you dont have to back it with white, if you are going to back with white use 2light coats otherwise you will get that milky white look, you can also either mix them with other colors which is a little easier but takes some more plug and play or you can again do the light coat and back with any other color. if you go too heavy they will make any color look milky and shitty. they a little tricky to use but can add a whole level of dimension to your work

slim how in the F!@# did u do that in 5 hours???