16-bit color
From The Glossary of Digital Photography
A color system in which each pixel is represented by 16 bits. These bits are broken down into 3 bytes; each byte represents one of the three primary colors: red, green, and blue (RGB). There are 5 bits, 6 bits, and 5 bits assigned to the 3 bytes. On PC computers this is called high color, on Macintosh computers it is called thousands of colors. The actual number of colors available with 16 bits is calculated by looking at each color, which is represented by 1 byte, which has 5 or 6 bits; this translates to 25, or 32, colors for each of 2 bytes or colors, and 26, or 64, for the third byte or color. Since there are three colors, there are 65,536(i.e., 32 x 64 x 32 = 65,536) colors available for each pixel. The reason that the color green is typically chosen for the extra bit is that the human eye is most sensitive to the various shades of green. 24-bit, or millions of colors, is more common today. See also 24-bit color
