For a picture that is 4 meters high and 10 meters long, if the height of the column is less than 15 meters, the effect can be achieved by using 250W metal halide lamps, using 5 lamps. This saves energy. If the location is good and the ambient light is relatively strong, it is recommended to use 4 400W metal halide lamps. Prices vary from place to place. Generally, Philips light sources are used, and Yamin lamps are sufficient. The price is around 400 yuan per lamp.