Ilford ID11 Developer for black & white film (1960457) It comes in powder form to make 1 liter.It is used where fine grain negatives are required without a loss of emulsion speed. Features: Development time in tanks (68°F/20°C) for Ilford Delta 100 35mm film: Stock solution = 7 min. Diluted 1+1 = 10 min. Diluted 1+3 = 15.5 min. For Ilford Delta 400 35mm film (at 400 exposure): Stock solution = 7 min. Diluted 1+1 = 10.5 min. Diluted 1+3 = 18 min. One liter of working strength stock solution (not diluted) will process 10 rolls of 35mm/120 film. Diluted 1+1 it will process up to 5 rolls of 35/120 film. Storage time for Unopened full bottle ID-11 Stock solution is 6 months . For half full bottles of stock solution storage time is 1 month. If stock is diluted it can only be used as a "one-shot" developer and should not be stored.