So many opinions - so much misinformation. I have used a Thomas Duplex Safe Light in my darkroom since 1982. The safe light comes with two sets of filters. One for use with black and white paper, and the second set is added on top of the B&W paper filters with the vanes closed for color paper (RA 4 process). The safe light is installed by hanging it from the ceiling. The light is aimed at the ceiling and reflected off of the ceiling. By opening and closing the two safe light filter vanes (or doors) you can adjust the illumination level in the darkroom. Since the light is reflected from the ceiling, the safe light is, in effect, the distance from the safe light to the ceiling, plus the distance from the ceiling to the printing paper - meaning, if you have a standard (in the U.S.) eight foot ceiling in the dark room, the the safe light is hanging about 1-foot below the ceiling, the light has to travel at least 8-10 feet to the B&W paper. This makes the intensity of the light far less than a standard bullet safe light aimed downwards. In the entire time I've used the safe light, I have never had it fog any paper I've used that includes; Agfa, Kodak, Ilford, Seagull, DuPont, and Forte. As a test, I've put a piece of Polycontrast Rapid paper, Portriga Rapid, Kodabromide, and Varilour out on the enlarger easel with another piece in the processing sink with 1/2 half of the paper covered to block the light. I left the paper illuminated by the safe light for 30 minutes. No piece of paper was fogged by the exposure to the safe light. The idea that the safe light cannot be used with fast B&W paper is ludicrous and pure speculation as, in the 35 years I've used my Thomas Duplex Safe Light - no piece of B&W paper was fogged regardless of the manufacturer, whether the paper was multi-contrast or graded paper, and MORE IMPORTANTLY regardless of the paper's shadow speed. Further, there is NO NEED to switch the safe light ON / OFF. You leave it on the entire time you're in the darkroom as it will not fog B&W paper. In use, I have the vanes on my safe light opened about 1/4 inch, with most all of the light going through the B&W filter on the safe light. This provides a nice, low overall illumination for the darkroom. For developing the paper, I have Kodak bullet safe lights over the sink with OC filters in them. I turn these safe lights ON / OFF as needed for processing the paper. Please, just stop with the misinformation. If you've never used the piece of equipment, you have no reason to speculate about its operation since you have absolutely NO idea what you're talking about.