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Let there be light

Nov 1, 2007 12:00 AM

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To properly operate a press, we need to take into consideration the lighting of the area around the press, the color viewing area and the lighting in between the units themselves. The area around the press needs to have approximately 100-ft. candles of light to allow the pressman to see everything nearby, including dirt — a well-lit pressroom is cleaner than a poorly lit one. Place two fluorescent fixtures dropped to about 2.5 ft. over the press, placing them around the press about 1 ft. away at an angle.

For color viewing, the first step is to eliminate sunlight in the pressroom; sunlight will interfere with the viewing of color and strong sunlight can harden rollers. Most homemade color viewing booths I have looked at are very poorly done. A regular commercial viewing booth is the preferred method. In addition, the lamps should be changed every 1,500 hours. When the ends of the lamps start turning a bit dark, the color of the lamp itself changes.

For 25-inch and larger presses, lighting between the units is critical. A pressman needs to be able to see water on the non-image area of the plate. Many pressman on sheet and web presses have installed strong, shielded fluorescent lamps and, in some cases, small spotlights. When the press is stopped and the guards are lifted, a fluorescent lamp in the guard works well.

Editor's note:

Ray Prince's “Tech Thought” series appears each month in AP's New Products section. See And, don't miss his new podcasts at

Raymond J. Prince is a leading expert in pressroom technical and operational issues. He is vice president and senior consultant, operations management, NAPL (Paramus, NJ). Contact him at (605) 941-1492 or e-mail