What is the difference between "Contrast Ratio" and "Brightness"? Contrast Ratio is the intensity between the darkest and the brightest aspects of the image. A higher contrast ratio, will deliver deeper and more detailed black and white image and / or picture. As for brightness, this is measured in intensity by cd/m2. The higher the brightness, the more beautiful will be the image and the possibilities of use will be better, for instance, in a dark and / or brightly-lit environment.