In my experience, black candy is not going to give you much color. if you do it the way candy usually is done, i.e. candy over a silver or gold metallic base, you just get a dark gray metallic'y candy. The more coats you do, the darker it gets, but you lose the metallic base.
For a color change black, I use an interference pearl the color I want, over a straight black base. In shadow it is black, when the sun hits it at certain angles, it glows the the color. Some dark candies look almost black, and glow in the sun , but the color difference is not a great. I've done red over a black pearl base to get this effect. But the color in the shade doesn't always look true black.
But you have to use the right kind of pearl. In the day, we used to call it flip flop pearl. House of Kolor has lots of color choices. You need very little over black to get it looking good, too. You need more pearl over lighter colors. Do test panels before you paint it on your vehicle.