ISO 16684
ISO 16684 is the ISO family of standards which defines XMP (eXtensible metadata platform) for XML-based metadata. XMP is widely used across PDF and other file formats, and is mandated by many ISO PDF subsets.
Additional information related to ISO 16684 can be found in the PDF Association’s Technical Resources.
ISO 16684-1 XMP Data model
ISO 16684-1:2019 Graphic technology — Extensible metadata platform (XMP) — Part 1: Data model, serialization and core properties defines the two essential components of XMP metadata:
- Data model: The data model is the most fundamental aspect. This is an abstract model that defines the forms of XMP metadata items, essentially the structure of statements that XMP can make about resources.
- Serialization: The serialization of XMP defines how an instance of the XMP data model can be recorded as XML.
In addition, this document defines a collection of core properties, which are XMP metadata items that can be applied across a broad range of file formats and domains of usage. The embedding of XMP packets in specific file formats and domain-specific XMP properties are beyond the scope of this document.
XMP Part 1 was first published by ISO in 2012 and was based on previous Adobe documentation.
ISO 16684-2 XMP schemas using RelaxNG
ISO 16684-2:2014 Graphic technology — Extensible metadata platform (XMP) — Part 2: Description of XMP schemas using RELAX NG specifies the use of RELAX NG to describe serialized XMP metadata. This applies to how conforming schemas can use the features of RELAX NG.
ISO 16684-3 JSON-LD serialization of XMP
ISO 16684-3:2021 Graphic technology — Extensible metadata platform (XMP) specification — Part 3: JSON-LD serialization of XMP defines how the XMP data model can be serialized to JSON-LD.
ISO 16684-4 Use of XMP for semantic units
ISO 16684-4:2024 Graphic technology – Extensible metadata platform (XMP) specification — Part 4: Use of XMP for semantic units introduces the concept of the semantic unit (SU), defines the target resource in an SU and provides requirements and guidance on XMP serialization syntaxes for SU.