Low-reflectivity aluminum films were prepared using a de magnetron sputtering system under high Ar/O-2 and Ar/N-2 gas pressures. At a wavelength of 436 nm, pure Al films deposited at 4.0 Pa (30 mTorr) in Ar-1.0 vol. % O-2 and Ar-1.0 vol. % N-2 atmospheres show a specular reflectivity of 0.06 and a diffuse reflectivity of 0.10. The low reflectivity is ascribable to the formation of columnar structures of several hundred angstroms with open boundaries. Microvoids formed between columnar crystallites are thought to absorb the incident light. The low-reflectivity Al film coatings will probably make it possible to eliminate the effect of reflection in photolithography.