Creative Effects > Colour Corrector > Colour Corrector Settings >
Inverting the Matte

You can invert the matte clip. Inverting the matte swaps the transparent and opaque areas of the matte and redefines the area of the front image that can be colour corrected, as well as the area of the back image that is shown.

To invert the matte clip:

1. Click Setup in the Colour Corrector menu.
2. Enable Invert Matte.