Films are closely conformed to substrates by reducing the air pressure to a subatmospheric level in at least one airflow pathway that is present in the film or the substrate. The reduced air pressure enables the film to tightly contact the substrate in locations where protrusions or depressions on the substrate are present. The method is particularly useful for conforming film containing graphics to a variety of substrates such as the sides of semi-trailers or concrete block walls, even in instances where the semi-trailer sides include rivets and/or grooves and where the concrete block wall is relatively rough.