How to make video and audio accessible

Visual information in videos

Make sure videos use accessible colours and avoid flashing images. This helps people with colour blindness or photosensitive conditions use your content.

Using colour

Tiredness, screen brightness, light levels, age, and visual impairments can make colours harder to see.

Make sure colours used for important information have accessible contrast. Examples include:

on-screen caption text (open captions)
important text
informative images, such as charts

For a chart or graphs, ensure good contrast between:

text labels and background colours
lines and background colours
lines next to each other

Colour contrast

Colour contrast ratio measures brightness differences. Higher contrast makes text and images easier to see.

When creating video content:

important text and images must have a minimum contrast ratio of 3:1
the easiest to read colours have a minimum contrast ratio of 4.5:1.
decorative images or logos do not need accessible contrast.
do not use colour alone to show meaning (add text labels or patterns where needed)

Checking colour contrast

There are free tools you can use to check colour combinations in your content.

WebAIM's Contrast Checker is an online tool that works for most content. Use the dropper (see image) or enter hex or RGB colours to test contrast.

Screenshot of WebAIM Contrast Checker — Use the Colour Picker's dropper to find the colour's Hex Value.

Finding accessible colours

You can use the hex values for different colours, like #FFFFFF to:

find WCAG-compliant colour palettes with the Venngage Accessible Color Palette Generator.
see how colour combinations affect different people WhoCanUse website.

Flashing images

Avoid flashing images, such as strobe lights or lightning, because they can cause seizures, dizziness, nausea or disorientation.

If flashes are needed, reduce risk by:

having no more than three flashes per second
keeping flashes small and low contrast compared to other content

For example, if a scene has bright lightning, edit it so it flashes no more than three times in one second.

Making existing visual information accessible

If a video has already been published and some important visuals are not accessible:

provide a written description or summary near the video, or link to a separate page
allow users to request the content in another accessible format
update the video later to a fully accessible version when possible

This applies only to important visuals. Decorative images or background visuals do not need alternative descriptions.