How to blacken nickel-silver?

[Dmitry.M]

I'm looking for how to make it. Found a lot recipes, but not about nickel-silver alloy.
Need to make it at least dark-grey. Any ideas?

 

[Shakudo]

why do you want to make the patina solution? nickel silver is just a white brass,so any brass oxidizer will work. or any gun bluing solution containing selenium.

 

[mete]

Nickel silver [german silver] is an alloy of copper, zinc, nickel .It does NOT contain silver. Those elements all form sulphides which are black. I haven't ever tried selenium solutions but selenium is very similar to sulphur .