2011 Volume 32 Issue 3 Pages 67-74
To evaluate Web Content Accessibility Guidelines (WCAG) 2.0 success criteria on luminance contrast ratio, we measured the spectral radiance for web-safe colors and calculated age-related relative luminance and contrast based on age-related spectral luminous efficacy as defined by the Japanese Industrial Standards. As a result, luminance ratio reduction by aging was observed in the bluish and greenish hue, saturation, value (HSV) hue region, especially among people in their 50s and older in the bluish region (HSV hue 240 degrees). Also, by calculating the age-related luminance contrast ratio against black, the incremental ratio of luminance contrast dispersed by aging, with 47 out of 140 colors showing 10% or more decremental ratio in their 70s. Considering the effect of aging, the WCAG 2.0 success criteria are mostly suitable for web-safe colors, as there were only a few colors that changed eligibility for WCAG 2.0, while we must be careful using colors in the blue region, due to the decrease in luminance contrast ratio. It is also recommended that we use colors with HSV value of 204 or more against a black background when presenting visual information to aged persons.
