 In addition to producing lower levels of light, mismatched bulbs and ballasts will stop working early, or may even burn out immediately.Metal halide bulbs are a type of HID light that emit light in the blue and violet parts of the light spectrum, which is similar to the light that is available outdoors during spring.Because their light mimics the color spectrum of the sun, some growers find that plants look more pleasing under a metal halide than other types of HID lights such as the HPS which distort the color of plants.