[pwr]

Beautiful colors indeed. I've occasionally gotton similar just with very gentle and controlled heating, but those are then oxides, not sulphides, so pickle will remove them. Your sulphide patina is more stable. I used to get something similar, years ago, while applying patina to 24K Keum-Boo applied over silver with a subsequent roll print texture. The gold foil is thin enough that some silver diffuses up through the gold, enough so that the gold can take a slight patina even though it started as 24K. The gold color isn't yet affected, yet you get these wonderful purples, just as you've got. But that takes a stronger LOS solution, perhaps due to less alloy. On the other hand, a couple pieces of that work I've still got around here someplace, still have the same color, almost 20 years later. It didn't darken over time. As to needing your own alloy, I'll bet it's the absence of zinc or other deoxidizers in your own alloy that are the difference between yours, and the commercial stuff. Also, it might be that most commercial 14K alloys have less silver than copper, so the relative greater reactivity of the copper might make it less likely to get the good colors, and more likely to just turn dark. Just a guess.