You
            can convert an image into a negative by applying the Invert tool.
         
         NoteYou can invert just
               RGB, just Alpha, or RGB and Alpha, see the Affects menu in Tool
               Options.
            
         To invert an image:
         
         
            - From the Tools tab, drag the Invert tool
               from the Color Correction folder to the dependency graph in the
               Schematic view. 
            
The image is inverted.