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Jun 25, 2026

IPTC fallback in metadata exports

When you upload a TIFF, JPEG, or PSD that carries IPTC headers (the embedded metadata fields written by Photoshop, Lightroom, ExifTool, or most camera firmware), Heratio extracts the headers into the dam_iptc_metadata table the first time the digital object is processed. The three fields the export pipeline cares about are:

  • By-line - the photographer or creator name.
  • Copyright Notice - the rights statement.
  • Keywords - one or more subject terms.

Historically the export endpoints (OAI-PMH, Dublin Core, EAD) only looked at the ISAD(G) fields you filled in by hand. If the archival description had an empty Author / Rights / Keywords field but the file carried rich IPTC headers, harvesters saw an empty record.

From this release the exporters fall through to the IPTC value when the matching ISAD field is empty. The ISAD field always wins when it's set - the fallback never overrides anything you typed.

What changes for harvesters

Predicate Was (ISAD empty) Now (ISAD empty + IPTC present)
dc:creator element omitted IPTC By-line
dc:rights element omitted IPTC Copyright Notice
dc:subject element omitted one element per IPTC keyword
EAD <origination> element omitted IPTC By-line in <name> wrapper
EAD <userestrict> element omitted IPTC Copyright Notice in <p>
EAD <controlaccess><subject> element omitted one <subject> per keyword

How to spot a fallback

Every time the export pipeline falls through to an IPTC value it writes an info-level row to the System Log (Settings > Logs). Filter the log for IPTC fallback fired to see which descriptions are leaning on the extracted headers rather than your edited ISAD fields.

Once you see a row you usually want to do one of two things:

  1. Promote the IPTC value into ISAD. Open the description in the editor, copy the value from the IPTC tab into the canonical ISAD field (Author / Reproduction Conditions / Subject Access Points), and save. The next harvest emits the same value from the canonical source and the fallback goes quiet for that record.
  2. Override the IPTC value. Edit the ISAD field to whatever the correct authoritative value should be. The fallback only fires when the ISAD field is empty, so any non-empty value overrides the IPTC.

What gets emitted

The fallback feeds:

  • OAI-PMH oai_dc (the Identify-backed harvester surface).
  • OAI-PMH oai_ead and oai_ead3 crosswalks.
  • The Dublin Core / Dublin Core Qualified XML download from the Metadata Export dashboard.
  • The EAD 2002 / EAD 3 XML download.
  • The bulk CSV / EAD export jobs from the Export dashboard.

Edge cases

  • Multi-valued IPTC Keywords are stored as either a JSON array (the default ExifTool output) or a comma / semicolon / pipe-delimited string. Heratio accepts both formats.
  • Malformed IPTC blobs are silently ignored - a corrupt payload can never poison an OAI harvest.
  • Repositories with thousands of IPTC-only records will see one audit row per record per field per export pass. The resolver dedupes inside a single request, so a ListRecords page doesn't multiply rows.