Photon-induced alterations in the step density of NaCl cleavage faces are observed by electron-microscope surface decoration and compared with corresponding He-atom-scattering data. The experiments carried out at temperatures too low for purely thermal desorption to occur demonstrate that the photon excitation leads to an incomplete layer-by-layer removal which is controlled by repetitive nucleation, spreading, and coalescence of subsequent generations of photon-induced 2D holes. The postirradiation recovery of the specular He intensity is found to be caused by thermal surface smoothing.