"What David wanted to achieve was to help the story, and create an atmosphere. Coloring is to the image what sound design is to sound — all these little things that you can hear, or you can see, but are not in your face. For example, we played a bit with the sharpness. When the action is a bit violent, when Hayley attacks Jeff, we used a lot of sharpness to make the image very aggressive."
http://www.studiodaily.com/filmandvideo/currentissue/6312.html
Click her for: