Sensory characteristics

Criterion 1.3.3 is one sentence long: instructions for using content must not rely solely on sensory characteristics such as shape, colour, size, visual location, orientation, or sound. In practice it is a rule about copy, not about controls. “Press the round button on the right”, “see the sidebar to the left”, “click the icon above”, and “when you hear the tone, continue” are all the same defect: the sentence names its target by something the reader may not be able to perceive, when a name was available and free.

The reader it blocks most obviously is one listening rather than looking. A screen reader walks the interface as a sequence of named things, so shape and side simply are not in the account: two buttons that a sighted reader distinguishes instantly as the round one and the square one arrive as two buttons, in order, and the instruction has nothing to match on. The same failure hits magnification, where “on the right” is off screen, and readers with colour vision deficiency, which is why the hue half of this problem gets its own criterion in use of color.

The less discussed failure mode is that position words are fragile for everybody. A layout that reflows moves things: the button on the right becomes the button at the bottom on a phone, the left sidebar becomes a drawer behind a hamburger, and “above” becomes “below” the moment a column stacks. Help copy written against one breakpoint is quietly wrong at every other one, and screenshots in documentation age the same way. Naming the control instead makes the sentence survive the layout, which is a maintenance benefit long before it is an accessibility one.

The fix is not to strip the sensory detail out, it is to add the name and keep the detail as a bonus. “Press Continue, the round button on the right” reads naturally, helps a sighted reader find the thing faster, and still resolves for a reader who has neither shape nor side. Where the name has to match what is announced, label in name is the criterion that keeps the two spellings together. And if the copy cannot name the control because the control has no accessible name, the instruction was never the real bug.