content of tiling patterns is exempt for the requirement to have all elements tagged or marked as artifacts

[bdoubrov]

See veraPDF/verapdf-js-viewer#78 for the original issue.

The attached PDF/UA-1 contains a tiling pattern with content not tagged and not marked as artifacts.

The same issue has already been discussed in in the scope of PDF/UA-2, and it was agreed that the content of tiling patterns and glyphs in Type3 fonts is indeed not subject to the PDF/UA requirement to tag all graphical elements or mark them as artifacts.

Needs to be fixed in PDF/UA-1 case as well.

[mkl-public]

The same issue has already been discussed in in the scope of PDF/UA-2, and it was agreed that the content of tiling patterns and glyphs in Type3 fonts is indeed not subject to the PDF/UA requirement to tag all graphical elements or mark them as artifacts.

Just out of interest: Does that mean that a document with all content in a pattern can call itself PDF/UA even without tagging anything?

(Putting all content of a page into a page-sized pattern that then is used to fill the page is a well-known mechanism to make PDFs that prevent copy&paste when opened in most PDF viewers.)

[bdoubrov]

@mkl-public interesting question!

Tiling pattern is (kind of) a color. So, it is more important, which object is colored and what is the semantics of this object. So, if this is just a page size rectangle as in your example, the creator has to specify what is the semantics of this rectangle. It might well be a Figure with alt text or another Artifact.

In the test file of this particular issue there is a rectangle drawn using several tiling patterns, and this rectangle is marked as an Artifact.

[bdoubrov]

TEST-pdf.pdf

[bdoubrov]

Fixed in the latest dev build