There are three: * The penumbra is the part of a shadow where the surface is only partially covered by an object. Parts of the edge of the light source cannot be seen, to differentiate from antumbra. * The umbra is the part of a shadow where the surface is fully covered by an object. * the antumbra is the part where the object is merely a little obstruction from the light source when seen from the surface. The edge of the light source can be seen in full from the surface.