spectacular speculations.

Jean-Clement Soret was the digital colorist for the film, and is one of the few instances where a colorist received a spot in the opening credits. The film contains many coloring effects and “density shifts” of lighting to reflect the moods of the characters. For example, when Hayley gets angry the colors would be edited to be of lower frequency. One effect used which, as far as the director is aware of, had not been done in cinema before, was to brighten the lighting in filming and recorrect everything down in post-production. This allowed for facial details to be visible even while having a darkened atmosphere

(Source: filmtrivia)