The Heliopan 55mm 81C Warming Color Conversion Glass Filter reduces blue and green. An 81A can also be used with electronic flash to reduce the amount of "blue" generated by the flash.
Note:
Whereas the 81 Series of filters creates a feeling of warmth, the 82 Series creates a feeling of coolness.
All Heliopan screw-in type and series size filters are mounted in precision black anodized brass rings to eliminate binding or cross threading and to ensure optimal alignment
