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Levels

Node icon
Color

Adjusts the tonal range with input/output levels and gamma, per-channel or master.

The Levels node applied to a source image — original (left) and result (right).
Side-by-side comparison: the original image on the left and the same image after the Levels node on the right.

Levels is a fundamental tonal adjustment. The input range clips shadows (Input Black) and highlights (Input White), compressing the tonal range. Gamma adjusts midtones: values below 1.0 darken, above 1.0 brighten. The output range then remaps the result to a new brightness window.

Clamp Output (on by default) limits the result to the Output Black to Output White range. Turn it off to let values continue past the endpoints, which preserves brighter-than-white detail through the adjustment in a 32-bit document. Dragging Output White above 1.0 turns it off for you.

Each channel (Red, Green, Blue, Alpha) can be adjusted independently, or use Master to adjust all at once. The histogram at the top of the panel shows every color channel’s distribution together and updates live as you drag the sliders. On a single-channel image, the adjustment applies to that one channel and the output stays single-channel.

Parameters

Section titled “Parameters”

Pins

ImagePixels
InputRequired
MaskMask
InputOptional
ImagePixels
Output

Color

ChannelChoice
Default: Master

Which channel to adjust (Master affects R/G/B equally)

  • MasterAdjust all RGB channels together, affecting overall brightness and contrast.
  • RedAdjust only the red channel, affecting red/cyan color balance.
  • GreenAdjust only the green channel, affecting green/magenta color balance.
  • BlueAdjust only the blue channel, affecting blue/yellow color balance.
  • AlphaAdjust the alpha (transparency) channel, affecting opacity levels.
Master In BlackNumber
Default: 0.000 Range: 0.000–1.000

Master input shadow clipping point. Pixels at or below this become Output Black

Master In WhiteNumber
Default: 1.000 Range: 0.000–1.000

Master input highlight clipping point. Pixels at or above this become Output White

Master GammaNumber
Default: 1.00 Range: 0.01–9.99

Master midtone gamma

Master Out BlackNumber
Default: 0.000 Range: 0.000–1.000

Master output shadow level. The darkest value after adjustment

Master Out WhiteNumber
Default: 1.000 Range: 0.000–1.000

Master output highlight level. The brightest value after adjustment

Red In BlackNumber
Default: 0.000 Range: 0.000–1.000

Red input shadow clipping point. Pixels at or below this become Output Black

Red In WhiteNumber
Default: 1.000 Range: 0.000–1.000

Red input highlight clipping point. Pixels at or above this become Output White

Red GammaNumber
Default: 1.00 Range: 0.01–9.99

Red midtone gamma

Red Out BlackNumber
Default: 0.000 Range: 0.000–1.000

Red output shadow level. The darkest value after adjustment

Red Out WhiteNumber
Default: 1.000 Range: 0.000–1.000

Red output highlight level. The brightest value after adjustment

Green In BlackNumber
Default: 0.000 Range: 0.000–1.000

Green input shadow clipping point. Pixels at or below this become Output Black

Green In WhiteNumber
Default: 1.000 Range: 0.000–1.000

Green input highlight clipping point. Pixels at or above this become Output White

Green GammaNumber
Default: 1.00 Range: 0.01–9.99

Green midtone gamma

Green Out BlackNumber
Default: 0.000 Range: 0.000–1.000

Green output shadow level. The darkest value after adjustment

Green Out WhiteNumber
Default: 1.000 Range: 0.000–1.000

Green output highlight level. The brightest value after adjustment

Blue In BlackNumber
Default: 0.000 Range: 0.000–1.000

Blue input shadow clipping point. Pixels at or below this become Output Black

Blue In WhiteNumber
Default: 1.000 Range: 0.000–1.000

Blue input highlight clipping point. Pixels at or above this become Output White

Blue GammaNumber
Default: 1.00 Range: 0.01–9.99

Blue midtone gamma

Blue Out BlackNumber
Default: 0.000 Range: 0.000–1.000

Blue output shadow level. The darkest value after adjustment

Blue Out WhiteNumber
Default: 1.000 Range: 0.000–1.000

Blue output highlight level. The brightest value after adjustment

Alpha In BlackNumber
Default: 0.000 Range: 0.000–1.000

Alpha black-point input

Alpha In WhiteNumber
Default: 1.000 Range: 0.000–1.000

Alpha white-point input

Alpha GammaNumber
Default: 1.00 Range: 0.01–9.99

Alpha midtone gamma

Alpha Out BlackNumber
Default: 0.000 Range: 0.000–1.000

Alpha output black

Alpha Out WhiteNumber
Default: 1.000 Range: 0.000–1.000

Alpha output white

Clamp OutputToggle
Default: true

Limit the result to the Output Black to Output White range.

Turn it off to let values continue past the endpoints, preserving brighter-than-white detail through the adjustment.

Dragging Output White above 1.0 turns this off automatically.

Display

Show HistogramToggle
Default: true

Render the histogram overlay above the sliders

Mask

Mask FromChoice
Default: Luminance
Color image connected to the mask input

How the connected color image is read as a mask

  • LuminanceRead the image's brightness as the mask. The default.
  • AlphaRead the image's transparency as the mask.
  • RedUse the red channel as the mask.
  • GreenUse the green channel as the mask.
  • BlueUse the blue channel as the mask.
Mask FitChoice
Default: None (native size)
Mask connected

How the mask is sized when it doesn't match the image

  • None (native size)Center the mask at its native size, with no resizing. Unmasked regions are unaffected.
  • StretchStretch the mask to exactly match the image dimensions. May distort the mask shape.
  • Fit (letterbox)Scale the mask to fit inside the image, preserving aspect ratio. Letterboxes where needed.
  • Fill (crop)Scale the mask to fill the image, preserving aspect ratio. Crops edges if aspect ratios differ.

Usage Tips

Section titled “Usage Tips”
  • Drag Input Black right to clip dark noise; drag Input White left to boost dim highlights.
  • Use Output Black > 0 to lift the shadows (no pure black) for a faded/matte look.
  • Adjust individual channels to correct color casts. For example, reduce Input White on Blue to warm up an image.
  • Connect a mask input to apply the tonal adjustment to only part of the image.
Section titled “Related Nodes”