veraPDF fails to reject PDF 2.0 files with declared PDF/UA-1 conformance

[petervwyatt]

The latest veraPDF/rest Docker container does not fail a PDF 2.0 file that declares PDF/UA-1 conformance. ISO 14289-1 states that PDF/UA-1 only applies to PDF 1.x files. PDF 2.0 files need to use PDF/UA-2.

Here is a sample PDF 2.0 file that accidentally declares dual conformance to both PDF/A-4f (which passes) and PDF/UA-1 that should get failed because it is PDF 2.0. I manually selected "PDF/UA-1" for the check:

pdfa-4f+ua+odf.pdf

(This incorrect PDF was generated by LibreOffice-Dev branch as a result of my issue 160196 which I am testing.)

[bdoubrov]

@petervwyatt thanks for bringing this up. I see that ISO 14289-1, 6.1 says:

The version number of a file may be any value from 1.0 to 1.7, and the value shall not be used in determining whether a file is in conformance with this part of ISO 14289.

Applied to your example, we clearly get two conflicting requirements:

1. The version number of a file may be any value from 1.0 to 1.7
2. The value shall not be used in determining whether a file is in conformance with this part of ISO 14289.

The second negates the first one. Or should it be read differently?

[petervwyatt]

@bdoubrov I interpret those words differently and don't see any conflict: the "conformance" statement is about how to know if a file is declaring itself as "conforming to PDF/UA" and this is done solely on the XMP metadata meaning that processors/AT don't need to check all the requirements of the PDF DOM data in order to determine if should be considered PDF/UA-1. And for processors (non-validators) that is a single simple step - check the XMP --> PDF/UA-1 then can blindly go ahead and treat as PDF/UA-1.

Does that make sense?

PS. Of course a robust processor may still decide to do checks at runtime as it processes a self-declared PDF/UA-1 file, but that is good programming not an ISO requirement.

[bdoubrov]

OK, so the requirement for PDF/UA-1 documents to have version 1.0-1.7 comes not from this conformance clause, but from the fact that PDF/UA-1 is based on ISO 32000-1, and the latter declares only 1.0-1.7 as "known" versions?

I'm trying to speak it up carefully, as the tests of other PDF/UA validators on your sample file give different results. And we'd like to have a definitive answer in case of further questions.

[petervwyatt]

@bdoubrov - yes, that's my take since ISO 32000-1:2008 7.5.2 clearly states BOTH a file format requirement and a "conforming reader" requirement to support only 1.x. So these both get inherited via the reference.

So definitely CANNOT have PDF/UA-1 files that are PDF 2.0. That is "reserved" for PDF/UA-2.