Why do weathermen and amateurs use green screens when professional movie makers use blue screens?

Question

I've seen a lot of "low budget" green screen setups. However, when I watch things about professional filmmaking, it seems everyone is using blue screens instead. (e.g. I've seen Industrial Light and Magic called "the blue screen boys", and the recent TF2 "Sentry Sabotage" video was filmed using a blue screen)Is there some technical reason for this distinction or is it merely personal preference/inertia?

Answer 1

I'm not entirely certain on this, but I believe it's for more realistic light reflections or color selection with the scene they're doing. For instance, say the players in the scene are wearing a lot of green tones in their costuming. Putting them in front of green, intending to remove the green, will make it more difficult for the rotoscope artists to remove just the green of the background and not the clothes too. So it may make more sense to use a different vibrant color to key out. In a different vein, light does tend to reflect some of the color that it's bouncing off of. This is the same principle used in bounce cards. Therefore, if the scene takes place indoors, or in the sky (as many of these sequences tend to) it may make more sense to choose a color that isn't so out of place in the scene that the light reflections cast hues on the actors. In many of the movies that are doing this now, sometimes the entire set is computer replaced later. That much green all around is definitely going to be a bit luminous. Blue is still a vibrant enough color to key out without casting as strange a hue cast on the actors and other lighting in the scene.