Conventional techniques of assessing contrast in displays fall short and often vary depending on reflections that caused "veiling glare" in the measurement device's optical system. Researchers at the National Institute of Standards and Technology have developed a more accurate measurement technique using an open-ended cone that significantly reduces the amount of reflected light reaching the detector of a contrast-measurement device. Measuring with the cone in place more accurately produces the ratio of a white area's luminance to a black area's luminance, a factor that strongly influences the perceived quality of a display, according to the researchers.