It's a tool directors use to control color in their films. Although a director could probably use a simple color palette, Pixar takes it to the maximum!

A color script defines the lighting and color palette used in an animated movie. This needs to be done because of the number of animators who actually work in parallel on such a movie, in separate locations around the globe and the desire to keep the look and feel consistent. A color script takes those definitions and expands on them by providing a rendered/filled storyboard (or more accurately, frames from the story board) that show what the look is supposed to be like. There's a science wrt choosing color schemes in a movie, to make the movie visually more attractive and provide psychological assists, and how designers use complementary pairs in a movie's art design: http://www.slashfilm.com/orangeblue-contrast-in-movie-posters/

I'm waiting for Hollywood to get bored of blue/orange :-), until then I'm relying on Pixar for color fun. Fantastic observations from Danny (color part of toolset) and Pliny (fascinating how much thought and planning goes into color). I love color, topic of my first science fair project. 7th grade, super lame, but it had a rainbow! And a prism! Heh. (Year after that, geometry! In nature! Incredibly lame photos of shells and cut grapefruits, but the geometry and the nature made it awesome). Color rocks. Just like B/W photos are more impactful when full monochromatic spectrum included, and a story/movie is more impactful when the full emotion spectrum is included, might well be stories/movies more impactful when all colors included. King of color, Shingenobu Kobayashi. The heart of his findings, in two charts, our associations and the colors. Look anywhere in our lived environment, especially stores (marketers keep up with this stuff) and you'll see examples.