Hmc hoya multi coated these are light balancing filters used to decrease the colour temperature slightly for a warmer redder tone this product is designed to correct tendencies toward bluish tones and controls the coloration that affects daylight film the hoya hmc 81a filter removes any unwarranted blue from the effects of electronic flash for example 81a should be selected when using tungsten type b colour film 3200degk with photoflood lamps 3400degk these filters can be