Non Red Key effect

The Non Red Key effect creates transparency from green or blue backgrounds. This key is similar to the Blue Screen Key effect, but it also lets you blend two clips. In addition, the Non Red Key effect helps reduce fringing around the edges of nontransparent objects. Use the Non Red Key effect to key out green screens when you need to control blending, or when the Blue Screen Key effect doesn’t produce satisfactory results.

The following Non Red Key effect settings are adjusted in the Effect Controls panel:

Threshold: Sets the levels of blue or green that determine transparent areas in the clip. Dragging the Threshold slider to the left increases the amount of transparency. Use the Mask Only option to view the black (transparent) areas as you move the Threshold slider.
Cutoff: Sets the opacity of nontransparent areas specified by the Threshold slider. Higher values increase transparency. Drag to the right until the opaque area reaches a satisfactory level.
Defringing: Removes residual green or blue screen color from the edges of the opaque areas of a clip. Choose None to disable defringing. Choose Green or Blue to remove a residual edge from green‑screen or blue‑screen footage, respectively.
Smoothing: Specifies the amount of anti‑aliasing (softening) that Adobe Premiere Pro applies 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.