I have a bright living room and a dark hallway that share a wall, flows seamlessly from living room to hallway. I want a white/gray color for the hallway but a little more substantial gray for the living room. Anyway to do that? Is there a way to gradually change a color or if I used like a 50% lightened version of the color I chose for the living room?? Wasn't sure if it could be like.... Feathered in or something. Thoughts??