Contrast Ratio 101

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What is contrast ratio?  What is the best contrast ratio?  Why does it matter?  These are valid questions, especially when shopping for a new TV.

What is Contrast ratio?

Contrast Ratio is simply a comparative measurement of lumens (lumens is a measure of light output), comparing the amount of lumens output by a pixel on a TV when it is darkest (black) and brightest (white).  In lamens terms, contrast ratio is simply two numbers that show how much brighter the TV is at its brightest compared to how bright the TV is at its darkest.  If the contrast ratio is 1600:1, it means that the manufacturer of the TV set claims that their darkest black is 1600 times blacker than their brightest white.

Why Does Contrast Ratio Matter?

Contrast ratio is basically a technical term for how realistic the colors and brightness is, pretty much determining how realistic in general the picture is. TV sets with extraordinary contrast ratios for instance will display a really dark looking night sky, while ordinary contrast ratios typically will show you a washed-out black where it should be pitch black.

Static or Dynamic Contrast Ratios?

If you want to get more technical and accurate, you'll want to test for both Static and Dynamic contrast ratios.  Since the television you are planning on buying will perform differently in real life applications than it does in a testing lab with optimal conditions, the Static and Dynamic contrast ratios will often differ.  A Static contrast ratio is the biggest possible difference of black and white lumen output in seperate, unrealistic tests, while Dynamic contrast ratio is more realistic contrast ratio in an average viewing experience.  Since static contrast ratio is usually a more impressive number, this is the figure that you will most often see when researching the television.

Are Contrast Ratio Numbers Reliable?

A high contrast ratio figure is one spec that manufacturers know will sell more TVs, but can they actually lie?  They probably won't lie, but they probably will use different techniques to measure contrast ratio that will inflate their numbers.  Unfortunately there is no standardized method that manufacturers are required to follow yet.

Contrast Ratio Measurement Test 1 - Full On/Full Off: Basically, the television is tested with consistant parameters in either a fully lit room, or a room with virtually no light, and tests of brightness and darkness are done seperately.  This is considered the recommended test for dynamic contrast ratio.

Contrast Ratio Measurement Test 2 - ANSI contrast: In this test, a black and white checkerboard is used and the bright and dark limits are tested simultaneously.  This test is the recommended test for static contrast ratios.

Contrast Ratio Measurement Test 3 - Mix of 1 and 2: Some manufacturers of projectors or TVs will use a combination of these two tests in different phases of testing to inflate their contrast ratio.  So although this isn't necessarily out-right lying, they are not being very truthful either.

What is the best Contrast Ratio Available Today?

There have been a number of break-throughs recently with contrast ratio, and who knows how long this will last, but recently there have been OLED (Organic LED) televisions manufactured by Sony and Samsung that claims to reach 1,000,000:1 contrast ratio.  OLED screens, although they haven't achieved the same size as LED or Plasma screens, have an advantage in contrast ratio because each pixel is an independent light.  This is in contrast to LED screens where there is one main light, and each pixel has to shine that light through a universal plastic, which can wash out a the TV's contrasting abilities.

There are new TVs using a technology called SED (surface-conduction electron-emitter diode) that have already achieved sizes past 55" and claim a contrast ratio of 100,000:1.  Plasma screens have also reached this level of contrast ratio, but suffer from other maladies like screen-burns and a high ticket price.  LEDs are less capable of as high of a contrast ratio, but still impresses me with 30,000:1 units almost becoming a norm (I'm overly impressed with my 6000:1 Vizio 32" LCD).