36-bit color
From The Glossary of Digital Photography
A color system in which each pixel is represented by 36 bits. These bits are broken down into 3 bytes, where each byte has 12 bits and represents one of the three primary colors: red, green, and blue. The actual number of colors available with 36 bits is calculated by recognizing that each color, which is represented by 1 byte, which has 12 bits, which equates to 212 (or 4096) colors for each byte or color. There are three colors, so by multiplying 4096 x 4096 x 4096, a total of 68,719,476,736 (over 68 billion) colors are available for each pixel. 36-bit color is often used in better-quality scanners and digital cameras that have raw format. The 12 bits for each pixel are usually represented by 16 bits, with the additional bits not used.
