A technique that assigns a color to each grey level of a monochrome image, helping visualize patterns of intensities.

The distinction between true color and pseudocolor has to do with the design of a monitor's frame buffer. If the frame buffer uses 8 bits per pixel to store color information, the monitor can display 256 colors simultaneously. What you see on such a monitor is called pseudocolor because the colors that can be shown at any one time are a small subset of the colors the eye can distinguish. If the frame buffer uses 24 bits per pixel to store color information, your monitor can display over 16 million colors (true color). Pseudocolor is sometimes called indexed color because the values stored in the frame buffer on a pseudocolor system are not the RGB values needed to drive the red, green, and blue electron guns in a monitor. Rather, they are indexes into a colormap, or color lookup table, which stores 256 sets of RGB values.

Another name for palette-based images, also known as colormapped or indexed color. In contrast, an RGB image is known as truecolor. (Grayscale images are simply grayscale.)