Most printers (e.g., dot-matrix, ink-jet, laser) produce only binary output -- at any point on the paper addressable by the printer, either the printer prints a dot or it doesn't. Thus the printer cannot produce intensities between black and white at a single point, so it is not possible to print a continuous tone image directly to such a printer.

However, using an image operation called halftoning, the printer can produce the appearance of intermediate shades of grey in a local neighborhood of several pixels. In this lab your will learn about two methods for halftoning. The first part of the lab examines the use of the dithering matrix, and the second part is on error diffusion.

As always, read each web page for this lab carefully, including the notes page.