On 2025-05-01 06:32, Pablo Rodriguez via ntg-context wrote:

On 5/1/25 00:02, Rik Kabel wrote:

[...]
I took the route described in the mailing list at https://www.mail-
archive.com/ntg-context@ntg.nl/msg64956.html and inserted it
successfully as follows:

|\setupbackend[format={PDF/UA-1}] \setuptagging[state=start]
\enabledirectives[backend.usetags=crap] \startluacode
lpdf.injectxmpinfo("xml://rdf:RDF","<rdf:Description rdf:about=''
xmlns:tdm='http://www.w3.org/ns/tdmrep/'><tdm:reservation>1</
tdm:reservation></rdf:Description>",false) \stopluacode |

Many thanks for the code, Rik.

Just in case anyone intends to use any form of TDM reservation, it seems
that it might break PDF/A validation.

I haven’t tested it, but there is a warning:
https://www.w3.org/community/reports/tdmrep/CG-FINAL-tdmrep-20240510/#issue-container-generatedID-6.

Just in case it helps,

Pablo

Indeed, it does fail VeraPDF tests for PDF/A-3A if no effort is made to accept the XMP, but it passes VeraPDF testing as PDF/UA-1.

At https://pdfa.org/resource/iso-14289-pdfua/, one can read:

> PDF/UA-1 documents may also conform to PDF/A-2 (ISO 19005-2) or PDF/A-3 (ISO 19005-3). In such cases, these PDF/A standards require the inclusion of XMP Extension Schema for custom XMP metadata not defined in the relevant ISO 19005 part. The PDF Association provides free XMP Extension Schema templates for PDF/UA-1, other ISO PDF subset standards, and PDF Declarations.

The phrase "free XMP Extension Schema templates" links to https://pdfa.org/resource/xmp-extension-schema-templates/, where we read, inter alia:

> 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.

I have not succeeded in integrating the provided extension schema.