Only shakudo will patina black in with rokusho if you do it right it is a difficult patina to do but is a nice black with purple undertones from the gold.
Jim, I get the black/blue from gently torch-heating the
scratch-brushed metal. Mind you I use 10% gold 90% copper for my
spectacle alloy.
Brian
B r i a n =A0 A d a m J e w e l l e r y E y e w e a r =A0
@Brian_Adam1 ph/fx +64 9 817 6816 NEW ZEALAND