Blue Screen Key effect (Windows only)

The Blue Screen Key effect creates transparency from true chroma blue. Use this key to key out well‑lit blue screens when creating composites.

The following Blue Screen Key effect settings are adjusted in the Effect Controls panel:

Threshold: Sets the levels of blue that determines transparent areas in a clip. Dragging the slider to the left increases the amount of transparency. Use the Mask Only option to view black (transparent) areas as you drag the Threshold slider.
Cutoff: Sets the opacity of nontransparent areas specified by the Threshold setting. Dragging the Cutoff slider to the right increases the opacity. Use the Mask Only option to view white (opaque) areas as you drag the Cutoff slider.
Smoothing: Specifies the amount of anti-aliasing (softening) applied to the boundary between transparent and opaque regions. Choose None to produce sharp edges, with no anti-aliasing. This option is useful when you want to preserve sharp lines, such as those in titles. Choose Low or High to produce different amounts of smoothing.
Mask Only: Displays only the clip’s alpha channel. Black represents transparent areas, white represents opaque areas, and gray represents partially transparent areas.

Subject is photographed against blue background (left). Blue Screen Key effect is applied (right) to superimpose subject over underlying track.

For more information about using blue screen and green screen effects, see the the video tutorial, Behind The Scenes In Metacafe News, on the Metacafe website.