Chroma Key Node

The Chroma Key node determines if a pixel is a foreground or background (and thereby should be transparent) based on its chroma values.

Use this, for example, to composite images that have been shot in front of a green or blue screen.

Inputs

Image

Standard color input.

Key Color

The background color usually selected using the color picker and the original image.

Properties

Acceptance

An angle on the color wheel that represents how tolerant the keying color is. Larger angles allow for larger variation in the keying color to be considered background pixels.

Cutoff

Controls the level that is considered the pure background. Higher cutoff levels mean more pixels will be 100% transparent if they are within the angle tolerance.

Falloff

Increase to make nearby pixels partially transparent producing a smoother blend along the edges.

Outputs

Image

Image with its alpha channel adjusted for the keyed selection.

Matte

A black-and-white alpha mask of the key.