Although I flip-flop between ghost signs and rock art, I use the same photographic and enhancement techniques for both.
This example is a well-known location in Dinosaur National Monument. The two enhancements emphasize different things. The first brings out details such as the texture in the “flower pot”. The second emphasizes the scratched vandalism. The second example is from the Rock Art site south of Rangely, Colorado. This example of Barrier Canyon style painted rock art is both faded and vandalized. The enhancement emphasizes the red pigment and minimizes the scratches.