Video, having both audio and visual elements, can be an engaging and accessible medium for learners who process information in different ways. Video can also be inaccessible to some students for a variety of reasons. The following practices that will be discussed, may not eliminate all barriers to access your video, but they will help to improve its accessibility for many more people.
Captioning
Captions are transcribed portions of video dialogue that appear on screen as the speaker is speaking the words. They can be added in real time by a human captioner or through speech recognition technology; they can also be added to recorded videos so viewers can read them during playback. Captioning videos improves access for students who are D/deaf, hard-of-hearing, or experience cognitive or learning disabilities.They may also be used by students who do not identify as having a disability but for whom English is not a first language, or viewing the video in a loud environment. The following image demonstrates how captions may appear on screen during a video.
Automated Captions
Having a transcript readily available is a compelling reason to work with a script! However, if you find that you’ve ad libbed more than you read from the script, machine automated captioning offers an alternative format for students who require or prefer a text alternative to audio. Automated captioning is built-in to several institutionally supported video creation tools, such as MacVideo and Echo360.
Automated captions can have a high accuracy rate – 95% to 99% – but even a small error can change the meaning of a sentence quite drastically. It is important to verify automated captions and correct them if there are errors. MacVideo’s interface allows you to easily make changes to their captions, as well as output them to an SRT file which can be used with other video platforms.
Note: you can create captions directly in Camtasia, but it is very labour intensive; upload the video file you export from Camtasia to MacVideo and use its automated captioning services instead.
Colour Contrast
The effective use of colour in your video can draw your learners’ attention, emphasize key points and add aesthetic interest to your video. However, your choice of colours should be considered with accessibility in mind. Using the wrong colour combinations can create a barrier for some students by making graphical elements more difficult to perceive.
Even if a pair of colours look nice together, it’s important to maintain a sufficient level of colour contrast within any content that is not decorative. Colour contrast compares the brightest colour to the darkest colour in the image and is typically expressed in a ratio, where a high ratio indicates a higher contrast. Smaller text should have a higher contrast ratio.
Try using a colour contrast checker to verify that the foreground text and background colour of your presentation slides have adequate contrast. Here are some examples:
1) This is an example of a colour contrast checker with the colour contrast rated as ‘Poor’.
2) This is an example of a colour contrast checker with the colour contrast rated as ‘Good’.
3) Here is another contrast checker example that rates the size of text in combination with the colour contrast, to meet different web accessibility standards. The example below has been rated a ‘Pass’ for WCAG AAA which is the highest accessibility rating.
Note: Review the Web Content Accessibility Guidelines (WCAG) 2.0 as a reference for creating accessible media with a successful WCAG 2.0 level AA rating, which is the required AODA (Accessibility for Ontarians with Disabilities Act) standard for websites.
Colour Blindness
Another consideration is colour blindness, which affects 5-10% of the population in its various forms. Red-green deficiencies are the most common, so avoid using red in any non-decorative content where possible and, in general, use means other than colour to convey information.
Describing Video
The visual imagery of video carries a lot of information but is not, unfortunately, accessible to all. While you don’t have to narrate everything that’s happening on the screen, you should at least:
- describe any images that are meant to convey content (i.e. those that are not decorative),
- reference aloud any important information that is on the slide or in the presentation.
If you catch yourself saying “as you can see from the slide…,” then it’s probably something that you’ll need to describe for students who are blind or have low vision.
Figures, videos, animations – consider how you will represent them in the video’s script if they are important to your students’ learning.
Video isn’t always the best modality
Although we certainly encourage you to use video in your teaching, there are also times when it’s not the best modality for the content or intended learning outcome associated with it. A web page with step-by-step instructions for a procedural task may be better than showing a video of it, when students want to quickly be able to jump to a particular step. You may know that some of your students have unreliable or low-bandwidth connections, and watching or downloading videos may be frustrating for them. There are a number of great reasons to create videos for students, but it’s also important to consider if video is the right tool for the learning task.