Your 5 basic color systemThat wouldn't have anything to do with old english heraldy.Example:You have red black and blue as your base colors, and white and yellow are your "metallic colors"You can mix a color from group one and one from group two in order to contrast , but if you use two colors from the same group.i.e. Red and yellow look fine together, as do black and white, but don't mix red and black together, as they won't contrast well enough