Daltonization

Daltonization is a computational technique that modifies the colours in an image or on a screen to make them more distinguishable for people with colour vision deficiency (CVD). Named after John Dalton, who first described his own colour blindness in the 18th century, daltonization algorithms typically simulate how a person with CVD perceives colours, identify confusing colour pairs, and then shift hues to increase differentiation. While daltonization and related recolouring tools are the most widely available assistive technology for CVD — built into Windows, macOS, iOS, and Android — research suggests they are rarely used as intended, often creating new colour confusions, distorting learned colour knowledge, and producing aesthetically unpleasant results that users find "ugly." Many people with CVD prefer on-demand toggling rather than always-on filtering.