Dear All, I am starting a new thread as requested. I can confirm that
the following should work with current latest (from yesterday, LuaMetaTeX 2.11.07 20250427 + ConTeXt LMTX 2025.04.28 14:29):
\enabledirectives [backend.usetags=testing] \setuptagging[state=start] \setupstructure[state=start] \setupbackend [format=PDF/A-3a] \setupbackend[format=pdf/ua-1] \setupexternalfigures[location=default] \starttext \externalfigure[hacker][label={this is an image}]
\startparagraph a \stopparagraph \stoptext
produces a PDF that passes the accessibility check in the current Adobe Acrobat. In particular, it passes the alternate text checks. Hovering over the image shows the alternate text in Acrobat. However, VoiceOver (on the Mac) does not read the alternate text; it completely ignores the existence of the image. In Preview, no alternate text is shown or read. So it seems that the only benefit is that readers with vision can see an alternate text... I don’t have access to a Windows machine, so I cannot test what other screen readers can do with this document. Thanks, Matthias