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Chroma Key

Node icon
Keyer

Removes a green/blue screen background with spill suppression and matte refinement.

A green-screen plate keyed and despilled in one pass: the background removed and green spill fully suppressed.
A before/after: a portrait shot against a green-screen backdrop, and the final image with the background keyed out and green spill fully suppressed, leaving clean hair edges on transparency.

Chroma Key turns every pixel close to the key color transparent.

  • Similarity sets how far from the key color still counts as background.
  • Blend softens the transition at the subject’s edges.

Besides the keyed image, the node outputs the Matte on its own for further refinement.

Screen light bouncing onto hair and skin leaves a colored fringe after keying. Raise Spill Suppression to remove it, or set Despill Algorithm to Robust for the cleaner neutralization the standalone Despill node uses.

Parameters

Section titled “Parameters”

Pins

ImageImage
InputRequired
ImageImage
Output
MatteMask
Output

Keyer

KeyColor (RGBA)
Default: rgba(0, 255, 0, 255)

Key color

SimilarityNumber
Default: 0.25 Range: 0.00–1.00

How far from the key color is still considered background. Higher = more aggressive keying

BlendNumber
Default: 0.15 Range: 0.00–1.00

Transition zone width between keyed and kept pixels. Creates smoother edges around the subject

Despill

Spill SuppressionNumber
Default: 0.00 Range: 0.00–1.00

Reduce color bleed from the key color onto the subject. Desaturates pixels near the key color

Despill AlgorithmChoice
Default: Simple Range: Simple / Robust
  • Simple: limits spill the way Chroma Key always has.
  • Robust: uses the shared Despill algorithm for cleaner channel-neutralization.
Despill BalanceNumber
Default: 0.50 Range: 0.00–1.00
Despill Algorithm = Robust

Which of the two non-key channels the spill is limited toward. 0.5 (center) uses their average. For a green key, 0 favors Red and 1 favors Blue. (Robust despill only.)

Despill ModeChoice
Default: Neutralize Range: Neutralize / Desaturate
Despill Algorithm = Robust
  • Neutralize: reduce the key channel toward the other channels.
  • Desaturate: blend key-dominant pixels toward luminance.

(Robust despill only.)

Mask

Clip BlackNumber
Default: 0.00 Range: 0.00–1.00

Matte values below this threshold clip to fully transparent. Cleans up near-transparent areas

Clip WhiteNumber
Default: 1.00 Range: 0.00–1.00

Matte values above this threshold clip to fully opaque. Cleans up near-opaque areas

Invert MatteToggle
Default: false

Invert the generated matte: keeps the key color and removes everything else

Usage Tips

Section titled “Usage Tips”
  • Use the eyedropper beside the key color to pick the exact screen color from the image.
  • Start with a low Similarity and raise it until the background is cleanly removed.
  • Raise Clip Black and lower Clip White to crush the matte’s shadows and highlights for a cleaner key.
Section titled “Related Nodes”