I saw that there is a typo in the example from contextgarden.
This one is correct:

\setupbackend[
format={pdf/a-1b:2005},
profile={default_cmyk.icc,default_rgb.icc,default_gray.icc},
intent=Coated FOGRA39 (ISO 12647-2:2004),
level=0]

\setupstructure[state=start,method=auto]
\setupbackend[export=yes]

\setupexternalfigures[location=default]
\starttext
   \startPDFalternativetext{this is a cow}
       \externalfigure[cow]
   \stopPDFalternativetext
\stoptext


But again, Acrobat Reader > Document Properties > Tagged PDF > No

Steffen



> Am 06.02.2025 um 13:06 schrieb Steffen Wolfrum <context@st.estfiles.de>:
> 
> When running the test with an older (2022.07.06 21:42) LMTX
> and opening the PDF with Acrobat Reader, checking the Document Properties “Tagged PDF?” it says “Yes”!
> 
> Steffen
> 
> 
>> Am 06.02.2025 um 12:56 schrieb Florent Michel <florent.m42@gmail.com <mailto:florent.m42@gmail.com>>:
>> 
>> No. I tested it (and added also the backend stuff) ...
>> \setupbackend[
>> format={pdf/a-1b:2005},
>> profile={default_cmyk.icc,default_rgb.icc,default_gray.icc},
>> intent=Coated FOGRA39 (ISO 12647-2:2004),
>> level=0]
>> \setupstructure[state=start,method=auto]
>> \setupbackend[export=yes]
>> \setupexternalfigures[location=default]
>> \starttext
>> \pdfalternativetext{\externalfigure[cow]}
>>     {alternate description}
>> \stopPDFalternativetext
>> \stoptext
>> … but when opening the PDF with Acrobat Reader and checking the Document Properties “Tagged PDF?” it says “No”.
>> (Even though it is recognised as PDF/A)
>> 
>> Thanks for having tried! I unfortunately know nothing about how Acrobat Readers checks for a tagged PDF, so I'll refrain from trying to propose solutions - which would likely not work. 
>> 
>> Cheers,
>> Florent
>> 
>> Le jeu. 6 févr. 2025 à 11:23, Steffen Wolfrum <context@st.estfiles.de <mailto:context@st.estfiles.de>> a écrit :
>> No. I tested it (and added also the backend stuff) ...
>> 
>> \setupbackend[
>> format={pdf/a-1b:2005},
>> profile={default_cmyk.icc,default_rgb.icc,default_gray.icc},
>> intent=Coated FOGRA39 (ISO 12647-2:2004),
>> level=0]
>> \setupstructure[state=start,method=auto]
>> \setupbackend[export=yes]
>> 
>> \setupexternalfigures[location=default]
>> \starttext
>> \pdfalternativetext{\externalfigure[cow]}
>>     {alternate description}
>> \stopPDFalternativetext
>> \stoptext
>> 
>> … but when opening the PDF with Acrobat Reader and checking the Document Properties “Tagged PDF?” it says “No”.
>> (Even though it is recognised as PDF/A)
>> 
>> Steffen
>> 
>> 
>>> Am 04.02.2025 um 16:40 schrieb Florent Michel <florent.m42@gmail.com <mailto:florent.m42@gmail.com>>:
>>> 
>>> Hi, 
>>> 
>>> It seems that the accessibility page has moved here: https://wiki.contextgarden.net/Input_and_compilation/Accessibility <https://wiki.contextgarden.net/Input_and_compilation/Accessibility> .
>>> Maybe the last example is suitable? 
>>> 
>>> (It seems to correctly embed the alt text in the pdf; this can be checked by using the `--nocompression` flag and opening the resulting pdf with a text editor. Not sure how to have the alt text in the exported html, though; I'm sure others will be able to advise on that better than I could.)
>>> 
>>> Best,
>>> Florent
>>> 
>>> 
>>> Le mar. 4 févr. 2025 à 14:29, Steffen Wolfrum <context@st.estfiles.de <mailto:context@st.estfiles.de>> a écrit :
>>> Hi,
>>> 
>>> today my publishers ask for an example of how ConTeXt deals with accessibility.
>>> 
>>> I send them a PDF with
>>> 
>>> \setupbackend[export=yes]
>>> \setupstructure[state=start,method=auto]
>>> 
>>> What they needed was like
>>> <img src="example.jpg" alt="Example text">
>>> 
>>> What is the equivalent for this with ConTeXt?
>>> Contextgarden ( https://contextgarden.net/Accessibility <https://contextgarden.net/Accessibility>) is empty...
>>> 
>>> Yours, Steffen
>>> 
>>> 
>>> 
>>> > Am 23.09.2024 um 17:09 schrieb Hans Hagen via ntg-context <ntg-context@ntg.nl <mailto:ntg-context@ntg.nl>>:
>>> > 
>>> > On 9/23/2024 8:02 AM, Pablo Rodriguez via ntg-context wrote:
>>> >> On 9/22/24 21:58, Hans Hagen via ntg-context wrote:
>>> >>> On 9/22/2024 2:43 PM, Pablo Rodriguez via ntg-context wrote:
>>> >>> 
>>> >>>> It would be great to have synonyms added the /E information by default.
>>> >>>> I think this may be a requirement for text-to-speech conversions.
>>> >>> 
>>> >>> even more crap .. let's wait till abbreviations are completely forbiddeb
>>> >>> (and also units and such )
>>> >> From what I see, /E may be helpful (similar to /ActualText).
>>> > 
>>> > Imo it's useless:
>>> > 
>>> > (1) normally when a new abbreviation is intriduced one has the expanded meaning after it
>>> > (2) after that it is suposed to be known
>>> > (3) if one jumps into a document in the middle one cannot expect it to be repeated every time
>>> > (4) if that *is* expoected there is no need to use abbreviations at all
>>> > (5) so, why should a 'read out' document have all abbreviations with an expanded meaning and a typeset text not
>>> > 
>>> >> For me, the real problem with accessibility (and penalties for
>>> >> non-accessible documents) is that it will force all documents to be
>>> >> machine-readable (so we have to feed AI with all our public documents,
>>> >> whether we like it or not).
>>> > 
>>> > i assume that such a machine learning or pattern recognotion app can quite well figure out that it's an abbreviation
>>> > 
>>> >> I mean, no such as "\enabledirectives[backend.pdf.nounicode=❌]" allowed.
>>> > 
>>> > well, everything is allowed ... after all why do we typeset and visualize otherwise ... it depends on the audience
>>> > 
>>> > one can always generate multiple versions, one with two times the number of pages and all expanded
>>> > 
>>> > Hans
>>> > 
>>> > 
>>> > 
>>> > -----------------------------------------------------------------
>>> >                                         Hans Hagen | PRAGMA ADE
>>> >             Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
>>> >      tel: 038 477 53 69 | www.pragma-ade.nl <http://www.pragma-ade.nl/> | www.pragma-pod.nl <http://www.pragma-pod.nl/>
>>> > -----------------------------------------------------------------
>>> > ___________________________________________________________________________________
>>> > If your question is of interest to others as well, please add an entry to the Wiki!
>>> > 
>>> > maillist : ntg-context@ntg.nl <mailto:ntg-context@ntg.nl> / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl <https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl>
>>> > webpage  : https://www.pragma-ade.nl <https://www.pragma-ade.nl/> / https://context.aanhet.net <https://context.aanhet.net/> (mirror)
>>> > archive  : https://github.com/contextgarden/context <https://github.com/contextgarden/context>
>>> > wiki     : https://wiki.contextgarden.net <https://wiki.contextgarden.net/>
>>> > ___________________________________________________________________________________
>>> 
>>> ___________________________________________________________________________________
>>> If your question is of interest to others as well, please add an entry to the Wiki!
>>> 
>>> maillist : ntg-context@ntg.nl <mailto:ntg-context@ntg.nl> / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl <https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl>
>>> webpage  : https://www.pragma-ade.nl <https://www.pragma-ade.nl/> / https://context.aanhet.net <https://context.aanhet.net/> (mirror)
>>> archive  : https://github.com/contextgarden/context <https://github.com/contextgarden/context>
>>> wiki     : https://wiki.contextgarden.net <https://wiki.contextgarden.net/>
>>> ___________________________________________________________________________________
>>> ___________________________________________________________________________________
>>> If your question is of interest to others as well, please add an entry to the Wiki!
>>> 
>>> maillist : ntg-context@ntg.nl <mailto:ntg-context@ntg.nl> / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl <https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl>
>>> webpage  : https://www.pragma-ade.nl <https://www.pragma-ade.nl/> / https://context.aanhet.net <https://context.aanhet.net/> (mirror)
>>> archive  : https://github.com/contextgarden/context <https://github.com/contextgarden/context>
>>> wiki     : https://wiki.contextgarden.net <https://wiki.contextgarden.net/>
>>> ___________________________________________________________________________________
>> 
>> ___________________________________________________________________________________
>> If your question is of interest to others as well, please add an entry to the Wiki!
>> 
>> maillist : ntg-context@ntg.nl <mailto:ntg-context@ntg.nl> / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl <https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl>
>> webpage  : https://www.pragma-ade.nl <https://www.pragma-ade.nl/> / https://context.aanhet.net <https://context.aanhet.net/> (mirror)
>> archive  : https://github.com/contextgarden/context <https://github.com/contextgarden/context>
>> wiki     : https://wiki.contextgarden.net <https://wiki.contextgarden.net/>
>> ___________________________________________________________________________________
>> ___________________________________________________________________________________
>> If your question is of interest to others as well, please add an entry to the Wiki!
>> 
>> maillist : ntg-context@ntg.nl <mailto:ntg-context@ntg.nl> / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl <https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl>
>> webpage  : https://www.pragma-ade.nl <https://www.pragma-ade.nl/> / https://context.aanhet.net <https://context.aanhet.net/> (mirror)
>> archive  : https://github.com/contextgarden/context <https://github.com/contextgarden/context>
>> wiki     : https://wiki.contextgarden.net <https://wiki.contextgarden.net/>
>> ___________________________________________________________________________________
> 
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
> 
> maillist : ntg-context@ntg.nl / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl
> webpage  : https://www.pragma-ade.nl / https://context.aanhet.net (mirror)
> archive  : https://github.com/contextgarden/context
> wiki     : https://wiki.contextgarden.net
> ___________________________________________________________________________________