A one-part concentrate (40% potassium carbonate) formulated to develop fully aqueous Riston® photopolymer films. D-4000 is economical to use and easy to handle, eliminating the need to weigh and dissolve powdered materials. It is formulated to give optimum results with DuPont™ Riston® films and FoamFREE™ defoamers in conveyorized spray developer equipment.