I always interpreted:
- Batman Begins as the Sunrise, the beginning of the day, the beginning of Batman. That's the why of the slightly desaturated golden orange. And I think Wally Pfister himself mentioned it.
- The Dark Knight as the day into night transition, the happening of day itself, also various scenes taking place during daytime. That's the why of the blue. (What color is the sky during the day, kids?
)
- Shadow Of The Bat as the Sunset, the ending of the day, the day is complete, as Batman will be (or at least "more" complete). The sunset it's known by it's intense red and orange colors. So I think it's logical for red to be the next one.
That's cool. I always felt it might be red too.