HDTV displays, whether they be LCD or plasma, are all composed of large numbers of pixels. The number varies with the HDTV’s resolution which is a measure of the number of horizontal rows and vertical columns of pixels.

Each pixel is made of three individual green, red and blue (RGB) subpixels. A display’s electronics control the intensity of each subpixel to mix an overall color for that pixel. The number of discrete levels of intensity with which each subpixel can be varied corresponds to the bit-depth of each subpixel color. A single 8-bit subpixel can produce 256 (2*8) discrete levels of intensity and a 10-bit subpixel 1024 (2*10) discrete levels. The combination of variations of intensity levels of individual green, red, and blue subpixels within a single pixel enables the reproduction of (256)*3 = 16,777,216 and (1024)*3 = 1,073,741,824 for 8-bit and 10-bit displays respectively. This translates to an increase in the number of reproducible colors by 64 times from an increase of 2 bits per subpixel bit-depth increase from an 8-bit to a 10-bit display panel.

Professional displays have been produced with bit-depths ranging up to 12 or 16 for some time. The larger palette of available colors means smoother transitions from color to color and a more realistic reproduction of real life colors (ie. more lifelike).

Aside from this quantitative improvement, one must also consider just how many colors the human eye can perceive. Various sources rate most of us as having an ability to distinguish some 1 to 10 million different shades of color. The exception is some 2 to 3 percent of the world’s women who are tetrachromats having another type of cone cell on their retina enabling them to perceive the world from a base of four distinct colors as opposed to the usual three. Tetrachromats have been estimated to see some 100 million different colors.

So, while a deeper bit depth does improve transitions and color reproduction accuracy it must be balanced with an appreciation of what our eyes are capable of perceiving. In the end, the perceivable benefit varies from individual to individual and should be determined with a side-by-side comparison.

Resources

Color Me Human (PDF)

Color Discrimination

Color Vision: One of Nature’s Wonders

Wikipedia – Pixel