Ever since the days of digital film processing, cinematographers have had free rein to recolor their shots in any way they like, without the hassle of chemical developing systems from the old film days. The Coen Brothers' Oh Brother Where Art Thou was the first Hollywood film to use this process, giving the film a washed-out yellow hue reminiscent of the films Deep South setting.
So what did Hollywood do with this new power and flexibility with color? It made just about everything orange and blue. (The idea is that orange flesh tones pop against blue backgrounds — follow that link [h/t @outwardfacing] for lots of examples.) To prove this, Edmund Helmer (a data scientist at Facebook) used Python to extract the color spectrum from movie trailers, and then used R to plot a histogram of color intensities from all the films:
As you can see, the trailers are mostly orange and blue. Helmer also created an interactive Protovis chart that allows you explore the color spectra of individual films. Follow the link below to check it out.
BoxOfficeQuant: Oranges and Blues