OK, and this is true probably of all metals, but I discovered this with Vintaj natural brass, and it looks FAB on the brass and boy, I"m rambling!!
Here's the deal, you can paint the stampings, with acrylics and with alcohol inks! I love the inks!! They come in 20 + colors, and they work so funky.. because they are alcohol based, they don't blend, they sort of "chase" each other as you add another color, so you can get incredible effects. It makes me think of tie-dye really. To intensify the color and seal it, you can use resin or resin like products. Here are three of the color projects I've worked on in the last month.
These earrings are one of the first projects I did, to test out the inks. ( I bought a 3 pack of inks to try out... now I have 21 colors!!) It's hard to see in the pics, but I used a stamp and ink pad to add black swirls in the background, let them dry, and then dabbed acrylic paint on 3 corners for texture. Then I started adding the inks. Finally I sealed it with glossy accents, which is a very fast drying resin like product. (not sure I would recommend for projects you need a good dome on, but for fast and dirty, it works great!) Now the colors I used didn't exactly turn out to be the colors I ended up with, but it looked really Autumn-ly to me, so I used black, orange and tourmaline colored crystals to accent them.
This pendant started out as a blank . This was pure color experimentation. I used a combination of acrylics and alcohol inks. I let it dry, then I added a pearl ink on top.. very fun! it bubbled up and mixed everything up! Then I sealed it in, again, it looks very little like it started out as. I topped it with another Vintaj piece, and added crystals in matching colors with Sterling wire. I think it turned out stunningly!
This pendant is "U are are the key to your dreams" . I used metal stamps to make the words on a blank, and another Vintaj piece shaped like a key instead of the word. I used again a combination of paint and inks, and sealed it. Now this took longer to dry, as I layered the sealant much heavier as I was "gluing" the key to it. Added a large, heavy ring as the bail. There is a really delicate color effect on this one.