The Chromatic Aberration tool emulates the look of misprinted film or poor quality lenses by shifting the red, green and blue channels. This tool can also be used to correct for minor chromatic aberration problems in the original image.

Red/Cyan, Green/Magenta, Blue/Yellow: Scales each primary color and its opposite from the center. For example, the Red/Cyan control scales Cyan to the right and Red to the left around edges with positive values, and scales the opposite with negative values in the same control.