W3C WAI

Notes on Accessible Presentations

This page is outdated. See updated information in How to Make Presentations Accessible to All.

Introduction

This document provides information on making a presentation accessible to:

People with disabilities, who may not be able to see displayed material at all, people using assistive listening devices through the sound system, people with low vision who cannot read small text, etc.
People sitting in the back of the room who cannot read displayed small text
Video recordings of the presentation that may not be able to make displayed small text readable
Audio-only recordings of the presentation, which do not capture any visual display
People participating in the meeting remotely via phone who are not able to see your display

Examples of accessible HTML slides and images are provided below.

Display large text and use large images: Ensure that the text and images in your "slides" and other displayed information is large enough to be easily read from the back of the room. For HTML slides, don't specify an absolute font size (see WCAG 1.0 Guideline 3.4); allow the reader to choose their own font size preference when they read your slides.
Include descriptions of visuals in online presentations: For HTML presentation material, include a text alternative for images and other visuals, per WCAG 1.0 Checkpoint 1.1. For example, provide an "alt" attribute for each IMG elements that conveys the meaning of the image, as well as for each OBJECT element.; For complex images, provide a link to a detailed description of the content of the image through a "longdesc" attribute in IMG element, a link inside an OBJECT element, or a description link marked with [D]. (For help, see the list of techniques.); National Braille Association provides good instructions for describing complex images.
Ensure that your online presentation materials are accessible: HTML pages should conform to (at a minimum) Level A the Web Content Accessibility Guidelines 1.0 (checklist), and preferably to Level AA. Accessibility evaluation tools and guidance at "Evaluating Web Sites for Accessibility" can help with checking accessibility.

Describe images and other visuals: Verbally describe any images or other visuals that you display. To help with this, pretend that there are people participating in the meeting via phone - what do you need to tell them about what is being displayed.
Be careful about saying things like, "As you see in the graph, there was a significant jump in usage." Any references to the visual will likely need a brief explanation of what is being displayed.
Use the microphone for ALDs: Most assistive listening devices (ALDs) connect to the room's sound system. Therefore, if someone is using such an ALD, you must use the sound system (microphone), even if other people can hear you without it.
When people are following along remotely: If you have an online presentation that people are following along remotely or if people might be listening to the audio in the future and following along with the online presentation, remember to say where you are in the online present ion, e.g., "Slide 7..."

An example of accessible slides are Wendy Chisholm and Shadi Abou-Zahra's "Metadata for Accessibility Adaptation." It contains complex images with descriptions, valid HTML, and is generated with the W3C slidemaker tool.

a short description of the image in an "alt" attribute: "System setup for experimental text captioning at SC2002"
a detailed content of the image available through the "longdesc" attribute (and a [D] link because some tools don't yet understand the "longdesc" - [D] links are not required)
an SVG version, which provides more structure that may be used by some clients to explain different parts of the image to people who cannot see the image (SVG version is helpful, yet not required)