This is one example of a tray ceiling treatment. This tongue and groove board slides together and the boards are nailed to the ceiling in such a way that the nails are not able to be seen. This treatment is a very commonly used method to make a tray ceiling stand out. The ceiling can then either be stained or painted based on your personal preference. With this treatment, crown molding is also commonly run around the border of the tray ceiling to give it extra depth.