Johnathan's absolutely correct about spoon testing. It will save you alot of heartache! The general rule of thumb, is to keep the primer in the body color's spectrum. Reds and oranges use the red oxide color. Dark blues, purples and blacks, use the black primer and of course whites, yellows, sky blues you want a white primer. However, you can easily change the hue or tint of a color by switching up the primers.
If you want your testors bright red really bright shoot it over a white primer. If you want it the shade it's formulated to be, use red oxide. If you want it a shade darker like a blood red, go with the black primer. It's not always that cut and dry and this is why we always suggest the spoon test. Hit the dollar store and pick up a hundred spoons for a buck. You're set for a while!
And yes, silver is a good base for metallics.
Edited by MAGNUM4342, 14 March 2013 - 07:54 PM.