This helps reduce or hide image artifacts and flaws in the original film material. It is important to understand that post-processing always involves a trade-off between speed, smoothness and sharpness.
The post-production phase of creating a film usually takes longer than the actual shooting of the film, and can take several months to complete because it includes the complete editing, colour correction and the addition of music and sound. The process of editing a movie is also seen as the second directing because through post-production it is possible to change the intention of the movie. Furthermore, through the use of color grading tools and the addition of music and sound, the atmosphere of the movie can be heavily influenced. For instance a blue-tinted movie is associated with a cold atmosphere and the choice of music and sound increases the effect of the shown scenes to the audience.