Inner Glow

A bright glow that radiates INWARD from the shape's edges — the "inside" complement to Glow.

Category: Effects Menu path: Effects > Inner Glow

Ports

Port	Type	Direction	Description
in	imageRgba16f	input	Input image
out	imageRgba16f	output	Image with the inner glow composited inside it

Parameters

Param	Type	Default	Description
color	color	white (1,1,1,1)	Glow color in linear space.
offset	vec2	(0, 0)	Optional directional displacement in pixels (X, Y). Default (0,0) glows evenly from all edges inward. Keyframeable.
blur	scalar	20	Gaussian blur radius for the glow softness. Keyframeable.
intensity	scalar	1	Glow strength. 0 = invisible, higher = brighter. Keyframeable.
spread	scalar	0	Controls glow alpha hardening. 0 = soft natural falloff, 1 = hard edge before blur. Keyframeable.
blendMode	enum	Add	How the glow brightens the input: Add (additive) or Screen.
output	enum	Composite	Composite brightens the input in place. Glow Only outputs just the colored glow (transparent elsewhere). Matte outputs a grayscale intensity mask.

Expose Channels

When enabled (E button on node header), adds input ports that override params via edge connections:

Port	Type	Overrides
intensity_in	scalar	intensity

How It Works

The inner glow is a three-pass operation that mirrors Inner Shadow but adds light instead of darkness:

1. Extract pass: The shape's alpha is sampled at the offset position and inverted (1 - alpha). Near the edges the inverse is high (strong glow source); deep in the interior it is 0. The result is hardened by spread, scaled by intensity, and tinted with the glow color.
2. Blur pass: The inner source is gaussian-blurred for soft falloff.
3. Composite pass: The blurred source is clipped to the inside of the shape (blurred.a × input.a) and brightens the input via the chosen blend mode (Add or Screen). The output alpha equals the input alpha, so the silhouette is unchanged.

Because the effect is clipped to the input alpha it never extends beyond existing content bounds, so it does not expand the layer's bounds.

Usage Examples

Basic: Neon edge

1. Add an Inner Glow node after a shape or text outline
2. Set color to a bright cyan, blur to 15, intensity to 1.5
3. The inner rim of the shape lights up like neon

Creative: Soft inner highlight

1. Keep offset (0, 0) so the glow comes from all edges
2. Set color to warm white, blur to 30, intensity to 0.8, blendMode to Screen
3. Adds a gentle interior sheen without blowing out the center

Advanced: Directional inner rim light

1. Set offset to (-8, -8) to bias the glow toward one edge
2. Use a colored glow plus Add blend mode for a rim-light look
3. Animate intensity (or drive intensity_in) for a pulsing glow

Tips

• Default offset (0, 0) is the classic "inner glow" look; non-zero offset biases the light directionally
• Add clips highlights brightly; Screen is softer and stays within range
• Glow Only lets you composite the glow downstream with a custom blend via Merge
• Set output to Matte to drive a Grain/Colorize mask concentrated along the inner edges
• Intensity is unbounded — values above 1 push into HDR for strong bloom in linear space

Related Nodes

• Glow — the "outside" bloom complement
• InnerShadow — same pipeline but darkens instead of brightens
• DropShadow — outward offset shadow
• Merge — composite the Glow Only output with custom blending