[accessibility] Testing PDF tagging with a pdf generated using pdflatex

tammy stitz tstitz2 at gmail.com
Sat Mar 17 03:23:03 CET 2018

> Hi Ross:
> Thank you for your reply. I was getting an error when using pdfx because
> it clashes with the class file for theses and dissertations at my
> institution. I will try to solve the errors to resolve some of the font
> problems as you suggested.
> I didn't think of providing the code for the alt text. I think this would
> be an effective solution for those that know LaTeX. My partner is legally
> blind and is persuing a bachelors in mathematics. He doesn't know LaTeX, so
> this solution might not help readers like him. I think it might be best to
> make the alternate text close to how sceen readers read mathml. I couldn't
> figure out how to embed mathml into the PDF, but I think others have done
> this.
> I am not sure how close my alt text was to mathml, but what I wrote
> evolved somewhat from problems I found while writing them. For example, I
> use lowercase and uppercase letters to represent different variables, so I
> had to add the word uppercase for capital letters. Sometimes, it was
> unclear which matrix was inverted or when multiple variables were squared,
> etc. I had to use the term "quantity" to add clarity.
> I thought about tagging the matrix as tables; however, this would violate
> WCAG 1.3.1. The alt text I used was inspired by how tables are read. I
> specified the row but not the columns because I thought it might be too
> much. There is a fine line between helpful and annoying sometimes.
> It is hopeful that there will be a solution in the near future. My partner
> says the largest problem he has in school is PDFs that don't read properly.
> Sometimes it is due to instructors not using OCR, but many times it is
> untagged PDFs. Even the intellectual content of courses is easier that
> trying to figure how to read it.
> Best regards,
> Tammy
> From: Ross Moore
> Sent: Friday, March 16, 4:15 PM
> Subject: Re: [accessibility] Testing PDF tagging with a pdf generated
> usingpdflatex
> To: Stitz,Tammy A
> Cc: accessibility at tug.org
> Hello Tammy,
> On 16/03/2018, at 7:56, "Stitz,Tammy A" < tstitz at uakron.edu> wrote:
> Hello Everyone:
> I know that some of you wanted to know what happened when I tried to make
> a tagged PDF from a LaTeX generated PDF, so I am sending this email to the
> list. I tried a few packages when using pdflatex, but none seemed to make a
> structured, tagged PDF. The only software that I know that can add tags to
> a PDF is Adobe Acrobat.
> Yes, it does a reasonable job, but needs a lot of touching up afterwards.
> It is this manual post-processing that makes it unsuitable (yet) for an
> automated production system.
> But it is important that people like yourself try it out, to appreciate
> both the strengths and weaknesses of this approach — that is, adding tags
> after all the typesetting has been done.
> If you have used any other software, please let me know.
> What is really needed is for LaTeX processing to add tagging, according to
> the structure inherent in:
>  1. the author's LaTeX source
>  2. the chosen document-class
>  3. any loaded packages
> This is what I am working on, and have achieved with several significant
> examples, chock full of mathematical content. These will be part of my TUG
> presentation in Rio, later this year.
> They are not yet available online.
> I'll post again when they are.
> When Acrobat generated the tags, some strange things happened. (1) Some
> brackets and other large symbols like summations disappeared when I had
> Acrobat assign tags
> This happens with TeX's extension fonts, when there is no /ToUnicode
> resource.
> It helps to load  glyphtounicode.tex   to get mappings based upon the
> glyph name.
> This is just one of the things done when the  pdfx  package is loaded.
> The first step in developing methods to produce tagged PDF compliant with
> published ISO standards, is to first satisfy all requirements for PDF/A
> compliance. There is significant overlap.
> Ultimately you want to satisfy both  PDF/A-2a and PDF/UA-1.
> The  pdfx  package is vital to be able to achieve this.
> . I was thinking it might have to do with when a font was compressed. I
> adjusted what I used for commands (e.g. use bmatrix instead of
> \left\right). I was unable to find a pattern, but I thought it was worth
> mentioning.
> Many tags and much of the reading order needs corrected after Acrobat
> creates the tags.
> Precisely. It's too much work, and cannot result in anything close to what
> a fully-automated approach from LaTeX can achieve.
> If you have mostly text and simple equations, the screen reader JAWS reads
> it well. I used my thesis as a test case and it had many matrix equations,
> which are read awful by JAWS. The only solution that I could find was to
> add alternative text to each equation, which was very time consuming
> The big question here is  ‘What should that alternative text be?'
> Just reading the characters separately is not sufficient.
> How about the LaTeX source, complete with backslashes ?
> Some people say that this is desirable.
> What do you think?
> . I wanted to find a simple solution that students would use when they
> submitted their theses and dissertations. I know this process can't take
> much time or effort. I think of one of my students, who was an excellent
> student, that said, "Could you read all the documentation for datatool and
> tell me the highlights"? Uh, no.
> Maybe that will be possible soon.  3-5 years hence?
> Here is an example of how JAWS reads without alt text and a matrix
> equation (video)
> https://youtu.be/uN0RhcQw8RI
> Here is an example of how JAWS reads with alt text and a matrix equation
> (video)
> https://youtu.be/M4w_8yP88II
> My tagged thesis posted on our institutional repository (PDF).
> https://works.bepress.com/tammy_stitz/6/
> I'll have a look at this.
> Thanks for the link.
> All the best,
>    Ross
> Best Regards,
> Tammy Stitz
> Associate Professor, Bibliography
> Applied Sciences Librarian
> Email: tstitz at uakron.edu
> Office: 330-972-6192
> Science & Technology Library
> The University of Akron
> Akron, Ohio 44325-3907
> http://www.uakron.edu/libraries
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://tug.org/pipermail/accessibility/attachments/20180317/58cf9a7f/attachment.html>

More information about the accessibility mailing list