To explore water pollution, Eva Falk-Drake used Direct Positive Photographic Paper loaded into a 5x4 camera. The direct positive prints were made on the waterways around Cardiff and then coloured with acrylic paint. The colour base of the photographs correlates with the pH of the water sampled, which is an indicator of the pollution level.
“Extremes in pH can make a river inhospitable to life and low pH is especially harmful to immature fish and insects. Acidic water also speeds the leaching of heavy metals harmful to fish.”