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Mask From Image

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Mask

Extracts a grayscale mask from any channel of an image: alpha, red, green, blue, or luminance.

A brass gramophone rendered on transparency, the checkerboard showing round it, beside the mask Mask From Image takes from its alpha: the gramophone white, the surround black

Pick Channel Alpha (the default) for a silhouette, or Luminance for a brightness-based selection.

Selection modes

Section titled “Selection modes”

Mode decides what the extracted channel means.

  • Raw passes the channel’s full tonal range through as a soft mask.
  • Above, Below, and Range turn it into a decision at Threshold or between Low and High. Range isolates a band such as the midtones (say Low 80, High 170), which neither Above nor Below can do on its own.

Tonal Softness fades the selection in and out around those values. Unlike Feather, which blurs the finished mask spatially, it follows each pixel’s own value, so a gradual transition in the source becomes a gradual mask edge. Raise it to keep a thresholded selection from looking cut out without blurring detail.

Parameters

Section titled “Parameters”

Pins

ImageImage
InputRequired
AlphaMask
Output

Mask

ChannelChoice
Default: Alpha

Source channel to extract as the mask

  • AlphaUse the transparency channel: bright where opaque, dark where transparent.
  • RedUse the red channel as the mask source.
  • GreenUse the green channel as the mask source.
  • BlueUse the blue channel as the mask source.
  • LuminanceUse perceived brightness, the most natural representation of "light vs dark."
ModeChoice
Default: Raw Range: Raw / Above / Below / Range

How the extracted values become a selection:

  • Raw: pass the extracted channel through unchanged.
  • Above: select pixels at or above Threshold.
  • Below: select pixels below Threshold.
  • Range: select pixels between Low and High (both endpoints included).
ThresholdInteger
Default: 128 Range: 0–255
Above and Below modes

Pixels at or above this value are selected (Above), or below it (Below)

LowInteger
Default: 64 Range: 0–255
Range mode

Lower end of the selected band. Included in the selection

HighInteger
Default: 192 Range: 0–255
Range mode

Upper end of the selected band. Included in the selection

Tonal SoftnessInteger
Default: 0 Range: 0–255
Above, Below and Range modes

Softens the selection around the value boundaries.

Feather blurs the mask spatially instead.

Feather (px)Number
Default: 0.0 Range: 0.0–100.0

Gaussian blur radius to soften mask edges. Set to 0 for hard-edged masks

InvertToggle
Default: false

Invert the mask: white becomes black and vice versa

Section titled “Related Nodes”