REINER RIEDLER: SWEAT For his latest project, Reiner Riedler works with a completely new “camera-less” technology. His negatives are made of cotton cloth that is treated with sensor dyes. The material is thus reactive: when in contact with sweat, a chromatic process is set in motion and the background changes color from pink to yellow. The fabric is placed either on top or underneath the sweaty bodies for a few minutes and there is only one attem…