  We model the optical visibility of monolayer and bilayer graphene deposited
on a silicon/silicon oxide substrate or thermally annealed on the surface of
silicon carbide. We consider reflection and transmission setups, and find that
visibility is strongest in reflection reaching the optimum conditions when the
bare substrate transmits light resonantly. In the optical range of frequencies
a bilayer is approximately twice as visible as a monolayer thereby making the
two types of graphene distinguishable from each other.
