ILFORD ILFOSTOP is a low odour citric acid stop bath. After development we recommend that films and papers are rinsed in an acid stop bath to stop development immediately and neutralise the developer to help maintain the activity of the fixer bath. It is specifically recommended for dish/tray processing of paper or deep tank processing of film. ILFOSTOP helps to maintain the activity and prolong the life of the fixer solution by reducing carry over of excess developer (alkaline) into the fixer bath (acidic).