Constructing a POUR Website
Perceivable

All communication relies on the senses. The most relevant senses to web content are sight, hearing, and touch. If users cannot perceive content, it is inaccessible by definition. Obvious as that may seem, many sites contain web content that cannot be perceived by some of its target users.

Sight

Users with full vision can read text, view images, understand visual cues in page layouts, interpret symbolic meaning of colors, and so on. This mode of perception is powerful, and designers should take full advantage of its communicative strengths. For people who are deaf, visual cues take on heightened importance.

However, users who are blind or vision-impaired cannot take full advantage of this mode of communication. For these users, information must be presented in a format which they can more easily perceive, such as audio. Screen readers can perform some of this conversion, if the content is designed with accessibility in mind.

Hearing

Although the web is thought of as primarily a visual medium, it also carries Zoom meetings, Netflix streams, podcasts, and other audio-heavy content. Technologies and methods exist for making audio information available to users with auditory disabilities. These technologies and methods can only help users, though, if designers and developers use them to make the information accessible to users who cannot hear it.

Touch

Individuals who are deaf and blind rely on touch for perceiving web content. The fingers can be used to perceive textual information printed in Braille formats, including refreshable Braille peripheral devices that convert text on a web page into Braille output.

Transformability

Since not everyone has the same abilities or equal use of the same senses, one of the main keys to accessibility is ensuring that information is transformable from one form into another, so that it can be perceived in multiple ways. Text can be transformed into audio and into Braille by the assistive technologies used by people with disabilities. Audio can be transformed into text, ideally before it reaches the user, because real-time speech-to-text conversions can be prone to errors. Graphics, animations, and videos are like audio in the sense that developers must provide the text alternative to users.

Overall, text is the most easily and most universally transformable format. However, this does not mean that text-only versions are the answer to web accessibility. On the contrary, non-text elements in many cases are crucial.

Content vs. Style and Presentation

Content should be separable from style. Although visual style can enhance the user experience, and in some cases even improve comprehension, the main message should not depend on the mode of presentation. This is important because not all users will be able to perceive the presentational look and feel aspects of web content. The message should remain clear through semantic structure, which is preserved when styles are turned off or not available to the user.

Background colors, graphics, and sounds should not interfere with the content. If the main content is presented in an audio format, background sounds should not obscure the message. Content presented in a visual format should likewise be distinguishable from decorative visual elements. Text should be distinguishable from its background by ensuring sufficient contrast.