Secondary color correction

Primary color correction, or grading, is applied to the whole image. Secondary correction is applied only to selected areas of the image, the area being defined by a pattern generator (e.g. a circle or rectangle), by curved lines or derived from the object itself using chromakey techniques or any combination of all these. This way, for example, the color of a car in a clip could be changed from say, red to green, while the rest of every image is unchanged.