PDF compression guides
How to Prepare a PDF for Archival Storage
Treat long-term preservation as a controlled records task, not simply as a smaller-file task.
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For archival preparation, identify the repository's required PDF/A profile, metadata, fonts, signatures, color handling, and validation process before compressing anything. Keep the authoritative source, make a working copy, and validate the final file with the repository's approved tools. A smaller PDF may be easier to store, but it is not archival-compliant merely because it opens or has fewer bytes.
Start with the repository specification
Archival work has requirements that ordinary web delivery does not: a defined conformance profile, metadata, provenance, embedded resources, and a validation record. National Archives guidance and veraPDF documentation should inform the process; do not infer compliance from a compression result. Preserve the original and record every transformation.1, 2
| Requirement | Question | Evidence |
|---|---|---|
| PDF/A profile | Which conformance level is required? | Validation report from the approved validator |
| Provenance and metadata | What must identify the record? | Source, transformation, and metadata record |
Validate the archival candidate separately
- Capture the repository's profile and submission requirements.
- Preserve the source and make a working candidate.
- Run the approved PDF/A or archival validator.
- Store the candidate, report, and provenance record together.
FAQ
Can I compress a PDF before archiving it?
Possibly, but only within the repository's approved preservation workflow. Validate the resulting candidate and record the transformation rather than assuming compression is harmless.
Does PDF/A always mean the file is archived correctly?
No. PDF/A conformance is one part of preservation. Metadata, provenance, storage, access, and repository policy also matter.
Sources
- veraPDF — Validation documentationofficial technical documentationSource reviewed:
- U.S. National Archives — Scanned Images of Textual Recordsgovernment technical guidanceSource reviewed: