 Because the DP70 was intended for use with 70mm film and in large theaters with a long throw to a big screen, several features were included to disperse the intense heat generated by the more powerful lamps with which it was often used.The gate assembly includes copper components which are silver-plated, and a liquid-cooled plate that is fitted with a water pipe surrounding the aperture opening.The use of liquid recirculating equipment and distilled water was encouraged.