ILFORD ILFOSTOP is a low odour, citric acid stop bath which stops further development of paper or film. It also prolongs the life of the fixer bath, maintaining the activity of your fixer solution, by neutralising the developer.
We recommend that all black & white films and darkroom papers are rinsed in ILFOSTOP after development, especially when dish/tray processing paper or deep tank processing film.
ILFOSTOP is available in 500ml bottles of concentrate, this makes 10 litres of working strength solution enough to process 150 135 36 or 120 films or 600 20.3×25.4cm (8×10 inch) RC prints or 300 20.3×25.4cm (8×10 inch) FB prints.
ILFOSTOP contains an indicator dye that is pH sensitive and changes colour from yellow to purple as the stop bath becomes exhausted. 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). It is not recommended for machine processing applications as the short fix and wash times often used may leave a residual dye stain on films and prints. The longer wash times usually associated with dish/tray and tank processing minimise this risk.
Do not let developer become contaminated with a stop bath solution.