---
title: Metadata Formats
description: The cataloging and interchange standards Preservated emits — Dublin Core, LIDO, CDWA-Lite, MARC21-slim, and CIDOC-CRM JSON-LD.
section: formats
order: 4
updated: 2026-07-11
verified: 2026-07-11
related: [formats, protocols/oai-pmh, protocols/linked-data]
features: [metadata-export]
---

# Metadata Formats

Preservated emits artifact records in several established metadata standards, so aggregators, discovery services, and other collection-management tools can consume them without a custom mapping. Five of these are available through [OAI-PMH harvesting](/developers/en-US/protocols/oai-pmh) (and, for bulk offline use, as an XML option in [Export Packages](/developers/en-US/formats/export-packages)); a sixth is a linked-data format available per artifact.

## Dublin Core (`oai_dc`, `oai_qdc`)

Simple and Qualified Dublin Core are the baseline interchange formats most OAI-PMH harvesters expect.

- `oai_dc` — Simple Dublin Core (namespace `http://www.openarchives.org/OAI/2.0/oai_dc/`): the 15 unqualified `dc:` elements.
- `oai_qdc` — Qualified Dublin Core (namespace `http://epubs.cclrc.ac.uk/xmlns/qdc/`): adds refined `dcterms:` elements (for example a structured `dcterms:created` date, `dcterms:medium`, `dcterms:rightsHolder`) that plain DC has to drop. Controlled values that carry a known authority also emit `valueURI`/`authority` attributes, so a harvester can bind to the same authority term instead of treating it as a bare string.

## LIDO 1.0

`lido` (namespace `http://www.lido-schema.org/`) is an object-level museum-description standard aimed at aggregators built for museum collections rather than library or archival records. Controlled terms round-trip their source authority as a `lido:conceptID` attribute.

## CDWA-Lite 1.1

`cdwalite` (namespace `http://www.getty.edu/CDWA/CDWALite`) is the Getty object-description standard used by ARTstor-style aggregators. Controlled terms carry their authority as `termsource`/`termsourceID` attributes rather than a dedicated element.

## MARC21-slim

`marc21` (namespace `http://www.loc.gov/MARC21/slim`) is MARCXML, the library bibliographic interchange format used by WorldCat-style aggregators. Controlled access points carry their authority as MARC subfields `$0` (the authority URI) and `$2` (the source code).

## CIDOC-CRM linked data (JSON-LD)

Every public artifact also has a dedicated linked-data representation — a JSON-LD document using the CIDOC-CRM ontology (namespace `http://www.cidoc-crm.org/cidoc-crm/`), the event-centric standard used across museum and cultural-heritage linked-data projects. The artifact is modeled as an **E22 Human-Made Object**; its creation details (date, creators, place, technique) hang off a single **E12 Production** event; classified concepts map to **E55 Type** or **E57 Material** nodes. A handful of Dublin Core Terms literals (title, description, type, rights) ride alongside the CRM structure for consumers that don't want to walk the full event graph.

This isn't harvested through OAI-PMH — it's fetched per artifact. See [Linked Data](/developers/en-US/protocols/linked-data) for the request shape and the full class/property mapping.

## Choosing a format

- Building a generic aggregator or don't have a strong preference → **Qualified Dublin Core** (richest of the DC-family formats).
- Building for a museum-specific aggregator → **LIDO**.
- Targeting a Getty/ARTstor-style pipeline → **CDWA-Lite**.
- Targeting a library/WorldCat-style pipeline → **MARC21-slim**.
- Need linked, dereferenceable entities (shared identity across institutions for the same authority-linked person, place, or concept) → **CIDOC-CRM JSON-LD**.

Across every format, a controlled value's source authority (its scheme and URI) is carried through exactly as the institution recorded it — Preservated never invents or resolves authority data on export.