Inner Glow vs Outer Glow in Adobe After Effects

Inner Glow and Outer Glow are essential Layer Styles in Adobe After Effects used to simulate lighting, depth, and atmospheric radiance on text, shapes, and footage. While both effects generate a gradual color falloff along the boundaries of an alpha channel, Inner Glow casts light inward toward the center of the element, whereas Outer Glow radiates light outward into the surrounding composition. Understanding how to customize their blending modes, spread, and sizing allows motion designers to create everything from subtle bevel-like rim lighting to vibrant neon aesthetics.

What is Inner Glow?

Inner Glow applies a luminous border that emanates from the edge of a layer and fades toward the interior. It affects only the opaque pixels of the selected layer and does not expand outside the layer’s existing boundaries.

  • Primary Purpose: Creates the appearance of internal illumination, rim lighting, or translucent materials like glass, gel, or subsurface scattering.
  • Source Control: Unlike Outer Glow, Inner Glow offers a "Source" setting, allowing the glow to originate either from the Edge (fading inward) or the Center (fading outward toward the edges).
  • Common Use Cases: Simulating backlit buttons, adding depth to flat vector shapes, creating soft bevels, and highlighting the edges of 2D motion graphics.

What is Outer Glow?

Outer Glow projects a radiant aura outward from the silhouette of a layer into the empty or underlying space around it. The glow interacts with whatever visual elements sit beneath the layer in the timeline.

  • Primary Purpose: Simulates light emission, halos, atmosphere, or separation from complex backgrounds.
  • Spread and Size: Outer Glow expands outward based on the "Spread" percentage (which expands the solid core of the glow) and the "Size" value (which controls the blur radius and softness of the light falloff).
  • Common Use Cases: Designing neon signs, creating sci-fi energy fields, crafting celestial halos, and making dark text readable against dark backgrounds without using hard drop shadows.

How to Apply Inner and Outer Glow

Both effects belong to the Layer Styles category, which mirrors standard Adobe Photoshop styling conventions:

  1. Select a layer in your composition timeline.
  2. Navigate to the top menu and select Layer > Layer Styles > Inner Glow or Layer > Layer Styles > Outer Glow.
  3. Expand the layer in the timeline panel, open the Layer Styles drop-down, and customize the glow settings.

Key Parameter Controls

To achieve realistic or stylized lighting, both effects rely on a consistent set of adjustment properties:

  • Blend Mode: Determines how the glow interacts with the layer or background. By default, both use Screen, which brightens underlying pixels. Changing this to Normal allows for solid, opaque halos.
  • Opacity: Regulates the overall transparency of the effect.
  • Color and Gradient: Allows you to choose either a single solid color for the glow or a multi-color gradient for complex light emission.
  • Technique:
    • Softer: Applies a standard Gaussian-style blur for natural, diffused lighting.
    • Precise: Retains the exact contours of the layer's alpha edge, ideal for hard-edged graphic designs.
  • Choke / Spread:
    • Choke (Inner Glow): Tightens the boundary of the inner falloff before blurring.
    • Spread (Outer Glow): Expands the density of the glow before it begins to feather.
  • Size: Defines the overall distance the glow travels in pixels.
  • Range: Adjusts the distribution curve of the glow, controlling whether the falloff concentrates near the source edge or extends further out.