All of the halftone printing was done with a cluster of four rectangular laser spots, three long ones and a short one, with relative positions controlled to a few microns. The long ones were able to clear all the area of a pixel, 90 microns square, or any designated part of it. The short laser was used to remove small amounts of black material as needed for small density steps in the darker regions of a print. The wavelength used was 830 nm. 005