perform in near darkness Flying spot cameras tend to work unreliably outdoors in daylight In 1928, Ray Kell from the United States' General Electric proved that flying spot scanners could work outdoors. The scanning light source must be brighter than other incident illumination. Kell was the engineer who ran a 24-line camera that telecast pictures of New York governor Al Smith. Smith was accepting the Democratic nomination for presidency. As Smith stood outside the capital in Albany, Kell managed to send usable pictures to his associate Bedford at station WGY, which was broadcasting Smith's speech. The rehearsal went well, but then the real event began. The newsreel cameramen switched on their floodlights. Unfortunately for Kell, his scanner only had a 1 kW lamp inside it. The floodlights threw much more light on Governor Smith. These floods simply overwhelmed Kell's imaging photocells. In fact, the floods made the unscanned part of the image as bright as the scanned part. Kell's photocells couldn't discriminate reflections off Smith (from the AC scanning beam) from the flat, DC light from the floodlamps. The effect is very similar to extreme overexposure in a still camera: The scene disappears, and the camera records a flat, bright light. If used in favorable conditions, however, the picture comes out correctly. Similarly, Kell proved that outdoors in favorable conditions, his scanner worked. Larger videos A few mechanical TV systems could produce images several feet or meters wide and of comparable quality to the cathode ray tube (CRT) televisions that were to follow. CRT technology at that time was limited to small, low-brightness screens. One such system was developed by Ulises Armand Sanabria in Chicago. By 1934, Sanabria demonstrated a projection system which had a image. Perhaps the best mechanical televisions of the 1930s used the Scophony system, which could produce images of more than 400 lines and display them on screens at least in size (at least a few models of this type were actually produced). The Scophony system used multiple drums rotating at fairly high speed to create the images. One using a 441-line American standard of the day had a small drum rotating at 39,690 rpm (a second slower drum moved at just a few hundred rpm). Aspect ratios Some mechanical equipment scanned lines vertically rather than horizontally, as in modern TVs. An example of this method is the Baird 30-line system. Baird's British system created a