This study aims to clarify whether the difference in light source (white LED and fluorescent lamp), affects the readability of various colored text on various colored backgrounds. We also investigated whether the readability of color letters was different for readers under of different ages. Test stimuli with 20 color combinations were compared in terms of their readability by elderly readers under each type of lighting. Test results showed that the lightness difference of colored text varied under different lighting and affected its readability. Meanwhile, result of an experiment using nine color combinations by blue or red with the young and elderly subjects confirmed that age affects readability. This might be due to the reduced sensitivity to lightness of elderly subjects not only in the short-wavelength region but also in the long-wavelength region.
