paste - consistency photopolymer is imaged onto printed wiring boards by coating the board overall and positioning the photographic film over the board in register and off - contact . a resilient blade is pressed against the phototool at one end of the board and drawn across the surface , thus forcing the photographic film into intimate contact with the photopolymer and purging all air therebetween . mounted on the resilient blade aft of leading edge is a shuttered tubular lamp which hardens the photopolymer where the photographic film is clear , so that in a single pass the photographic film is sequentially mated and photopolymer exposed , to produce line widths unmatched by competing dry film systems and at speeds of 0 . 5 feet per second .