First Surface refers to applying a decal directly to the glass surface. The art is on the front side of the print. When standing outside, you view the print directly. You can also choose to use a spot white under base on your first-surface decal. This is a layer of white ink printed behind the art to make your design more vibrant while keeping the background transparent. A decal without the under base isn’t as bright and can be slightly washed out from sunlight.