With double the strength of the KR 3, the KR 6 filter leads to neutral color rendition in strong haze, or in mountains above 2500 m (8200 feet) when transparencies are not to show “blue mountains” (which can also be attractive, depending on the individual case). It should not be used for photographs of typically foggy landscapes. Another field of application would be interior photographs on daylight reversal film when only blue light from the sky and no direct sunlight is coming through the window, and no fill-in flash is being used. In combination with tungsten reversal film, the KR 6 filter imparts the warmth of normal incandescent bulbs to the light emitted by halogen bulbs, which would appear neutral white without a filter. Its filter factor is approximately 1.4.