There are a few different techniques you can use. I’ve washed both inks and paints over metal, and I’ve also mixed up colored metallics with Vallejo’s metallic medium. I think if you want to stick with ink washes over silver, you can use ink mixed with Future floor wax to get a more even coat. Conversely, if you want to lower an ink’s surface tension you add a drop of diswashing liquid to make it flow better into cracks and crevices. The ink technique can generate some nice effects. I do suggest diluting them wih a bit of water to lower the intensity. You can also add some liquitex or other matte medium, but I tend to use those only with glazes and washes where I want to carefully control the blending. As I said, there are a lot of different ways you can approach this - I do think ink over silver can give you some nice results. You’ll get a good strong color from the ink, they flow easy, and cover evenly. Regular paint washes and glazes are sometimes trickier to get noce even coats with.
