A system for spray coating a substrate with a liquid coating material incorporating a coater provided with a chamber in which spray nozzles (26a,26b) are provided to spray the liquid coating material on to a substrate (l0) which is moved through the chamber by appropriate means. Overspray control means are provided to convey airborne overspray from the coating chamber wherein particles of film-forming material in the overspray are collected. Air flow control means are provided to draw ambient air through the chamber at such a rate that airborne overspray is transported to the particle collector without drawing substantial spray material from the chamber.