I've done bead blasting, which is just a finer grain of sand. For a desird finish, you're right in that it will be reflected in the preparation work involved. A sloppy polishing job means that the blue won't be as pleasing. With regards to nickeling, that entails a copper undercoat followed by immersion into a nickeling compound. The color of nickel will be "white" and how it appears depends on the prep work. If the metal surface is highly polished, the nickel will appear like a mirror (the classic nickel finish). However, if the metal surface was bead blasted first, the nickel will appear frosted. I suppose if the metal was sandblasted for an even rougher metal surface, the nickel would look like stainless with a dull white.