Display Blog: What is Brightness Contrast Sharpness and Saturation in TV exactly??

A lot of people do not exactly know the difference between Contrast and Sharpness or Brightness and Saturation in TV usually. Moreover, these terms are very confusing and misleading when the display technology changes. For example brightness in LCD display is a complete different mechanism compared to a Plasma display or LED based LCD display. So let me walk you through the basics of these terms in different display systems.

Brightness in LCD is setting the "Black" level of the display. Increasing the brightness causes the black level to be greyed which causes the color channels to be washed out. While Contrast in LCD is setting the range between "Black" and "White" level of the display.

Since LCD is not a self-illuminating display system brightness in LCD is amount of light allowed from backlight. Increasing the amount of brightness causes the liquid crystal shutters to open widely causing high leakage light between adjacent pixels. So "black" level gets greyed out due to back light leaking from the liquid crystal channels. This has an adverse effect on color saturation of the display also since colors no longer can be displayed "pure" due to leakage.

Contrast on other hand stands for the "gamma curve" of the display. Usually the gamma curve is a logarithmic function and typical value is 2.2. But this value can change depending upon the type of display. For OLED the value of gamma curve can be anywhere between 2.0 ~ 2.4. Contrast adjusts the ratio of "white" and "black" levels of the TV. Increasing the contrast causes more levels of grey shades between pure black and pure white. Thus increasing picture quality for color images since more detailed color levels can be displayed.