Effect of text‐background lightness combination on visual comfort for reading on a tablet display under different surrounds

Abstract

AbstractMany tablets are designed to change display brightness or color with surround for enhancing visual comfort. Although both color and brightness of a surround may vary a lot, few studies investigated how text‐background lightness combination of a tablet display and surround jointly affect visual comfort, and how display white point affects visual comfort. In this study, 20 observers evaluated visual comfort of 20 text‐background lightness combinations of a 9.7‐inch tablet display through paired comparisons under five surrounds—a dark surround and four ambient lighting conditions comprising two levels of correlated color temperature (CCT)—3500 and 6500 K—and illuminance—300 and 3000 lx. The combination of a black text and a light‐gray background (i.e., L*background = 75.33; L*text = 1.6) was evaluated the most comfortable when there was ambient light regardless of CCT and illuminance. It was also evaluated the third most comfortable under the dark surround. The observers also evaluated the visual comfort of a dark text on five different white backgrounds under 3500 and 6500 K at 1000 lx. The color of the background that was judged as the most comfortable neither had the whitest appearance nor matched the color of the ambient light. The simultaneous adjustment of the display white point and the text‐background lightness combination merits further investigations.