Halftone refers to a reprographic technique that will give you the appearance of a continuous tone by using all dots. The dots can vary in size, shape, or spacing, but the entire image is made up of dots. With the Halftone effects in Pixelmator, you have five different types of Halftone effects you can apply, namely, Circular, Hatched, Line, Dot, and CMYK. You can use these to create texture over your images or to create backgrounds.