Methods for monitoring and detecting optical emissions while performing photoresist stripping and removal of residues from a substrate or a film stack on a substrate are provided herein. In one embodiment, a method is provided that includes positioning a substrate comprising a photoresist layer into a processing chamber; processing the photoresist layer using a multiple step plasma process; and monitoring the plasma for a hydrogen optical emission during the multiple step plasma process; wherein the multiple step plasma process includes removing a bulk of the photoresist layer using a bulk removal step; and switching to an overetch step in response to the monitored hydrogen optical emission.