The latest in his 4-part series of “phenomenological” environments, Kurt Hentschläger’s SUB (2019) opens at iMAL, Brussels, for its European premiere. Set in complete darkness and augmented by ambient surround sound, an LED wall erupts with animated 1/3 sec bursts of intensely bright light, “tingling your senses by skippering between depriving and overloading them.” Available photos capture those bursts, as the intense retinal after-images viewers experience—the actual artwork—can’t be documented.