"Darkening" cast brass without changing Cu / Zn ratios

[dshore]

I have to produce a casting that is approximately 80 % Copper and 20 % zinc, but would prefer to have this casting that turns out darker in colour - more like a 95 % Copper and 5 % Zinc alloy. Could add some other minor elements, but have to keep Copper and Zinc in those ranges.

Any suggestions of how I could "darken" or "redden" (is that a word) this alloy ?

Thanks

 

[dik]

Can you try a solution of 'Liver of Sulphur'?

Dik

 

[dshore]

A patina would not work - I need to change the color of the alloy itself when cast.

 

[ornerynorsk]

Is the desire for color based on some arbitrary reason, or is it necessary to the finished part? Can you copper plate the part after any second ops are done? Would the cost difference between yellow brass and red brass or bronze be nullified by the additonal color treatment, if such a treatment exists? My 2 cents.