(
Image processing and
computer graphics:)
The process of converting an
image to use a very small number of predetermined
pixel types, by forming patterns of these pixels. For instance, given
red and
blue pixels, we can generate
magenta-like areas in the output image by placing red and blue pixels next to each other.
The most common type of dithering represents a black and white image with just 2 pixel types: black and white. This is useful for printing out the image.
Newspaper images are usually also printed using just black and white dots; however, the process there is an analogue (non-computerised) process known as halftoning. The results there are usually similar to ordered dithering, but with a rotated halftoning screen.