Avoid Relying on Sensory Characteristics

Saying a caption refers to an image "in the left column," or that they can register at an event by finding the person "at the green table," assumes the user sees the same layout, or has the same color perception.

If you rely solely on one sensory characteristic (spatial relationship, size, position, color, or sound) in your instructions, you are likely causing barriers to access for people who are non-sighted, low-sighted, colorblind or cognitively impaired.

Best Practices

Rather than having a caption on one side of the page referring to an image "at the far left," move the caption next to the image.
Provide multiple means of understanding if your content is drawing attention to one of those attributes. E.g., rather than saying "Sign in at the green table," say "Sign in at the green table facing the front entrance."
When particular senses are necessary to understand intrinsically visual content, provide a plain-text alternative: e.g., summarize a chart in its caption, or link to a table with the same information.

Don't do This

Tips for the exam tomorrow; especially note the bold items!

The test will cover chapters one through five.
Remember that green questions are for extra credit. Don't panic if they seem hard.

Why Is This Wrong?

Referring to a section of content by its purely visual formatting creates a barrier. In this example, the fact that some text is bold may not be read aloud by a screen reader, and may also not be easily apparent to a low vision reader. A color blind reader may also not be able to tell which box is green on the day of the exam.

Do This

Tips for the exam tomorrow; especially note the first item!

The test will cover chapters one through five (not "through six" as we said in class).
Remember that the green questions (the last page) are for extra credit. Don't panic if they seem hard.

Why Is This Better?

It is no longer necessary to see or hear that some text is bold; all users should be able to find the first item on the list or read the parenthetical comment.
Students who are colorblind no longer have to worry that they will not be able to tell which questions are optional; they have been given a secondary way to identify them ("the last page").