LUMA
Node Reference

Color Nodes

Nodes for generating and transforming color signals -- constant colors, gradients, chroma palettes, and spectral shifting.

Color Nodes

Color nodes generate and transform color signals.


Color

FieldValue
Type IDcolor
CategoryColor
DescriptionConstant color generator.

Inputs

None.

Outputs

PortType
outSignal (N=1, T=1, C=4 RGBA)

Parameters

NameTypeDefaultDescription
colorJSON string--Color as {"r": 0-255, "g": 0-255, "b": 0-255, "a": 0-1}

Behavior

  • RGB values in the parameter are 0-255 integers; they are normalized to 0.0-1.0 in the output signal.
  • Alpha is already 0.0-1.0 in the parameter.

Gradient

FieldValue
Type IDgradient
CategoryColor
DescriptionMaps a scalar input signal to a color range via linear interpolation.

Inputs

PortTypeRequired
inSignal (C >= 1)Yes
start_colorSignalNo (overrides start_color parameter)
end_colorSignalNo (overrides end_color parameter)

Outputs

PortType
outSignal (N=in.N, T=in.T, C=4 RGBA)

Parameters

NameTypeDefaultDescription
start_colorhex string"#000000"Color at input value 0.0
end_colorhex string"#ffffff"Color at input value 1.0

Behavior

  • The input signal's first channel (C=0) is used as the interpolation factor.
  • Input values are expected in the 0.0-1.0 range; values outside this range will extrapolate.
  • Wired start_color and end_color inputs override the corresponding parameters.
  • Interpolation is performed independently per RGBA channel.

Chroma Palette

FieldValue
Type IDchroma_palette
CategoryColor
DescriptionMaps 12-pitch chroma distribution to RGB color via weighted palette lookup.

Inputs

PortTypeRequired
chromaSignal (C=12)Yes

Outputs

PortType
outSignal (N=1, T=chroma.T, C=3 RGB)

Parameters

None.

Pitch-to-Color Palette

PitchColor
CRed
C#OrangeRed
DOrange
D#Gold
EYellow
FGreenYellow
F#Green
GCyan
G#DeepSkyBlue
ABlue
A#BlueViolet
BMagenta

Behavior

  • Output color is the weighted sum of all 12 palette entries, where weights come from the chroma distribution.
  • Auto-gain normalization ensures consistent brightness regardless of chroma magnitude.

Spectral Shift

FieldValue
Type IDspectral_shift
CategoryColor
DescriptionRotates input color's hue based on the dominant pitch in a chroma signal.

Inputs

PortTypeRequired
inSignal (C >= 3, RGB)Yes
chromaSignal (C=12)Yes

Outputs

PortType
outSignal (N=1, T=min(in.T, chroma.T), C=3 RGB)

Parameters

None.

Behavior

  • Converts input color to HSL, shifts hue by (dominant_pitch / 12) * 360 degrees, converts back to RGB.
  • The dominant pitch is the channel index with the highest value in the chroma distribution at each time step.
  • Creates harmonically-responsive color shifting that tracks chord changes.

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