Three Plus Five Makes Eight: A Simplified Approach to Halftoning

Abstract

We wish to represent a halftone picture on a digital device like a laser printer. One cheap and effective way is to trace a space filling curve over the picture, accumulating colour density at each pixel. When the accumulated density is high enough, we draw a dot.

We present a simple, robust and practical way to do this. Our tests have shown that the way the colour density is scaled is important and the choice may be different for natural and synthetic images. The same algorithm gives us a way to represent colour pictures effectively on cheap displays with few available colours.