Secondary colour correction

Primary correction sets exposure, white balance and contrast across the image. Secondaries then isolate a region using a qualifier that selects by hue, saturation and luminance, or a mask that can be tracked to follow movement, and adjust only what falls inside it.

Typical uses are calming a red face, holding a sky while the ground is lifted, matching a product to its brand colour, or draining saturation everywhere except one object. The failure mode is a visible edge or a halo where the selection ends, and a soft key with a little blur on the mask exists to prevent exactly that.