Opening a gap in graphene is a challenge to exploit the preferential adsorption of hydrogen in patterns that leave narrow stretches of pure graphene in between. Large-scale superstructures of hydrogenated carbon atoms emerge, turning the sheet into a semiconductor with a bandgap of at least 0.45 eV. Another method used to engineer bandgaps is to cut nanoribbons out of graphene, for instance by plasma etching. The confinement of electrons to nanostructures immediately produces a gap. A graphene-iridium sandwich is exposed to hydrogen, spots where carbon atoms are situated closest to the peaks in the iridium landscape are hydrogenated first. Electrons tend to localize onto these hydrogen-free islands, which leads to a well-defined gap. Chemical vapor deposition makes large-scale production feasible, including the possibility of transferring graphene from one substrate to another.