Thin films of Cu(In,Ga)Se2 were formed from precursor films of (In,Ga)2Se3. The films are smooth, with large, tightly packed grains. Photovoltaic devices made from these films show great tolerance in the efficiency to variations in film composition, and scalability of the process appears promising. A device made from one of these films resulted in the highest total‐area efficiency measured for any non‐single‐crystal, thin‐film solar cell, at 15.9%.