Interesting article about the technology behind the 4- and 5-bladed disposable razors.
Down the hall from the high-speed video lab is the room where they do three-dimensional motion analysis using infrared cameras: "It's the same system they use in some of the latest blockbusters, like Spider-Man or Lord Of The Rings." The changing positions of markers that reflect infrared light are triangulated by the cameras, so the movements of the razor and the shaver's arm can be recreated in a virtual 3D space on a computer. "The way in which you hold that handle and you rotate that handle, if you watch men do it, it's quite amazing. You think they could all be cheerleaders," Stewart says. High-speed infrared cameras, running at around 2,000 frames a second, are also used to measure skin deformation and strain. A similar technique is used in the car and aeroplane industries, though Gillette have patented it for shaving research. Next door, sensors in a specially adapted razor measure the forces different men put on it while shaving.
(via justin blanton)
