What is "contrast ratio" and why is it important?

Contrast is the ratio between the white and black parts within an image. The larger the contrast ratio of an HDTV (or any TV), the greater the difference between the brightest whites and the deepest blacks that TV can display. Therefore, a contrast ratio of 100,000:1 suggests that the black levels are 100,000 times darker than the white levels. But that's where it should end for most of us--unless you watch everything in the dark, don't get too caught up in big contrast numbers. They are largely there for show. The way your eye responds to contrast is really the important factor. The presence of even tiny amounts of ambient light in a room can make an HDTV display with a very high contrast ratio look similar to one with a much lower rating.  more