What is the difference between contrast ratio and dynamic contrast ratio?

Faced with several different models of televisions from various manufacturers, the contrast ratio is one of the most important factors to consider in making your decision. A contrast ratio is defined as the difference between the lightest color and the darkest color the television is capable of producing. Basically, higher contrast ratios should yield more vibrant whites and deeper blacks. However, there are several important factors to consider when comparing contrast ratios: whether the contrast ratio is static or dynamic, and what effect your room will have on the visible contrast ratio.

A static contrast ratio is the contrast ratio at a given point in time. Imagine pausing a movie and establishing the contrast ratio at that particular frame. Plasma televisions usually have vastly superior static contrast ratios to LCD flat panels. A dynamic contrast ratio is the overall contrast ratio the television can produce over time. Most LCD manufacturers now advertise dynamic rather than static contrast ratios, which often surpass Plasma TV's static ratios.

Static and dynamic comparisons each have their pros and cons. A high dynamic contrast ratio is preferable for prolonged scenes that take place in dark settings or black and white movies in general. A static contrast ratio offers superior performance when there are sudden transitions from a well lit atmosphere to a darker one, and vise versa.

For Plasma Televisions
» Static Contrast Ratio of 5,000 : 1 or a higher

For LCD Televisions
» Static Contrast Ratio of 1,000 : 1 or higher
» Dynamic Contrast Ratio of 10,000 : 1 or higher

However, contrast ratio should never be your sole decision making factor. Firstly, most manufacturer's have slightly different ways of measuring contrast ratios. Secondly, contrast ratios are always measured in ideal viewing conditions (essentially, a pitch black room.) Depending on the lighting conditions in your room, your visible contrast ratio will generally be much lower than the manufacturer's claims. In short, a contrast ratio is a useful although imperfect benchmark for comparing different televisions, but it should never be used as a sole consideration.