Use the controls on the Film tab to reduce the effects of cyan undercutting. These controls are only available when Film box is checked on Ultimatte tab. You can view the results better when you select subject in the overlay dropdown menu on the Ultimatte tab.
Due to the nature of film’s emulsion layers, a phenomenon know as cyan undercutting exists that reveals itself as a smeared red edge in areas of sharp transitions, which can best be seen by viewing the individual RGB channels of a film image. Normally, this phenomenon is not a problem until bluescreen compositing techniques are applied. Since the red emulsion layer tracks at a slower rate than the blue and green emulsion layers, the artificial red edge it produces are retained as foreground detail resulting in an unacceptable composite.
• transparency - Use this control to adjust the amount of Film Correction in partially transparent foreground objects (such as hair detail).
• correction - Use this control to adjust the amount of correction in the individual RGB channels of the foreground image.
• strength - Use this control to adjust the overall amount of Film Correction that is applied to the foreground image.
• shrink - Use this control to shrink the subject overlay.
• brights - Use this control to include or eliminate bright areas from the subject overlay.
• darks - Use this control to include or eliminate dark areas from the subject overlay.