Can FAS Be Used Together with Optical Brightening Agents (OBAs)?

“FAS and optical brightening agents can be used in the same overall process, but they are normally applied in separate stages. The extent of interaction depends on OBA chemistry, formulation additives and process conditions. Recommended sequence: FAS reductive bleaching, washing, then OBA application under the supplier's recommended conditions. Residual chemical levels should be confirmed before OBA addition.”