Electrostatic and thermal plotters have more in common with dot matrix printers than with pen plotters. As such, they are discussed first. Electrostatic plotters can produce multi-colored images. Pen plotters are commonly categorized according to the way in which the pen is moved from point to point on or above the paper. Flatbed plotters hold the paper motionless on a flat bed while a pen is transported in all directions to create the image.
Some models are able to produce multi-colored images by automatically changing pens.
Some also provide the capability of writing on a variety of media by allowing the use of various types of pens. Drum plotters lay the paper across a drum that rotates forward and backward as the pen is transported back and forth perpendicular to the motion of the drum to create the image. As in the case of the flatbed plotter, some drum plotters can produce multi-colored images and write on a variety of media by allowing pen changes. Because all softcopy output devices produce visual output, their important characteristics are associated with their visual presentation capabilities. In most cases, bigger is better - and more expensive.