GIMP Gradient Shapes: Linear, Bilinear, Radial, Conical

This article explains the functional differences between four primary gradient shapes in GIMP: Linear, Bilinear, Radial, and Conical. While all gradients blend two or more colors smoothly across an area, the shape setting dictates the geometry, direction, and symmetry of that transition relative to your mouse drag. Understanding how each shape handles color distribution will help you choose the right tool for shading, highlights, backdrops, and complex texturing.

Linear Gradient

A Linear gradient transitions colors along a straight path in a single direction. When you click to establish the start point and drag to the end point, the starting color begins at your initial click, transitions smoothly across the length of the vector line, and reaches the ending color at your release point. Beyond the release point, the color remains solid (unless tiling is active). Linear gradients are standard for sky horizons, flat lighting shifts, and basic directional shading.

Bilinear Gradient

A Bilinear gradient is essentially a two-way, mirrored linear gradient. The starting point serves as the center axis of the transition. When you drag outward in one direction, GIMP duplicates the identical gradient transition in the exact opposite direction. This produces a symmetrical highlight or stripe down the center that fades evenly toward both outer edges. It is ideal for rendering cylinder reflections, metallic highlights on pipes, or symmetrical light bands.

Radial Gradient

A Radial gradient renders colors in concentric circles radiating outward from a central anchor. Your starting click determines the center of the circle, while the drag line defines the radius. The starting color dominates the center, gradually transitioning into the outer colors until it hits the defined perimeter of the radius. This shape is best suited for circular light sources, spotlights, round spheres, vignette camera effects, and glowing orbs.

Conical Gradient

A Conical gradient wraps colors around a central point in a sweep, resembling a cone viewed directly from its apex or a spinning radar sweep. Rather than moving outward like a radial gradient, the color values change according to the angle around the center point.

• Conical (Symmetric): Blends the colors outward in both clockwise and counter-clockwise directions from the drag line, meeting seamlessly at the opposite side (180 degrees away) to avoid harsh seams.
• Conical (Asymmetric): Sweeps the full spectrum of the gradient 360 degrees around the center point, creating a hard edge where the 0-degree start meets the 360-degree finish line.

Conical shapes are commonly used to create brushed metal textures, volume knobs, color wheels, and rotational motion blur effects.