Web Design in a Nutshell, 3rd Edition

Truecolor

PNG can support 24- and 48-bit Truecolor images. The term “Truecolor” refers to the full color range (millions of colors) that can be defined by combinations of red, green, and blue (RGB) light on a computer monitor (see Chapter 28 for more information). Truecolor images do not use color tables and are limited only by the number of bits available to describe values for each color channel. In PNG format , each channel can be defined by 8- or 16-bit information. It should be noted that 48-bit images are useless for the Web. Even 24-bit should be used with care (JPEG usually offers smaller file sizes with acceptable image quality).