How is contrast ratio measured?
In a very dark room, first of all. The big number on the front end (i.e. 20,000) is the light side, and the 1 is the dark side. The dark side, therefore, has a much greater effect on the ratio than the light. Cutting the darkest dark on a screen by .5 effectively doubles the contrast ratio. Which is why you hear a lot about “true black” and never about screens as bright as arc welding torches that you need shaded lenses to view.
