I just finished painting two garage doors and surrounding trim to look like patina copper. One was a double and one a single car door. When I started both doors where painted the color of the house so the first thing I did was to paint the doors the color of copper that has been aged which is a dark reddish brown.
Then I start the patina process by painting on the first glaze coat of patina color.
Here is a picture of the door done but not the trim and then the next picture is a close up then a close up in the same area with the trim painted.
The completed doors.