This is what I'm doing: From the Ribbon, Manage>Materials>Masonry-Brick>Duplicate>Rename>Library>Masonry>Brick>Running-Red>Make it a Property Set>Generic>Colour, Select Colour, OK. Then I edit the wall type to make sure the exterior finish layer is the named the same as the newly created brick colour. And the brick colour doesn't change in my model. What am I doing wrong? Or is it even possible to do it this way - I'm thinking that I'd have to duplicate the material image file and then adjust the color in Photoshop. But then why would Revit provide a colour picker tool.