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Re: Correct PDF/UA tagging structure for Indexes ?

for

From: Duff Johnson
Date: Jan 2, 2024 10:54AM

Hi Rick,

Thanks for the excellent questions!

I can provide some partial answers…

Regarding illustrative examples… in fact, the PDF Association's PDF Accessibility Liaison Working Group (LWG) launched a project to develop Techniques for Accessible PDF several years ago. The results of that project are previewed in this recent post:

https://pdfa.org/pdf-techniques-for-accessibility-a-new-model/

As you can see from the example provided, each Technique will include a PDF file demonstrating the technique in an “atomic” fashion to ensure clarity for both developers and end users.

The initial release of the group's so-called “Fundamental” Techniques is slated for later this month, with subsequent releases of additional “use case” examples to cover the semantic constructs that can occur in documents (tables, lists, etc, etc.).

As to the Index element specifically; the PDF specification is… ah… deliberately vague regarding the substructure of this structure element, in part because there's no such thing as 'the right way” to design an index… sometimes a simple list is appropriate, sometimes a bunch of lists, or nested lists, or table(s)… and there can be complications such as references to page-ranges.

That said, the PDF Association is soon to publish some new guidance in this area as a usage specification for tagged PDF in the PDF 2.0 context. The same requirements will also be included in the forthcoming PDF/UA-2. However, this guidance - while improving on that provided in PDF/UA-1 - won't offer all that you seek, as it is constrained by the necessary flexibility in the concept of “Index”. Developing canonically-correct examples of various styles of indices is precisely the work of the PDF Accessibility LWG. Come and help us get it done! :-)

Regarding fora for the discussion...

- I note that your company is already a Full member of the PDF Association (:-) and therefore has comprehensive access to all our members-only and LWG communities. You are more than welcome to join - for example - the PDF Accessibility LWG mentioned above and pose your questions, thus helping that group to develop example(s) of valid structures for Index content. Just login to the Member Area and go from there.

- The PDF Accessibility LWG - like all our Liaison Working Groups - is open to non-members who wish to contribute to projects such as Techniques development.

- Although we maintain several LinkedIn Groups dedicated to accessible PDF they have real limitations, and thus, we are actively considering some other type of forum for non-members. Hopefully I’ll have more news on this soon.

Thanks,

Duff Johnson

PDF Association, CEO
https://www.pdfa.org


> On Jan 2, 2024, at 12:05, Rick Davies via WebAIM-Forum < <EMAIL REMOVED> > wrote:
>
> Hello all,
>
> The estimable PDF Association has explanatory technical notes about how to conform to the
> PDF/UA standard. But those documents don't contain many illustrative examples and *no*
> illustrative examples about index markup--I guess they are not intended as cookbooks. The
> PDF Association also has several helpful example PDF/UA documents contributed by third
> parties--none of them contain indexes. After weeks of searching, I have not been able to
> find much or anything about PDF/UA index markup: no credibly tagged PDF/UA documents with
> indexes. The old Adobe PDF 1.6 document has a magnificent index, but no Index tagging.
> All the successor ISO PDF standard documents don't have any indexes 🙁.
>
> So I'm wondering a) if anyone knows where such examples may be found and b) how should a
> developer of a PDF output generator produce PDF/UA tagging for the following index structure?
> (The objective is that the PDF output-generator should create 'born accessible' PDFs,
> without the need for any remediation.)
>
> Rough and ready index example:
> > Index
> >
> ___
> A
> ___
>
> Artichokes 3, 15-38, 133
> cooking 16, 31, 32, 33
> in oil 31, 32
> in butter 31, 33
> growing
> hyponetically 24-27
> au naturelle 20-21
>
> Artischocken 66, 70, 90
> Kochen 80, 81, 92
>
> Avocados 55-58, 133
>
> ...
> ___
> B
> ___
>
> Bananas 65, 65
>
> >
> In the above 'A' and 'B' are index sub-headings, aka group titles. And the 'au naturelle',
> 'Artischocken' and 'Kochen' represent index entries in different languages.
>
> What would be the complete PDF/UA tagging required to express the above index structure,
> including page links? Is there a tagging structure for the above that would be compatible
> with all of UA-1, UA-2, PDF 1.7 and PDF 2 ?
>
> OTOH this mailing list "is for anyone interested in discussing *web* accessibility issues" so
> perhaps the above question would be better asked somewhere else? The PDF Association does
> not seem to have a forum ...
>
> All suggestions and comments very gratefully received 🙂.
>
> Many thanks,
>
> Rick
>
> --
> > Rick Davies, Technical Sales Manager
> Palm Gate, Kenmare,
> Co. Kerry, Irelandwww.miramo.com
> > > > >