Compress PDF Archives Explained: Store Originals for Fidelity and Control Storage Cost

Compressing PDF archives involves creating a verified copy for regular retrieval, while retaining the original PDF as the audit record until its retention period ends. This approach helps maintain fidelity without increasing storage costs. When archiving a monthly student report, preserving the original PDF ensures fidelity by protecting the document's content, such as accommodation notes, attendance totals, charts, and final grades, which have visual relationships to their labels.

The decision to compress or store originals depends on the report's content and the reviewer's ability to inspect it later. A successful render is not always a guarantee of fidelity, as a pipeline may select the wrong output or validate only the existence of the object. To avoid this, maintain the original bytes and metadata together, as reproducibility is crucial.

The promotion process should have three states: rendered, verified, and archived. If verification fails, the original render remains available for diagnosis, and the derivative should not become the canonical object. A comparison function should be implemented to handle text, page, and visual checks specific to the report class.

Verification should be integrated into the same release path as the transformation, using a diverse set of samples, including awkward reports with long names, empty sections, non-Latin text, page breaks near totals, and large charts. The original and derivative sizes, verification outcome, and processing duration should be recorded for future reference.