Agfa does not recommend to make a correction in development. Agfa recommends to give 1.5 to 2 stops extra if your normal exposure time would be 10 to 100 seconds. Reciprocity law failure is not determined by the shutter speed, but instead by the light intensity the film receives. So what Agfa recommends is not a definite one, depending on your normal rating of the film, etc.(posted 8304 days ago)For long exposure on this film (and TMX), I liked to use dilute Microphen.