While green is the modern standard, 'Blue Screen' was the king of Hollywood special effects for over 50 years. The first major use of the 'travelling matte' blue screen process was in 'The Thief of Bagdad' (1940), which won the Oscar for Special Effects. Larry Butler, who developed the process, used the blue background because it was the furthest color from human skin tones in the three-strip Technicolor process. This allowed filmmakers to 'sandwich' two pieces of film together—one of the actors and one of the background—to create effects like flying carpets. It wasn't until the digital revolution of the 1990s that Hollywood switched to Green Screens, because digital cameras are more sensitive to green, allowing for a cleaner 'key' with less lighting power.