These are color conversion filters for the use of tungsten type color films in daylight. 85 decreases the color temperature from 5500?K to 3400?K for the use of Type A color films. 85B decreases the color temperature from 5500?K to 3200?K for the use of Type B color films. 85C decreases the color temperature from 5500?K to 3800?K. The effect obtained is the same as with daylight type color films used in daylight. HMC-These popular filters are renowned for their ability to minimise reflection at the filter surfaces which reduces flare and ghosting. The result is an average light transmission of over 97%, giving sharp contrast and well balanced color. HOYA HMC filters are recommended for enhancing the performance of today's multicoated lenses.