Somewhere over the rainbow. Color blindness and user interface design: a critical review in the era of digital ecosystems

8,5% of the population (8% of man and 0,4% of women). It is considered a physical impairment in some context of communication and interactions where a huge part of the messages is carried by color language and chromatic signs. In a world where most of the interactions online or experienced in mobile devices are still based on graphical interfaces, this condition could be a limit in everyday life. According to WAI - Web Accessibility Initiative launched by W3Consortium and the Italian law n. 4/2004 (Legge Stanca), visual and interface design have now defined guideline to allow a better user experience also for color-blind people. The paper proposes a critical review of the design paradigms, discussing the role of colors and contrast both as a visual language component and accessibility issue underlining the recent evolution raised by the introduction of mobile devices and the ecosystem approach to digital environments