The Tiffen 138mm 85B Color Conversion Filter helps to decrease the color temperature from 5500 to 3200K, allowing the use of tungsten-balanced film in daylight conditions. The warming effect of this filter requires a 0.6-stop increase in exposure for normal results.
This filter is made using ColorCore technology, a process that involves laminating the filter substrate between 2 pieces of optical glass, grinding flat to a tolerance of 1/10,000th of an inch, and then mounting to precision metal rings.
Color conversion filter decreases color temperature and provides a warming effect.
Converts 5500 to 3200K for using tungsten-balanced film in daylight conditions.
Filter factor of 1.6 requires a 0.6-stop increase in exposure.