Overview
ISO 16684-3:2021 - Graphic technology - Extensible Metadata Platform (XMP) specification - Part 3: JSON‑LD serialization of XMP - defines how the XMP data model is serialized to JSON‑LD. The standard provides rules and examples for converting XMP (traditionally serialized as RDF/XML) into a JSON‑based Linked Data form so XMP metadata can be used in web, semantic‑web and JSON‑centric workflows.
Keywords: ISO 16684-3:2021, XMP, JSON‑LD, metadata serialization, RDF, Linked Data, @context, @id, @type, namespaces, IRI.
Key topics and requirements
- Mandatory @context: All JSON‑LD serializations of XMP must include an @context mapping namespace prefixes to IRIs (namespace prefix serialization).
- Property naming: XMP property names are expressed as compact IRIs (prefix:suffix) using terms defined in the @context.
- Resource identity: The XMP rdf:about (AboutURI) maps to JSON‑LD @id. If no AboutURI exists, an empty @id must be present.
- Type handling: Node and value typing uses JSON‑LD @type (or, where appropriate, rdf:type) to represent rdf:type and typed nodes from RDF/XML.
- Value forms: The standard formalizes serialization for the three XMP value forms - simple, structure, and array - including array kinds: unordered, ordered, and alternative. JSON‑LD defaults arrays to unordered.
- Literal and URI values: Simple literal values serialize as native JSON values; URI values serialize as objects with an @id key.
- Qualifiers and nested structures: Rules cover qualifiers, structure fields, nested arrays and complex modeling consistent with ISO 16684‑1.
- Normative references: Relies on JSON‑LD 1.1 (W3C) and BCP‑47 language tags for internationalized strings; Unicode (ISO/IEC 10646) for text.
Practical applications
- Enable interoperability between image/asset metadata systems and web/JSON ecosystems.
- Publish XMP metadata as Linked Data for search engines, knowledge graphs and semantic web consumption.
- Facilitate metadata exchange in DAM (Digital Asset Management), publishing, archives, libraries, and media workflows where JSON is preferred.
- Support modern web APIs that ingest or expose asset metadata without XML/RDF processing.
Who should use this standard
- Software developers and architects implementing XMP exporters/importers
- Digital asset managers, photographers, publishers, and imaging software vendors
- Metadata architects, archivists and library technologists integrating XMP with web/Linked Data
- Organizations migrating legacy RDF/XML XMP to JSON/JSON‑LD ecosystems
Related standards
- ISO 16684‑1 (XMP data model and RDF/XML serialization)
- JSON‑LD 1.1 (W3C Recommendation)
- BCP‑47 (language tags)
- ISO/IEC 10646 (Unicode character set)
This part of ISO 16684 ensures consistent, standards‑based conversion of XMP metadata into JSON‑LD for reliable, interoperable use across web and application environments.