Glow

Filter

Adds a bloom/glow effect around every pixel whose brightest channel clears a threshold.

Click to zoom

The Glow node applied to a source image: original (left) and result (right).

Glow extracts the pixels above the Threshold, blurs them, and blends them back over the image, giving the soft bloom around highlights familiar from film and game rendering.

Threshold is compared against each pixel’s brightest channel, so a saturated red, green, or blue glows as readily as white of the same strength. At 0 everything glows, at 1 nothing does.

Glowing over transparency

Three options, all on by default, decide how the glow behaves on artwork with transparent areas, such as a stroked shape or a line of text on an empty background:

• Glow Over Transparency lets the light spill onto transparent pixels, so the glow composites over anything downstream as light. Fully transparent pixels also stop feeding the glow, so color hidden under a transparent area never brightens its visible neighbors.
• Preserve Brightness keeps the glow as bright beside the shape as the shape itself, however thin the stroke, however large the Radius, and however narrowly its color clears the Threshold. Turn it off for a physical bloom that dims as it spreads.
• Expand Canvas grows the output on whichever edges the glow would overflow. It needs Glow Over Transparency and the Add or Screen blend (Soft Light adds no light to empty areas), and a fully opaque image, such as a photo, never changes size. Turn it off when the output must stay aligned pixel for pixel with the input.

Documents saved before these options existed

Documents saved before these options existed open with Preserve Brightness and Expand Canvas off, so their glow strength and canvas size stay put. Their Glow nodes also keep comparing Threshold against perceived brightness, where pure red and blue read much darker than white, so saturated colors glow as they did. A new Glow node reads the brightest channel.

In a 32-bit document

In a 32-bit (Float) document, a brightest channel above the Threshold selects a pixel for the glow rather than multiplying it. The glow carries the highlight’s own brightness, so one Intensity setting looks the same whether the image is graded into the 0 to 1 range or holds values far above it.

Threshold is compared against linear light

In linear light a mid-bright color sits lower than it looks: a light gray can fall under the default Threshold of 0.4 and not glow at all, so lower Threshold until it does.

With the Add blend, light above white is carried downstream and into a float export, while an 8-bit document clips it at white.

Parameters

Pins

↳ImageImage

InputRequired

↳MaskMask

InputOptional

↦ImageImage

Output

Filter

ThresholdNumber

Default: 0.40 Range: 0.00–1.00

Only pixels whose brightest channel exceeds this contribute to the glow. 0 = all pixels glow, 1 = nothing glows.

RadiusNumber · px/%

Default: 10.0 Range: 1.0–300.0 px / 0–100%

Glow spread radius. Larger values produce a wider, softer glow

IntensityNumber

Default: 1.00 Range: 0.00–5.00

Glow brightness multiplier. 0 = no glow, higher = brighter.

Color

TintColor (RGB)

Default: rgb(255, 255, 255)

Glow tint color

Blend

Blend ModeChoice

Default: Add

How glow is composited onto the original

• AddAdds the glow directly, which can clip to white in very bright areas.
• ScreenScreen blend that brightens without clipping. Most natural-looking glow.
• Soft LightSubtle, gentle glow that enhances brightness without a strong bloom effect.

QualityChoice

Default: Medium (3 passes)

Number of blur passes for smoother glow. More passes = smoother but slower

• Fast (1 pass)One blur pass. Fastest, but may show slight banding in the glow.
• Medium (3 passes)Three blur passes, giving a smooth glow with good performance.
• High (6 passes)Six blur passes, giving the smoothest possible glow, best for final output.

Options

Preserve BrightnessToggle

Default: true

Keep the glow as bright as the pixels it comes from, however thin the shape or large the Radius. Intensity scales from there.

Turn this off for a physical bloom, which dims as it spreads.

Glow Over TransparencyToggle

Default: true

Let the glow spill onto transparent areas, so a shape on an empty background glows outward.

Turn this off to keep the input's transparency exactly as it is. Soft Light never lights empty areas.

Expand CanvasToggle

Default: true

Glow Over Transparency on, Add or Screen blend

Auto-expand the output canvas so the glow is not clipped at the edges.

Turn this off to keep the original canvas size.

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

• Use a colored Tint for stylized effects: warm for golden hour, cool for sci-fi.
• Connect a mask to restrict which pixels are glow sources. The bloom still spreads naturally beyond the masked area.

Related Nodes

• Blur
• Levels
• Vignette