Glossary A–ZLetter A
Accessibility
Accessibility means that content and devices can be perceived and used by people with visual, hearing, motor or cognitive impairments as well.
For screens it mainly concerns legibility, contrast, display time and the operation of interactive devices.
In practice this means large, clear lettering, sufficient contrast between text and background, enough time to read and no information conveyed by colour alone. Videos without sound need subtitles or on-screen text. Interactive terminals should be mounted at a height that can be reached from a wheelchair and offer an alternative to touch-only operation, such as speech output. Rapidly flashing content should be avoided because it can trigger seizures in people with epilepsy; the Web Content Accessibility Guidelines (WCAG) set the limit at three flashes per second.
In Germany, the Accessibility Strengthening Act (BFSG) imposes obligations on certain products and services, including certain interactive self-service terminals. According to its wording, a screen that only displays information is not among them. Good legibility is still a matter of care, because it benefits every viewer.