<P> In marketing literature, contrast ratios for emissive (as opposed to reflective) displays are always measured under the optimum condition of a room in total darkness . In typical viewing situations, the contrast ratio is significantly lower due to the reflection of light from the surface of the display, making it harder to distinguish between different devices with very high contrast ratios . How much the room light reduces the contrast ratio depends on the luminance of the display, as well as the amount of light reflecting off the display . </P> <P> A clean print at a typical movie theater may have a contrast ratio of 500: 1, a transmissive digital projector is around 200: 1, and a reflective digital projector (i.e. DLP) is around 500: 1 under nearly ideal circumstances . A modern computer LCD monitor is typically at 1000: 1, and TVs might be over 4000: 1 . Dynamic contrast ratio is usually measured at factory with two panels (one versus another) of the same model as each panel will have an inherent dark and light (hot) spot . Static is usually measured with the same screen showing half screen full bright vs half screen full dark . This usually results in a lower ratio as brightness will creep into the dark area of the screen thus giving a higher luminance . </P>

What is the difference between static and dynamic contrast ratio