The Rosco CalColor #4290 Blue Filter (3 Stop, 48"x25' Roll) is designed specifically to the spectral sensitivity of color film. This filter color is designed in 90 density corresponding to the familiar 3 stop calibration. In color photography, the light-sensitive emulsion layer separately record the individual blue component of the spectrum.
CalColor filter adjusts the transmission of the color component at the individual light source in a familiar and reliable manner. As a result, the cinematographer can exercise selective and predictable control over the image's coloration as rendered by the film.