This acts as a base and gives eyeshadow intensity. It really makes the colors pop!
There are two different types: one with a matte base and the other with a frosted base. The matte base will give a more powdered finish, and the frosted base will give a metallic effect. Sometimes you need to apply two layers to get a good base, or you can put a little powder of a similar color over a cream base to set it. Apply primer all over the eyelid and usually up to the eyebrow in a stroking motion.