I have a commission for a tattoo concept, they want it colored black then color then black. its supposed to be a black-rainbow- raven. I asked them if they meant coloring like a oil slick which I shown a example, but no, they really mean black, then red, then black then orange etc... I don't wanna mess this up as it's a traditional style drawing, so any tips on how to perform such coloring? examples would really help if you can, or a detailed explanation. I feel like it really shouldn't be that hard to understand what they want, but I'm a little brain fried at the moment. so in advance I'm sorry for my silliness.