The commercial printing industry is one of the nation's largest manufacturing businesses. It is also one of the most dynamic—in terms of technological advancements and multi-level career opportunities. The actual printing is done by printing machine operators. They set up and operate many types of printing presses. Specific tasks depend upon exactly what will be printed. The press operator may install plates or adjust rollers on a machine, and loads the ink and paper. The controls are carefully set to make sure the printed product moves smoothly through all stages of the process. The operator is constantly monitoring the printing control panels and computer screens, as well as visually checking the product for continuous quality. Press operators are assisted throughout the entire production process by computers. Plates are burned using computers-guided lasers. Paper is loaded by computerized hydraulics, and then monitored. On some presses, the entire print run is monitored by dozens of computers that are making constant adjustments. In between print runs, an extensive preventative maintenance program is required to assure the highest-quality printed products. As new technologies continue to emerge, certain graphic communications functions will disappear and more advanced ones will be created. Many pressrooms are staffed around the clock – making the printing industry increasingly responsive to time sensitive needs of it’s clients in the advertising, publishing, financial, pharmaceutical, and retail worlds to name but a few.