Hydrogenated semiconductor films have been studied for their application as possible optical recording media. We characterize three different recording processes, which are based on hydrogen evolution in amorphous (a) hydrogenated semiconductor materials without melting. Bulges (or bubbles) of ≤μm diameter are created in a-Si:H. The written marks in a-Ge:H resemble a circular sponge-like microswelling. At higher intensity, ablation without melting is occurring in a-Si:H, where holes with sharp edges are produced. These recording materials could be used for low cost archival disks, which would be also adaptable to replication.