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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.

Mask From Image converts an image channel into a single-channel mask. Choose alpha, any individual RGB channel, or luminance as the source.

This is the primary way to create masks from existing image data. Extract the alpha for silhouette masks, or use luminance to create brightness-based selections.

Selection modes

Section titled “Selection modes”

The Mode picker decides what the extracted channel means:

ModeBehavior
Raw (default)Pass the extracted channel through unchanged, as a grayscale mask.
AboveSelect every pixel at or above Threshold.
BelowSelect every pixel below Threshold.
RangeSelect the band between Low and High, with both ends included.

Tonal Softness fades the selection in and out around those values. It is not the same control as Feather: softness follows the pixel’s own brightness, so a gradual tonal transition in the source becomes a gradual mask edge, while Feather blurs the finished mask across the image regardless of what the source looked like.

Threshold used to double as an on/off switch, where 0 meant “no threshold at all”. Mode now carries that decision, so Threshold 0 in Above mode means exactly what it says: select everything from 0 up. Existing projects are converted when opened and produce the same mask they always did.

Parameters

Section titled “Parameters”

Pins

ImageImage
InputRequired
AlphaMask
Output

Mask

ChannelChoice
Default: Alpha

Which 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
  • 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 feather radius applied after threshold

InvertToggle
Default: false

Invert the resulting mask

Usage Tips

Section titled “Usage Tips”
  • Extract from Alpha to get a mask of the image’s transparent areas.
  • Use Luminance to create a brightness-based mask where bright areas become white and dark areas become black.
  • Combine Threshold with Feather for semi-soft selections.
  • Enable Invert to flip the extracted mask without a separate Invert node.
  • Keep Mode on Raw when you want the channel’s full tonal range as a soft mask; switch to Above or Below the moment you want a decision instead of a gradient.
  • Use Range to isolate midtones (say Low 80, High 170), which neither Above nor Below can do on its own.
  • Raise Tonal Softness to keep a thresholded selection from looking cut out, without blurring detail the way Feather does.
Section titled “Related Nodes”