Is there something special about a chromakey background? I understand that it's like the blue screen that movie studios use, but I'd like to know why it's better than, say, a solid painted surface or a solid color muslin. Do software programs such as Photoshop pick up the chromakey blue or green better than they do other shades of blue or green? I've read a lot about using chromakey paint/backgrounds, etc. But nothing that explained why chromakey is better than other backgrounds.