24-bit color
From The Glossary of Digital Photography
A color system in which each pixel is represented by 24 bits. These bits are broken down into 3 bytes, where each byte has 8 bits and represents one of the three primary colors: red, green, and blue. On PC computers, this is called true color and on Macintosh computers it is called millions of colors. The actual number of colors available with 24 bits is calculated by looking at each color, which is represented by 1 byte, which has 8 bits, thus there are 28, or 256, colors for each byte or color. Since there are three colors, there are 16,777,216 (256 x 256 x 256 = 16,777,216) colors available for each pixel. It is more common in usage today than 16-bit color. See also 16-bit color
