I discovered this superb book in 1987 when training at Christchurch Polytechnic. It is the best in its field.
It has very clear explanations on how to patina a range of metals. I tried a range of them when I was blacksmithing and also on some of my student jewelery and bronze castings. Most memorable was the range of colours possible on copper.
The Colouring, Bronzing and Patination of Metals was written by Richard Hughes and Michael Rowe, published by Thames and Hudson and is available from Amazon. The local public library and the Polytech library both hold copies.
We have a good FX lab setup now, so it should be possible to try out many of these recipes on upcoming projects.
I would also like to patina some of the hand tools - to make them look really cool.