One of the most heavily advertised statistics for LCD flat-screen televisions is the contrast ratio. Usually made up of improbable numbers, they purportedly reflect the difference between the brightest white that a set can display and the darkest black, with a 1,000,000-to-1 set showing whites that are a million times brighter than blacks, and a 10,000-to-1 set showing whites that are 10,000 times brighter than blacks. However, between the fact that contrast ratios aren’t measured consistently across brands and that the eye perceives a 1,000-to-1 contrast ratio, which is less than any new LCD TV, the statistic is meaningless, so there’s no magic, good number. Another factor is that your eye responds to changes in brightness differently from display devices. Your TV is a linear device, so if you increase the light by a given amount, the image gets brighter by an equal amount. Your eye is logarithmic, so the brighter that an image gets, the more light it will take for your eyes to perceive a brightness change. For example, when you read a book in bed under a small light, you see the black text on the white paper almost exactly the same way you see it when you read on a beach on a sunny day, even though the light on the sunny day is hundreds of times brighter. Writer Bio
