The colorist is a post-production technician who processes or corrects every image or shot by color, tint, and hue in a cinematic production to achieve the final look of the film or video alongside the lighting director and the cinematographer.
Usually, he doesn’t come until a film or video has been cut from start to end in post-production, a colorist should have a good knowledge of color theory and how colors affect human psychology, and the ability to foresee the director’s idea.