mako/uw_tex_letterhead
1
0
Fork 0
Code Activity

Enable tagging so the PDF/UA-2 claim is true

Browse Source 
The template declared pdfstandard=ua-2 and loaded tagpdf with
\tagpdfsetup{activate-all}, which sets /Marked true and writes the
conformance claim but does not turn on the kernel code that tags
document structure. The result passed veraPDF's ua2 profile while its
structure tree held nothing but /Document: every paragraph of the
letter was marked as an artifact, so the checker had no untagged real
content to complain about, and both alt= descriptions were dropped on
the floor.

That is a worse failure than an outright invalid file. A letter that
announces itself as accessible and contains nothing readable is the
one a person relying on a screen reader will trust.

Adding tagging=on fixes it: the built letter now carries twenty tagged
paragraphs and a Figure element holding the signature's alt text, and
still passes ua2. The manual tagpdf lines are dropped since the kernel
loads it.

This requires TeX Live 2025 or later; on TeX Live 2024 the key is
unknown and the build stops. The README gains that requirement, an
Accessibility section, and a warning that a veraPDF pass is necessary
but not sufficient.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Benjamin Mako Hill
2026-08-13 18:30:55 -07:00
parent 014b80ee72
commit a024557f7d
2 changed files with 48 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
README
View File

@@ -36,10 +36,47 @@ On Debian or Ubuntu, install the following packages:
On other systems, installing a full TeX Live distribution should
provide everything needed.
TeX Live 2025 or later is required. The tagging code is not in TeX
Live 2024, where the build stops with "the key
'document/metadata/tagging' is unknown". Debian trixie ships TeX Live
2024. On Overleaf, set the version under Menu > Settings > TeX Live
version; it is not always high enough by default on an older project.
The two required fonts Matrix-II and OpenSans are both included in
this repository, so no additional font packages are needed.
Accessibility
=============
The letter is a tagged PDF declaring PDF/UA-2 (ISO 14289-2). Two keys
in the \DocumentMetadata block at the top of the .tex file do this,
and both are needed: tagging=on loads the kernel code that puts the
text into the PDF's structure tree, and pdfstandard=ua-2 writes the
conformance claim. The claim without the tagging produces a letter
that passes a conformance checker while containing nothing a screen
reader can read, so keep them together.
Check a built letter with veraPDF (https://verapdf.org/, not packaged
in Debian):
verapdf -f ua2 washington_letterhead_letter-matrix-deptartment.pdf
Note that a PASS is necessary but not sufficient. A letter whose body
text is all marked as artifact passes too, because the standard only
requires that content which is not real be an artifact. Confirm there
is something in the structure tree as well:
python3 -c "import pikepdf,sys; d=pikepdf.open(sys.argv[1]); \
print(d.Root.get('/StructTreeRoot') and 'tagged' or 'UNTAGGED')" file.pdf
The signature image carries an alt= description, which is what a
screen reader announces in place of it. Keep that in place if you
swap in your own signature. The letterhead graphic in the page header
is treated as an artifact, like other running header content, so it
is skipped rather than described.
Encrypted signature files
===========================

13
washington_letterhead_letter-matrix-deptartment.tex
View File

@@ -1,4 +1,15 @@
% Tagged PDF (PDF/UA-2) accessibility setup.
%
% tagging=on is what actually builds the structure tree: it loads the
% kernel code that tags paragraphs, headings, and figures. Declaring
% pdfstandard=ua-2 on its own only writes the claim into the metadata.
% Without tagging=on this letter validated as PDF/UA-2 while its
% structure tree held nothing but /Document, its body text was marked
% as artifact, and the alt= descriptions below were silently dropped:
% a file that passes the checker and is unreadable to a screen reader.
% Needs TeX Live 2025 or later.
\DocumentMetadata{
tagging=on,
pdfversion=2.0,
pdfstandard=ua-2,
lang=en-US,
@@ -17,8 +28,6 @@
\usepackage[top=1.25in,left=1.25in,bottom=1.20in,right=1.25in]{geometry}
\usepackage{fontspec}
\usepackage{tagpdf}
\tagpdfsetup{activate-all}
\newopentypefeature{Contextuals}{NoAlternate}{-calt}
\defaultfontfeatures{Kerning=Uppercase,Ligatures=TeX}