Inner Glow for Vector Graphics in Adobe Photoshop

This article explores how Adobe Photoshop’s Inner Glow layer style accentuates internal edges in vector graphics, creating visual depth and defined perimeters without altering the underlying vector paths. By manipulating color falloff, blending modes, and edge distribution, designers can transform flat vector shapes into dimensional, illuminated, or recessed elements.

The Mechanism of Inner Glow on Vectors

Inner Glow operates directly along the boundary path of a vector shape layer. Unlike raster artwork, vector paths provide Photoshop with mathematically precise edges. When an Inner Glow is applied, the rendering engine casts light, tint, or shade inward from these exact borders toward the interior of the shape. Because it functions as a non-destructive layer style, any adjustments to the vector's anchor points, strokes, or curves automatically recalibrate the glow effect in real time.

Defining Edge Contrast with the "Source" Setting

The core control for edge accentuation is the Source parameter, which offers two modes:

• Edge: Emits the effect directly inward from the perimeter vector path. This concentrates the highest density of color along the border, naturally drawing the viewer's eye to the transition between the shape and its background.
• Center: Radiates the glow outward from the geometric center toward the boundaries. This is less about accentuating borders and more about creating a soft, ambient core. For crisp boundary definition, the "Edge" setting is standard.

Tightening Perimeters Using Choke and Size

To control how sharply the interior boundary is defined, Photoshop provides the Size and Choke sliders:

• Size controls the distance the glow travels into the shape from the edge. Smaller values keep the accentuation focused strictly on the contour line, creating a crisp rim-light or highlighted border.
• Choke determines the density and transition gradient of the glow. Increasing the Choke value compresses the falloff, pushing the opaque color closer to the outer boundary. At high Choke settings, Inner Glow mimics an inset stroke or hard bevel rather than a soft radiance, providing extreme edge definition.

Simulating Depth and Bevels with Blending Modes

While named "Inner Glow," the feature is not restricted to bright light. Its functionality depends heavily on the selected Blend Mode:

• Highlighting (Screen, Lighten, Color Dodge): Paired with bright colors, these modes simulate a backlit surface, edge translucency, or specular edge highlights, making the vector look elevated and polished.
• Shadowing (Multiply, Linear Burn): Paired with dark colors, the glow acts as an inner shadow that traces the entire vector perimeter uniformly (unlike the standard directional Inner Shadow). This produces ambient occlusion, making the shape appear cut out or set deeply into the canvas.

Dynamic Vector Scalability

Because Inner Glow is applied to a vector shape layer, the boundary accentuation scales cleanly. Adjusting the shape via the Direct Selection tool or resizing the layer updates the boundary glow immediately without creating pixelation or edge artifacts, preserving the crisp finish essential to modern icon, UI, and logo design.