The Heliopan 28mm KR-15 (85B) Filter is a color conversion filter that helps to slightly decrease color temperatures and provide a warming effect. The 85B converts daylight (approximately 5500K) to 3200K in order to use tungsten-balanced film outdoors.
There is a 1.5x filter factor with this filter, requiring an increase of 0.6 stop for normal exposure. It has a 28mm brass mounting ring that is painted a matte black to help reduce reflections. The SH-PMC multi-coated Schott glass provides greater contrast and reduced reflection compared to uncoated filters.
