One of the projects in the Metal Clay Masters Registry program is a patina study. I've been working on this for some time- researching patina methods through te ages for silver and copper, particularly; then applying what I'd learned to a variety of polymer clay techniques.
Patinas are funny things - bury a piece of shiny silver in your kitty litter box and leave it for a week and you get a lovely multicolored patina (back in the middle ages, they used horse stalls or the floors of cow byres, but not many jewelers have access to those these days). you can't really control how the patina builds on your piece of silver. You could keep digging it out and checking, but the process frequently does past the stage you want it while you're not looking. And then there are the surprises - sometimes felicitous-sometimes disastrous. Most can be recovered from with a bit of heat or friction. But the outcomes are not always what one anticipates.
it's rather like the surprises one finds in personal relationships - discovering that the super cool old friend you haven't seen in 20 years is now competing in scrabble championships when you expect him to be still racing at Le Mans or Limerock - after all, Newman was still racing at 80 - or still leaping tall buildings in a simgle bound.
well, silver and copper both react to a variety of chemicals, sometimes with unexpected consequences. and then there's added spice of mixing the metals, the chemicals and a bit of electricity... that's my latest tangent. After taking a class on electroforming on glass, I'm fiddling with the hardware, paints, acids and silver. The worst that will happen is that I'll waste some chemicals and have to clean some silver. It's a step back for me to that High School chem class where you looked at your partner and asked "how about we try this while the teacher is out of the room, just to see what happens?" Let's just hope we don't get the same result - they won't be evacuating the school this time - I'll be grabbing the cat and making a run for it out of my house.