Purpose
- The filter absorbs some ultraviolet (UV) light and counteracts the excessive blue coloration that can be caused by haze, especially in aerial or marine environments.
Color
- As a C.K.3 filter, it has a yellowish tint to neutralize the blue cast and warm the overall color balance of the film. Early documentation for Cine-Kodak color filters notes that the CK-3 is a compensating filter that requires increasing the camera aperture by one stop to compensate for the light absorbed.
Compatibility
- The "U7" or "Series 7" designation refers to its size and mounting style, indicating it was designed for a specific set of Kodak lenses. The U7/Series 7 filters were unthreaded, requiring a special adapter ring or lens mount to hold them in place.
Application
- The filter was used with daylight-balanced film, such as Kodachrome, to correct for color balance in hazy or bright sunlight condition
.jpg)
