10/15/2026
Color can support meaning, but it should not carry the whole message.
If a chart uses red for overdue and green for complete, also add words, symbols, patterns, or labels so people can understand the status without distinguishing the colors.
The same idea applies to forms, buttons, links, schedules, and documents. A quick test is to view the design in grayscale. If the meaning disappears, add another cue.