Color universal design without restricting colors and their combinations using lightness contrast dithering (Analysis of dither patterns distinguishability and lighting robustness)

The authors have been proposing a new method of color universal design without restricting usage of colors and their combinations named “lightness contrast dithering”. A key idea is that a solid color and a dithering of darker and lighter colors which approximate the solid color may look almost similar for people with normal color vision, while they could be distinguishable for people with color vision deficiencies since one is solid and the other is a pattern of dark and light colors. This paper reports the results of investigations on distinguishability of dither patterns (vertical, horizontal and oblique stripes) and lighting (illuminance and color temperature) robustness of lightness constrast dithering.