With
            some images or clips, you may need to perform selective colour correction—where
            you modify a range of colour, as opposed to the entire clip or image.
            Use the tools in the Selective menu to create selectives. Selectives
            are generated mattes used to isolate colour ranges for selective
            colour correction.
         
         In the Selective menu,
            you can: 
         
         
            - Create and refine a matte using tolerance
               and softness to define the range you want to modify.
            
- View a matte, a selected colour range,
               or the result.
            
- Enable mattes to apply the selective
               colour correction to the result image. Disable mattes to remove
               the selective colour correction from the result image.
            
TipSet the image window
               to 2-Up view (Alt+2) so that
               you can create your matte in one viewport while simultaneously monitoring
               the result in the other.