Optimize PDF Documents for Long-Term Preservation

Standardize PDFs for a Long-Term Records Program

PDF supports a broad range of interactive, multimedia, encrypted, and externally dependent features. That flexibility is valuable for everyday documents, but a preservation program benefits from narrower rules that make each file more self-contained and predictable. PDF/A applies those rules through the ISO 19005 family of standards.

The pdfRest Convert to PDF/A API Tool transforms standard PDFs into supported archival variants using Adobe PDF technology. It can embed required font information, standardize color behavior, remove or transform features that conflict with the selected conformance level, and produce a PDF/A file suitable for the organization's retention workflow.

PDF/A supports the document layer of preservation. Records teams can combine it with descriptive metadata, retention schedules, access controls, checksums, redundant storage, and managed migration policies to create a complete long-term strategy.

Select the PDF/A Level Required by the Archive

pdfRest supports PDF/A-1b, PDF/A-2b, PDF/A-2u, PDF/A-3b, and PDF/A-3u. The archive's policy or receiving authority should determine the target rather than applying one version to every collection.

• PDF/A-1b focuses on reproducible visual appearance under the original PDF/A specification.
• PDF/A-2b supports newer PDF features while retaining basic visual conformance.
• PDF/A-2u adds requirements for Unicode mappings, which support reliable text interpretation.
• PDF/A-3b permits non-PDF attachments such as XML, CSV, or source data within the archival PDF.
• PDF/A-3u combines attachment support with the Unicode-mapping requirement.

For example, a public-records repository may select PDF/A-2u for searchable born-digital documents, while an e-invoice archive may require PDF/A-3 so the human-readable invoice and structured XML remain in one package. pdfRest exposes the version as output_type, allowing the application to route each record class to its approved target.

Handle Difficult Source Content Within Policy

Some PDFs contain features that prevent a direct standards conversion. The rasterize_if_errors_encountered option provides a fallback that preserves the visual page when the normal conversion path encounters incompatible content. Archives that prioritize visual preservation can enable this behavior as part of their defined intake policy.

The request can upload a file directly or use the resource ID returned by an earlier pdfRest operation. Resource-ID chaining is useful when source documents are first generated from Office, image, email, HTML, or structured-text formats and then standardized as PDF/A without intermediate downloads.

Add Automated Conformance Validation

The Query PDF API Tool uses veraPDF to return PDF/A conformance as a straightforward pdfa result. An archive can evaluate incoming files, send only non-conformant PDFs through conversion, and query the resulting output before recording it in the repository. This creates a scalable intake decision and a machine-readable conformance record.

The cURL request below converts a PDF to PDF/A-3b and enables the visual-preservation fallback.

Convert a PDF to PDF/A-3b Code Example   |   Load this into API Lab↗

# By default, this request uses the US-based API service.
API_URL="https://api.pdfrest.com"

# For the EU-based service, use:
# API_URL="https://eu-api.pdfrest.com"

curl -X POST "$API_URL/pdfa" \
  -H "Accept: application/json" \
  -H "Content-Type: multipart/form-data" \
  -H "Api-Key: xxxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" \
  -F "file=@/path/to/document.pdf" \
  -F "output=archival_document" \
  -F "output_type=PDF/A-3b" \
  -F "rasterize_if_errors_encountered=on"

For the complete conditional process, see Detect and Repair Non-Conformant PDF/A Documents. Use API Lab to configure a target and review the Convert to PDF/A and Query PDF API references for current fields.

Convert to PDF/A