The display device should be capable of producing a legible and interpretable image on the screen, even at the location of specular reflection on the screen from a bright, glaring light source in the environment. Additional Information: The contrast ratio of the visual display screen should be a minimum of 3:1 under specular illumination from a 1,000 candelas per square meter (cd/m2) (29 foot-lamberts (ft-L)) source subtending 15 degrees. See IDMS (2012) for measurement information.100