Halftone
A printing method that shows shades of a colour using dots of different sizes.
Also: halftone screen, dot screen
A printing press can only print solid ink or nothing. To show greys and soft colours, the image is broken into a grid of dots. Where the picture is dark the dots are large and nearly touch; where it is light they are small. At reading distance the eye sees a smooth tone. Look at a newspaper photograph under a magnifier and the dots are plain. Colour pictures use four overlapping grids, one per ink, each set at a different angle so that the dots form small rosettes instead of blotchy patterns.