Baldwin's Patina, Unlocked

One of the surprise silver linings that came along with the sad passing of Phillip Baldwin (mokume maker, metalsmith and blacksmith extraordinaire) was getting to meet his wife Layne Goldsmith. She generously shared the recipe for Baldwin's patina with me back in March and gave me her blessing to share it widely. I wanted to test it first though. Finally I've had a chance to make up a batch and I can say it works perfectly! Pretty easy to put together, and forgiving too. 
This patina will create beautiful colors on copper-based alloys - copper will be nut brown, shibuichi gray to black depending on the silver percentage, and shakudo black to purple depending on the gold percentage. The best part is that it leaves silver alone; that is how I get the great contrasting colors in my silver/copper alloy mokume pieces. It would also be great for marriage of metal work that uses these alloys. 
My recipe notes - I used 10% ammonia bought at a hardware store rather than 28%, so I doubled the amount. Worked great! I did use actual Joy dishwashing liquid, but I bet other dishsoap would work too. It gets quite sudsy when you first mix everything, but settles down afterwards. 
The photo recipe photo below is what Layne gave me, but here it is typed up, with my slight adjustments:
Baldwin's Patina
(adapted by Anne Wolf)
100 ml distilled water
20 ml 10% ammonium hydroxide
5 gr Cupric Chloride (CuCl)
2 gr liquid dish soap (Joy)
2 gr urea granules (fertilizer)

This will make enough to last most metalsmiths a decade or so. If you're not into gathering all the ingredients you can purchase a very similar product called "Ready Patina" from Reactive Metals in the US. But, if you enjoy playing mad scientist and/or live outside the US I highly recommend making some of your own; it is so satisfying. Go forth and patinate!