Cheaters called "pirates" often use camcorders  and cell phones to make illegal copies of blockbusters  in the local theater. These pirates then sell those recordings on the street or over the Internet for very low prices. Some share them for free. "It's unfair for people to pirate movies, " says 15-year-old Hadaia Azad Ezzulddin. Movie piracy "takes money out of the pockets of thousands of people in the movie industry," she notes. Victims include famous actors and directors as well as local theater owners and their employees. Hadaia came up with an idea that could help stop movie piracy. Hadaia's idea uses infrared  light. This range of light is invisible to the human eye. It is visible, however, to many types of cameras. Theater owners could place small infrared lights on their movie screens. The lights would not disturb people watching the movie. It would, however, distort the recordings made by many types of cameras. To test her idea, Hadaia built a box with a movie screen inside. Then, she projected images on that screen through a hole in the box. She took recordings of those images, using nine different types of cameras. These included the types found in cell phones as well as camcorders. During some tests, she also turned on light emitting diodes , or LEDs. The LEDs were embedded  in a certain place behind the movie screen. They gave out infrared light. Sure enough, she showed, a pirated movie included odd stripes or spots if it had been recorded while the LEDs were on. It might be possible to use the LEDs to flash the date and time on the movie screen. The information would then appear in the illegal recordings. Theater owners or police might use the information to track down the pirates. Cutting down on piracy might get more people into theaters to watch the real movie instead of an illegal copy. Six out of every ten films now produced aren't profitable. They don't make enough money to recover how much was spent to make and market them. Such a poor payback can discourage filmmakers from producing anything but the types expected to become blockbuster hits. It might also keep smaller theaters from showing a wider variety of movie types. Infrared lights are put on the movie screens to   _  .
adjust the brightness of the movie screens make sure the images of movies are dark protect the eyesight of viewers in the darkness make illegal copies of movies unpleasant to see