Contrast ratio is the difference between light and dark on a screen expressed by a number. If you take the brightest white on a screen and the darkest black and compare the luminosity, you will get the contrast ratio. For example, a 1000:1 contrast ratio means that the brightest white is 1000x brighter than the darkest black.
Therefore, a high contrast ratio means the projected image will have incredibly rich, crystal-clear detail. Contrast is especially important for the home theater, where ambient light might otherwise prove it to be challenging to see rich cinematic content if there is not a significant enough difference between whites and blacks.
Epson's exclusive Vertical Alignment (VA) LCD technology provides an opaque black to be the natural state, allowing a projector to achieve astounding blacks with a contrast ratio up to 200,000:1.