PDF Versions and Conformance

The serializer auto-detects the minimum PDF header version required by the features used. Conformance profiles add stricter validation and metadata.

Auto-detected versions

Feature	Minimum version
Baseline	1.4
objectStreams: true	1.5
AES-128 encryption	1.6
AES-256 (R=5)	1.7
Attachments / signatures / pdfua-1	1.7
AES-256 (R=6)	2.0

mergeDocuments, appendPages, extractPages, and splitDocument carry the maximum source version forward so output never declares a lower version than its inputs.

Conformance profiles

Set conformance to enforce PDF/A or PDF/UA invariants at serialization time:

const archive = createDocument({ title: "Archive", conformance: "pdfa-1b" });
const accessible = createDocument({ conformance: "pdfua-1", tagged: true, language: "en-US" });

Profile	Notes
pdfa-1b	Static archival. Fonts must be embedded. ICC output intent required.
pdfua-1	Accessibility. Tags, language, alt text, embedded fonts required.

When a profile is set, missing inputs throw PdfEngineError instead of silently producing non-conformant output. Use validateCompliance() to collect all warnings/errors first:

const issues = doc.validateCompliance();
for (const issue of issues) {
  console.log(issue.severity, issue.message);
}

ICC output intents

PDF/A documents require an output intent. Provide an ICC profile and identifier:

const doc = createDocument({
  conformance: "pdfa-1b",
  outputIntent: {
    profile: cmykIccBytes,
    outputConditionIdentifier: "Press CMYK",
    alternate: "DeviceCMYK",
    channels: 4
  }
});

For RGB workflows, omit alternate/channels to use the bundled sRGB profile.

PDF 2.0 considerations

PDF 2.0 changes structure namespace handling and AES-256 (R=6) key derivation. The library tracks PDF 2.0 namespacing for tagged elements and emits 2.0 headers automatically when AES-256-R6 or PDF 2.0-only features are used. validatePdf2Conformance(bytes) runs additional namespace and structure checks for 2.0 output.

veraPDF for standards-level checks

validateCompliance() is intentionally lightweight. For full PDF/A and PDF/UA validation, install veraPDF:

npm run validate:pdf -- output.pdf
npm run validate:pdf -- output.pdf -- --flavour 1b
VERAPDF_BIN=/opt/verapdf/verapdf npm run validate:pdf -- output.pdf