchability and structure matter.

How to choose

• Born-digital text documents (reports, correspondence, forms): PDF/A generally preserves text, layout, and metadata more completely.
• Scanned or photographic images where exact pixel fidelity is the priority: TIFF is a common archival master. Many programs scan to TIFF masters and also generate searchable PDF/A access copies.
• Mixed or multi-page documents: PDF/A handles structure and embedded text in a single object.

Principles that matter more than the format

Format selection is one part of a sound digital preservation strategy. Prioritize open, well-documented, widely supported formats; capture and retain descriptive and technical metadata; record fixity information so you can detect corruption; and plan for periodic format review and possible migration as technology evolves. Whatever format you choose, ensure your imaging meets recognized quality guidelines and that the result remains authentic, reliable, and usable for the full retention period.

For more on managing digital records over time, see the electronic records topic hub.