The pixel depth, that is, the binary sum of all color components of a pixel, determines the maximum number of different colors. For example, if the pixel depth of a monochrome image is 8 bits, the number of different brightness levels is: 2 8 = 256; Another example is the color image composed of RGB primary colors. If the number of pixels in the three components is 4, 4 and 4 respectively, the pixel depth of the image is 12, and the number of different colors is 2 (4+4+4) = 2 12 = 4096.