XMP Extension Schema Templates
The PDF 1.x based PDF/A standards (PDF/A-1 (ISO 19005-1), PDF/A-2 (ISO 19005-2), and PDF/A-3 (ISO 19005-3)) all require the use of XMP Extension Schema whenever additional metadata not defined by the appropriate ISO 19005 part is included in the XMP Metadata stream. Thus, XMP Extension Schemas must be included for multi-conformant documents when additionally complying with other ISO PDF subset standards that also mandate the use of XMP.
This page provides resources for free XMP Extension Schema templates that support compliance with other ISO standards and specifications utilizing XMP. For efficiency, these templates should be edited to include only the necessary portions.
ISO-standardized PDF subsets template
This download link (XML) is a free comprehensive XMP Extension Schema template (in “PDF/A extension schema container schema” syntax appropriate for inclusion in PDF/A-1, PDF/A-2, and PDF/A-3 files) that supports the following ISO PDF subset standards:
- PDF/A (ISO 19005) – parts 1-3 only. PDF/A-4 is for use with PDF 2.0 only and is not supported by this template.
- PDF/UA (ISO 14289) – all parts. PDF/UA-2 is for use with PDF 2.0 only and is thus compatible only with PDF/A-4 which does not mandate using XMP Extension Schemas.
- PDF/X (ISO 15930) – all parts. PDF/X-6 is for use with PDF 2.0 only and is thus compatible only with PDF/A-4 which does not mandate using XMP Extension Schemas.
- PDF/VT (ISO 16612-2) – all parts. PDF/VT-3 is for use with PDF 2.0 only and is thus compatible only with PDF/A-4 which does not mandate using XMP Extension Schemas.
PDF/A-4 (ISO 19005-4) supports PDF 2.0 and does not mandate using XMP Extension Schema but instead recommends their inclusion (via a “should” statement) as an Associated File with an AFRelationship value of Schema. Such schemas must be in RELAX-NG (as per ISO 16684-2 Graphic technology — Extensible metadata platform (XMP) — Part 2: Description of XMP schemas using RELAX NG) and thus will have a Subtype of application/xml or text/xml. See clause 6.7 in ISO 19005-4.
PDF Declarations template
The XMP Extension Schema for PDF Declarations is located as the embedded file “A Extension Schema.xmp” in the PDF Declarations Specification (PDF) document. It can be included without modification.
W3C’s TDMRep
The W3C’s Final Community Group Report on the “TDM Reservation Protocol (TDMRep)” defines XMP metadata for PDF files to express the reservation of rights relative to text & data mining (TDM) applied to lawfully accessible content and to ease the discovery of TDM licensing policies associated with such content. The PDF Association also wishes to clarify that the TDMRep properties in the document catalog XMP metadata apply to all pages and all resources in a PDF file.
This W3C report incorrectly notes that PDF/A validators will raise errors if TDMRep properties are present in the XMP metadata section of PDF documents. As clearly stated in ISO 19005-1 (PDF/A-1), ISO 19005-2 (PDF/A-2), and ISO 19005 (PDF/A-3) appropriate XMP Extension Schema must always be included. This download link (XML) is a free XMP Extension Schema template in “PDF/A extension schema container schema” syntax appropriate for inclusion in PDF/A-1, PDF/A-2, and PDF/A-3 files that supports TDMRep.
ISO 19005-4 (PDF/A-4) only recommends (but does not require!) that a schema in RELAX-NG format (conforming to ISO 16684-2) is included. Thus PDF/A-4 (PDF 2.0) documents will not fail PDF/A-4 validation if TDMRep XMP metadata is included without a schema.
