Best Practices For Creating Accessible Latex Documents

Creating accessible LaTeX documents benefits a wide range of readers with disabilities. By following key best practices around document structure, alternate text, logical reading order, and validation, LaTeX authors can make their papers, articles, books, and other documents far more usable for readers who interact with them with the help of assistive technologies like screen readers.

Understanding Accessibility Requirements

Designing accessible LaTeX files requires an understanding of general document accessibility guidelines as well as awareness of common PDF rendering issues that can create barriers for users with vision, motor, or other print disabilities.

Web Content Accessibility Guidelines (WCAG) Overview

Published by the World Wide Web Consortium (W3C), the Web Content Accessibility Guidelines (WCAG) outline four key principles to follow when creating any web-based or electronic content:

Table of Contents

Perceivable - Information must be available to users in ways they can perceive with their senses, using assistive technologies as necessary. This includes adding alternate text for images, creating structured headings, and ensuring color contrast.
Operable - Components must work with both keyboards and assistive devices. This includes logical focus order and hierarchical document structure marked up with LaTeX commands.
Understandable - Content needs to be clear and limit ambiguity. Writers should structure documents well, highlight key terminology, and explain complex expressions like formulas.
Robust - Documents must maximize compatibility with both current and future technologies like screen readers. Following semantic structure in LaTeX markup bolsters robust accessibility.

While developed for web pages, these principles provide an excellent high-level framework when optimizing LaTeX documents for accessibility as well.

Common Accessibility Issues in Documents

In addition to overall web accessibility guidelines, specific PDF rendering issues can create barriers for disabled readers attempting to use screen readers or other assistive technologies with LaTeX papers and books. Common problems include:

Lack of semantic document structure elements like headings
Missing alternate text descriptions for images and charts
Illogical tab order focus due to print-centric LaTeX code order
Undescribed links, tables, formulas, and other components
Inaccessible embedded multimedia like videos without captions

Paying attention to these key areas when authoring LaTeX documents can dramatically improve accessibility for the widest possible audience worldwide.

Adding Document Metadata

Enriching LaTeX files with descriptive metadata provides essential high-level context for readers interacting using assistive technologies like screen readers before diving deeper into the content itself.

Use \title, \author, \date Metadata

Set the foundation by adding LaTeX \title, \author, and \date commands with details on the paper, author identities, and publication date:

\title{Creating Accessible \LaTeX{} Documents}  

\author{Daniele Procida}  

\date{\today}

Screen reader users accessing PDF files exported from LaTeX can then understand key details on when a document was written along with context on its purpose just from these metadata headings alone before proceeding further.

Set Document Language with Babel Package

The babel LaTeX package plays a key role in accessibility by enabling authors to definitively set the human language used throughout a document. This assists screen readers with pronunciation and grammar rules when interpreting content later on.

For example, to clearly indicate a LaTeX file uses American English, authors would include:

\usepackage[english]{babel}

Setting the definitive human language in babel provides crucial context right from the start when a blind user accesses a LaTeX-generated PDF export using a screen reader.

Structuring Content Clearly

Creating an accessible logical structure that clearly delineates headings, sections, paragraphs, and other elements with semantic LaTeX markup gives both sighted readers and assistive technologies a hierarchy to latch onto when digesting content.

Use Logical Heading Hierarchy with \section, \subsection

By using heading commands like \section and \subsection to indicate document hierarchy, LaTeX authors provide a vital outline rendering correctly in accessibility tools like screen readers even if visual styling issues occur in print PDFs.

\section{Introduction}

\subsection{Defining Accessibility}

If headings ever fail to render appropriately in final PDF exports, the assistive technology user can still digest the content effectively thanks to the underlying semantic structure provided by logical LaTeX markup instead.

Ensure Logical Reading Order with Source Code Order

The sequence of LaTeX markup in the original source .tex document defines the logical reading order assisting screen reader users. Avoid reordering content blocks solely for visual formatting reasons to prevent confusing jumps when read linearly later on instead.

\section{Section 1 Heading}

Paragraph text in logical sequence based on LaTeX source order...

\section{Section 2 Heading}

Paragraph text maintains sequence flowing logically from first section...

By keeping paragraphs, equations, figures, and other components ordered logically following headlines marked up with \section and similar hierarchy tags in LaTeX, the source document structure benefits both visual layout for sighted readers and an essential outline for assistive technologies to follow in sequence.

Describing Images, Figures and Tables

Tables, graphs, diagrams, photos, and other non-text visual elements pose barriers for blind users and others relying on screen readers without adequate alternate text descriptions provided in the LaTeX markup.

Add Descriptive Alternate Text with \alt Command

Using the \alt command, LaTeX authors can insert concise but highly descriptive alternate text summaries conveying a visual asset’s meaning and relevance for non-sighted audiences.

  
\begin{figure}
  \includegraphics[width=\linewidth]{diagram.jpg}
  \caption{Accessibility layers in LaTeX ecosystem}
  \alt{Diagram showing document content, LaTeX markup language, PDF renderer, and accessibility tools interfacing with PDFs}  
\end{figure}

With descriptive alternate text on all figures provided in the raw .tex document, screen reader users examining resulting PDFs can contextualize images relying on the alt descriptions rather than the purely visual content itself.

Associate Captions Clearly Using \caption

The LaTeX \caption command ties together figures, images, tables, and other visuals with necessary details on what each conveys:

\begin{table}
\caption{Top Accessibility LaTeX Packages}
\begin{tabular}{l r}
  Package & Usage \\
  accsupp & Math accessibility \\ 
  accessiblerules & Table markup \\
\end{tabular}
\end{table}

Without a \caption instantiating descriptions for assistive technology users, they lack context required to understand the relevance of presented visual components embedded in documents.

Creating Accessible Links

Hyperlinks form connections tying related content together in web documents. Authors must enhance link semantics for accessibility using LaTeX markup.

Indicate Links Using \ref and \href

Visually discreet links in paragraphs easily missed when scanned by screen readers require descriptive identifiers in LaTeX instead:

An overview of image descriptions is available in \href{sec:img-desc}{Section 4.2}. Tables receive similar treatments covered in \ref{sec:tables}.

Here \href sets a rich internal document link with customized link text while \ref generates a semantic reference integrating with landscapes' existing heading structure.

Add Link Context with \desc Command

Avoiding naked links like bare URLs without surrounding descriptors, using \desc authors introduce beneficial context:

 
\href{https://latex-project.org}{\desc{The LaTeX Project website}}

This appends the phrase "The \LaTeX{} Project website" after the link when read by screen readers, identifying its destination sans any visual cues.

Formatting Math Equations

Math expressions, formulas, and scientific equations pose comparable accessibility issues to charts or diagrams without machine-readable parallel representations.

Use LaTeX Accessibility Packages Like accsupp

Employ accsupp and related packages ensuring math equations format reliably when exported from LaTeX to PDF:

\usepackage{accsupp}

\begin{document}  

\begin{equation} 
x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} 
\end{equation}

\end{document}

Accsupp generates stable document object model (DOM) trees preserving semantic LaTeX equation structures legible to screen reader technologies downstream.

Add MathML Equivalents with \mathml Command

Further augment equations by adding parallel MathML markup as an extra layer of semantic enrichment:

\mathml{
   $x = \frac{- b \pm \sqrt{b^{2} - 4 a c}}{2 a}$ 
}

While visual presentation remains unchanged, adding MathML strengthens the LaTeX document model for deeper semantic analysis by non-visual users leveraging math accessibility support in their assistive technology.

Validating Accessibility

After optimizing LaTeX document source code for accessibility, authors must validate resulting PDF exports confirm barriers do not persist preventing use by disabled audiences.

Use Accessibility Checkers Like Accessibility Audit

Run final PDFs through diagnostic validators like Microsoft Word's Accessibility Checker seeking issues around:

Missing alternate text on images
Tables lacking associated descriptions
Unlabeled interactive form elements
Other failures indicating problems

Address all flagged validation problems through iterative improvements to source LaTeX contents until eliminating warnings.

Manually Review with Screen Readers

As a final quality check, directly open the finished PDF in assistive tools like the NVDA screen reader on Windows or VoiceOver on macOS to verify an optimal end-user experience prevails:

Do headings, links, captions flow logically?
Is visual media contextually reinforced for non-sighted users?
Do math expressions and tables make sense when read aloud?

Refining LaTeX documents directly through the assistive technology interface provides crucial final confirmation format barriers no longer persist at publication.