Texturing Walls Graffiti

Here is the finished render of my street wall. I have mapped a piece of graffiti onto the wall. To do this i used a layered shader and the alpha channel I made in photoshop to tell maya which bits of the graffiti layer should be transparant and which shouldnt so that the colour attribute would be on top of the wall. Then I mapped the same bump map from the wall onto the graffiti so that bump detail from the wall is visible through the graffiti. I also used the graffiti image to create a specular map for the wall, keeping the silver spray paint with larger specular highlights and the dull brick wall with only a few. I then used a layered texture to add a colour ramp to the wall and pavement so it gets darker where the two surfaces meet. No new lighting has been added so its just a simple directional spot light which I havent changed any of the settings on.