6 ms·

LaTeX is the first PDF/UA-2 compliance accessible PDF producer

219 points by anewhnaccount2 2y ago

leni536 2y ago
Is this pdf standard freely accessible? How widely supported even PDF 2.0 is?
- nullindividual 2y ago
  It is free - https://pdfa.org/announcing-no-cost-access-to-iso-32000-2-pdf-2-0/ https://pdfa.org/announcing-no-cost-access-to-iso-32000-2-pd...
  - mananaysiempre 2y ago
    Thank you so much! Very nice to see that ISO was convinced to once again follow the promise (to Adobe) of no-cost access to the PDF standard that they kept until PDF 1.7 but broke with PDF 2.0. However, TFA is not about PDF, it is about a profile called PDF/UA-2 aka ISO 14289-2. That one is $223 from the PDF Association[1] or 173 CHF from the ISO[2]. [1] https://pdfa.org/iso-14289-2-pdfua-2/ https://pdfa.org/iso-14289-2-pdfua-2/ [2] https://www.iso.org/standard/82278.html https://www.iso.org/standard/82278.html
- anewhnaccount3 2y ago
  It's very early days for clients. I guess the support is not really there yet. However most publishers and eprint archives have settles on pdfs rather than html annoyingly, so this is one of our best hopes of accessibility for academic publications.
skadge 2y ago
Is texlive 2024 producing tagged PDF out of the box? That would be awesome! If not, is there somewhere some instructions/tutorials explaining the steps to follow?
- elashri 2y ago
  > Is texlive 2024 producing tagged PDF out of the box? Not yet. There is Tagged PDF project [1] which aims to do something like that. there is tagpdf [2] package that try to do some of these things. If you need good instructions I would suggest overleaf tagging tutorial [3]. [1] https://www.latex-project.org/publications/indexbytopic/pdf/ https://www.latex-project.org/publications/indexbytopic/pdf/ [2] https://ctan.org/pkg/tagpdf https://ctan.org/pkg/tagpdf [3] https://www.overleaf.com/learn/latex/An_introduction_to_tagged_PDF_files%3A_internals_and_the_challenges_of_accessibility https://www.overleaf.com/learn/latex/An_introduction_to_tagg...
- anewhnaccount3 2y ago
  No, but it's getting easier and easier. To opt into this testing stage functionality you need to add a few tags, and may eventually have to work around some package incompatibilities. Take a look at https://www.latex-project.org/news/2023/03/13/latex-dev-1/ https://www.latex-project.org/news/2023/03/13/latex-dev-1/ for more info.
oriettaxx 2y ago
can somebody explain? I already can create PDF from latex, what does this repo add to it?
- anewhnaccount3 2y ago
  In the future better accessibility for screen readers of text (paragraph breaks), images (alt text), tables (control of reading order), and math formulae. It's up to the pdf readers too though.
- lxgr 2y ago
  PDF/UA makes PDFs accessible, which can otherwise be very hard to parse for screenreaders or display software that wants to reflow them (e.g. for reading them on small displays). Without special hints (that are ignored by regular PDF readers or printers), PDF is essentially a vector graphics format, and any of these tasks amount to an exercise in OCR. This is a somewhat little-known fact about PDFs, since many viewers do in fact implement many of these OCR-like heuristics to provide features such as text selection, search etc. that make it look a lot like a text-based format, but it really is a vector graphics format at heart. PDF/UA makes this a bit easier. As an example, consider a multiple column layout, as is often used in scientific articles. PDF-creating software not concerned with accessibility might just intersperse all columns line by line (i.e. present text in presentational left-to-right, top-to-bottom fashion), but it could just as well achieve the same outcome by drawing column by column in semantic order. Beyond encouraging that, I believe PDF/UA also defines a bunch of (invisible) metadata tags that readers can use to figure out semantic structuring of a document.
  - dguest 2y ago
    Sounds like this would massively simplify converting scientific articles back to HTML or text. Seriously, I know of one experiment that has O(thousands) of papers as latex source, which they publish as PDFs and which (more recently) they convert back to markdown with some ML-based image to text engine. All so that it can be fed to a vector database to make searching easier, of course. PDFs are a terrible format for machine readable information (and thus for reproducible science), but they are the currency of the scientific community and as such will be the standard output for the foreseeable future.
ThePowerOfFuet 2y ago
> At the present time we are not distributing the modified TeX sources that generate these tagged examples Why not?
- tetris11 2y ago
  I am also baffled. I searched several repos for any concrete examples of what this all actually means. Blip. Maybe there are no source changes, and everything is handled by the engine, or maybe it introduces some extra \startread \endread tags without the need of an environment.
deleted 2y ago
[deleted]
codetrotter 2y ago
> Using Tagged PDF for Accessibility and Reuse in PDF 2.0 https://pdfa.org/wtpdf/ https://pdfa.org/wtpdf/ This sounds amazing! Some years ago I was involved with a project for a company where we tried to extract some data from some PDF files they had. But neither OCR nor my attempts at reconstructing order of text in the documents panned out in the end, and it all ended in tears :( Perhaps one day in the future dealing with extracting data from PDFs will be less of a mess.
- layer8 2y ago
  Tagged PDF is nothing new, it was added with PDF 1.4 in 2001, in order to provide an HTML-like structure in PDFs (potentially allowing PDF-HTML round-tripping). But a lot of software doesn’t bother producing it.
jimhefferon 2y ago
If you are interested in this work, you could look into joining or just supporting the TeX Users Group, https://www.tug.org https://www.tug.org, or your local users group. A lot of folks doing good things, including the ones who are doing this.
- jimmySixDOF 2y ago
  and for anyone in the TeX User Group there is this fun experiment in Typesetting which starts off with the amazing TeX origin story https://youtu.be/Y65FRxE7uMc https://youtu.be/Y65FRxE7uMc
  - rsa4046 2y ago
    Great link, thank you.
  - JadeNB 2y ago
    Also on HN recently: https://news.ycombinator.com/item?id=40608332 https://news.ycombinator.com/item?id=40608332
g15jv2dp 2y ago
This must be a joke. LaTeX cannot even produce accessible PDF today. Believe me, I tried. I write my lecture notes in LaTeX and some of my students have disabilities. I tried to follow these guides https://tex.stackexchange.com/questions/261537/a-guide-on-how-to-produce-accessible-pdf-files https://tex.stackexchange.com/questions/261537/a-guide-on-ho... (note the Feb 2024 update). No matter how technically "correct" the LaTeX people want it to be, even a PDF produced by MS Word was more accessible for my students.
- JohnKemeny 2y ago
  Since you are familiar with the TeX StackExchange, perhaps you can ask there? As you might be aware, the author of the message is David Carlisle, a very active member at TeX (766k rep) and is also a maintainer of many popular packages. Needless to say, the guide you followed is 8 years old; Perhaps some things have changed.
  - g15jv2dp 2y ago
    > Since you are familiar with the TeX StackExchange, perhaps you can ask there? I have. I don't want to link my HN identity to my SE identity (which is tied to my real world identity through mathoverflow) so I won't link here. > Needless to say, the guide you followed is 8 years old; Perhaps some things have changed. As I said, it was updated in February 2024. I was written by Ulrike Fischer who's also very involved in latex3. It's basically the current state of the art in accessible PDFs. And it's still not good enough. I wish it were otherwise, but latex is the pinnacle of design-by-committee and tech debt. Given how latex3 turned out, I'm very pessimistic. The only thing latex has going for it is inertia.
- xworld21 2y ago
  The tagging work is still highly experimental. A major missing element is equation tagging: for now, you need to produce an 'associated MathML' file externally, for instance using LaTeXML. Even then, PDF readers do not support the MathML tags yet! If anything, I am sure that the LaTeX3 team would appreciate you posting minimal examples of mistagged PDFs. If you want to produce accessible documents from LaTeX, you should convert to HTML. ATs such as screen readers just work miles better than with PDFs, and given the resources put in developing browsers compared to PDF readers, I don't think this will change any time soon. Luckily conversion from LaTeX to HTML is very feasible today, as proved by arXiv. (Shameless plug: I maintain BookML specifically to help lecturers with the LaTeX to HTML work)
jimhefferon 2y ago
This work is ongoing. There will be a number of papers and a one-day workshop at the upcoming TeX Users Group meeting https://tug.org/tug2024/ https://tug.org/tug2024/. People interested in the technical details may find the page of the working group useful https://tug.org/twg/accessibility/ https://tug.org/twg/accessibility/.

Is this pdf standard freely accessible? How widely supported even PDF 2.0 is?

nullindividual 2y ago
It is free - https://pdfa.org/announcing-no-cost-access-to-iso-32000-2-pdf-2-0/ https://pdfa.org/announcing-no-cost-access-to-iso-32000-2-pd...
- mananaysiempre 2y ago
  Thank you so much! Very nice to see that ISO was convinced to once again follow the promise (to Adobe) of no-cost access to the PDF standard that they kept until PDF 1.7 but broke with PDF 2.0. However, TFA is not about PDF, it is about a profile called PDF/UA-2 aka ISO 14289-2. That one is $223 from the PDF Association[1] or 173 CHF from the ISO[2]. [1] https://pdfa.org/iso-14289-2-pdfua-2/ https://pdfa.org/iso-14289-2-pdfua-2/ [2] https://www.iso.org/standard/82278.html https://www.iso.org/standard/82278.html
anewhnaccount3 2y ago
It's very early days for clients. I guess the support is not really there yet. However most publishers and eprint archives have settles on pdfs rather than html annoyingly, so this is one of our best hopes of accessibility for academic publications.

Is texlive 2024 producing tagged PDF out of the box? That would be awesome! If not, is there somewhere some instructions/tutorials explaining the steps to follow?

elashri 2y ago
> Is texlive 2024 producing tagged PDF out of the box? Not yet. There is Tagged PDF project [1] which aims to do something like that. there is tagpdf [2] package that try to do some of these things. If you need good instructions I would suggest overleaf tagging tutorial [3]. [1] https://www.latex-project.org/publications/indexbytopic/pdf/ https://www.latex-project.org/publications/indexbytopic/pdf/ [2] https://ctan.org/pkg/tagpdf https://ctan.org/pkg/tagpdf [3] https://www.overleaf.com/learn/latex/An_introduction_to_tagged_PDF_files%3A_internals_and_the_challenges_of_accessibility https://www.overleaf.com/learn/latex/An_introduction_to_tagg...
anewhnaccount3 2y ago
No, but it's getting easier and easier. To opt into this testing stage functionality you need to add a few tags, and may eventually have to work around some package incompatibilities. Take a look at https://www.latex-project.org/news/2023/03/13/latex-dev-1/ https://www.latex-project.org/news/2023/03/13/latex-dev-1/ for more info.

oriettaxx 2y ago

can somebody explain? I already can create PDF from latex, what does this repo add to it?

anewhnaccount3 2y ago
In the future better accessibility for screen readers of text (paragraph breaks), images (alt text), tables (control of reading order), and math formulae. It's up to the pdf readers too though.
lxgr 2y ago
PDF/UA makes PDFs accessible, which can otherwise be very hard to parse for screenreaders or display software that wants to reflow them (e.g. for reading them on small displays). Without special hints (that are ignored by regular PDF readers or printers), PDF is essentially a vector graphics format, and any of these tasks amount to an exercise in OCR. This is a somewhat little-known fact about PDFs, since many viewers do in fact implement many of these OCR-like heuristics to provide features such as text selection, search etc. that make it look a lot like a text-based format, but it really is a vector graphics format at heart. PDF/UA makes this a bit easier. As an example, consider a multiple column layout, as is often used in scientific articles. PDF-creating software not concerned with accessibility might just intersperse all columns line by line (i.e. present text in presentational left-to-right, top-to-bottom fashion), but it could just as well achieve the same outcome by drawing column by column in semantic order. Beyond encouraging that, I believe PDF/UA also defines a bunch of (invisible) metadata tags that readers can use to figure out semantic structuring of a document.
- dguest 2y ago
  Sounds like this would massively simplify converting scientific articles back to HTML or text. Seriously, I know of one experiment that has O(thousands) of papers as latex source, which they publish as PDFs and which (more recently) they convert back to markdown with some ML-based image to text engine. All so that it can be fed to a vector database to make searching easier, of course. PDFs are a terrible format for machine readable information (and thus for reproducible science), but they are the currency of the scientific community and as such will be the standard output for the foreseeable future.

ThePowerOfFuet 2y ago

> At the present time we are not distributing the modified TeX sources that generate these tagged examples Why not?

tetris11 2y ago
I am also baffled. I searched several repos for any concrete examples of what this all actually means. Blip. Maybe there are no source changes, and everything is handled by the engine, or maybe it introduces some extra \startread \endread tags without the need of an environment.

deleted 2y ago

[deleted]

codetrotter 2y ago

> Using Tagged PDF for Accessibility and Reuse in PDF 2.0 https://pdfa.org/wtpdf/ https://pdfa.org/wtpdf/ This sounds amazing! Some years ago I was involved with a project for a company where we tried to extract some data from some PDF files they had. But neither OCR nor my attempts at reconstructing order of text in the documents panned out in the end, and it all ended in tears :( Perhaps one day in the future dealing with extracting data from PDFs will be less of a mess.

layer8 2y ago
Tagged PDF is nothing new, it was added with PDF 1.4 in 2001, in order to provide an HTML-like structure in PDFs (potentially allowing PDF-HTML round-tripping). But a lot of software doesn’t bother producing it.

jimhefferon 2y ago

If you are interested in this work, you could look into joining or just supporting the TeX Users Group, https://www.tug.org https://www.tug.org, or your local users group. A lot of folks doing good things, including the ones who are doing this.

jimmySixDOF 2y ago
and for anyone in the TeX User Group there is this fun experiment in Typesetting which starts off with the amazing TeX origin story https://youtu.be/Y65FRxE7uMc https://youtu.be/Y65FRxE7uMc
- rsa4046 2y ago
  Great link, thank you.
- JadeNB 2y ago
  Also on HN recently: https://news.ycombinator.com/item?id=40608332 https://news.ycombinator.com/item?id=40608332

g15jv2dp 2y ago

This must be a joke. LaTeX cannot even produce accessible PDF today. Believe me, I tried. I write my lecture notes in LaTeX and some of my students have disabilities. I tried to follow these guides https://tex.stackexchange.com/questions/261537/a-guide-on-how-to-produce-accessible-pdf-files https://tex.stackexchange.com/questions/261537/a-guide-on-ho... (note the Feb 2024 update). No matter how technically "correct" the LaTeX people want it to be, even a PDF produced by MS Word was more accessible for my students.

JohnKemeny 2y ago
Since you are familiar with the TeX StackExchange, perhaps you can ask there? As you might be aware, the author of the message is David Carlisle, a very active member at TeX (766k rep) and is also a maintainer of many popular packages. Needless to say, the guide you followed is 8 years old; Perhaps some things have changed.
- g15jv2dp 2y ago
  > Since you are familiar with the TeX StackExchange, perhaps you can ask there? I have. I don't want to link my HN identity to my SE identity (which is tied to my real world identity through mathoverflow) so I won't link here. > Needless to say, the guide you followed is 8 years old; Perhaps some things have changed. As I said, it was updated in February 2024. I was written by Ulrike Fischer who's also very involved in latex3. It's basically the current state of the art in accessible PDFs. And it's still not good enough. I wish it were otherwise, but latex is the pinnacle of design-by-committee and tech debt. Given how latex3 turned out, I'm very pessimistic. The only thing latex has going for it is inertia.
xworld21 2y ago
The tagging work is still highly experimental. A major missing element is equation tagging: for now, you need to produce an 'associated MathML' file externally, for instance using LaTeXML. Even then, PDF readers do not support the MathML tags yet! If anything, I am sure that the LaTeX3 team would appreciate you posting minimal examples of mistagged PDFs. If you want to produce accessible documents from LaTeX, you should convert to HTML. ATs such as screen readers just work miles better than with PDFs, and given the resources put in developing browsers compared to PDF readers, I don't think this will change any time soon. Luckily conversion from LaTeX to HTML is very feasible today, as proved by arXiv. (Shameless plug: I maintain BookML specifically to help lecturers with the LaTeX to HTML work)

jimhefferon 2y ago

This work is ongoing. There will be a number of papers and a one-day workshop at the upcoming TeX Users Group meeting https://tug.org/tug2024/ https://tug.org/tug2024/. People interested in the technical details may find the page of the working group useful https://tug.org/twg/accessibility/ https://tug.org/twg/accessibility/.