Spectrum mapping technology based creation of a color-contrast reading environment to reach comfort and clarity.

Reading with a bit of yellowish or greenish paper, as compared to white paper, is thought to be more comfortable and friendly, and can help decrease eye fatigue to some degree. In this work, we try to map the light of different colors on a given paper within a region of interest to alter the colors presented by the paper and consequently influence the reading experience. We conducted an ergonomic experiment to study the comfort and clarity under consistent illuminance levels. We adopted 6 color series(red, yellow, green, cyan, blue, and magenta), 5 chroma levels(0, 10, 20, 30, 40), and 4 types of paper with the same hue(yellow) but different lightness(the white, light yellow, yellow, and dark yellow), and conducted pairwise selection experiments within each light color series. Results show that white and low chroma (≈10) color characteristics contribute to comfort, while higher chroma blue(30∼40) color benefits clarity. Referring to white, low chroma greenish and yellowish color characteristics are preferred in terms of comfort and clarity. This work proposes the spectrum mapping technology to endow the paper with new color effects and verifies that although spectrum compositions might differ, people's preferences and comfort perception are consistent with the same object color.

Does the smartphone's eye protection mode work?

People spend about 5-8 hours per day on phones, causing circadian disruption and eye fatigue, thus raising a great need for comfort and health. Most phones have eye protection modes, claiming a potential eye protection effect. To examine the effectiveness, we investigated the color quality, namely gamut area and just noticeable color difference (JNCD), and circadian effect, namely equivalent melanopic lux (EML) and melanopic daylight efficacy ratio (MDER), characteristics of two smartphones: iPhone 13 and HUAWEI P30, in normal and eye protection mode. The results show that the circadian effect is inversely proportional to color quality when the iPhone 13 and HUAWEI P30 changed from normal to eye protection mode. The gamut area changed from 102.51% to 82.5% sRGB and 100.36% to 84.55% sRGB, respectively. The EML and MDER decreased by 13 and 15, and, 0.50 and 0.38, respectively, affected by the eye protection mode and screen luminance. The EML and JNCD results in different modes show that the eye protection mode benefits the nighttime circadian effect at the cost of the image quality. This study provides a way to precisely assess the image quality and circadian effect of displays and elucidates the tradeoff relationship between them.