PDF/A (archival PDF)
Also known as: archival PDF, pdf-a format, PDF for archiving
PDF/A is a version of the PDF format designed for long-term archiving. It requires everything needed to display the document — fonts, color, and images — to be embedded in the file, so it looks the same decades from now, at the cost of a somewhat larger file.
- ISO standard for long-term PDF archiving
- Embeds fonts and resources for future-proof display
- Slightly larger than an ordinary PDF
What makes PDF/A different
A regular PDF can rely on fonts or resources installed on the computer that opens it. PDF/A is an ISO-standardized subset that forbids that: fonts must be embedded, color must be self-describing, and features that could break over time — like external links to content or encryption — are restricted.
The result is a self-contained file that will render the same way far into the future, which is why governments, libraries, and businesses use PDF/A for records they must keep for years.
Storage trade-off
Embedding fonts and resources makes a PDF/A somewhat larger than the equivalent ordinary PDF. For a single document the difference is minor, but across a large archive it adds up — a deliberate trade of extra space for guaranteed long-term readability.
If you do not need long-term archiving, a standard PDF is smaller, and compressing it further can shrink large scanned documents significantly.