Patinas on brass stampings

I have been working on patinas on brass stampings for a client who didn't wish for a gold look on the brass.  These are raw and have not been buffed but it was informative to work on.  Having three of each allowed me really show the experimentation.

The salt and vinegar, no not potato chips, but cider vinegar and salt in a ceramic dish, letting the brass soak for about 20 minutes and then baking it for 20 minutes at 450 degrees gave a beautiful coppery color,  Suspending the brass in a glass jar above an inch of ammonia but not touching it,  really darkened the color.