GIMP Blend Modes: Normal, Dissolve, and Multiply

Layer blend modes in GIMP determine how pixels on an upper layer interact visually with the pixels directly beneath them. While hundreds of creative effects can be achieved using these modes, Normal, Dissolve, and Multiply represent three fundamental, distinct approaches to blending. This article covers the operational mechanics, visual characteristics, and practical use cases for each of these three blend modes.

Normal Blend Mode

Normal is the default blend mode in GIMP.

• How it works: It does not mathematically alter the color values of the underlying layer. Instead, the top layer simply obscures the bottom layer based purely on opacity.
• Opacity behavior: At 100% opacity, the top layer completely covers the bottom layer. Reducing opacity makes the top layer uniformly translucent, smoothly fading into the lower layer across every pixel.
• Best used for: Standard composition, basic layering, and applying standard color adjustments or cutouts without altering the native color math.

Dissolve Blend Mode

Dissolve treats layer transparency differently from any other mode by introducing a dithered, randomized texture.

• How it works: Rather than creating a smooth, semi-transparent fade when opacity is reduced, Dissolve randomly removes individual pixels from the upper layer to reveal the lower layer.
• Opacity behavior: At 100% opacity on a fully solid layer, it looks identical to the Normal mode. However, along soft edges (like feathered brushes) or when layer opacity is lowered below 100%, it produces a speckled, noise-like pattern.
• Best used for: Retro grain effects, vintage print textures, stippling art, and creating rough, sand-like transitions.

Multiply Blend Mode

Multiply is categorized as a darkening blend mode based on mathematical multiplication of color values.

• How it works: GIMP normalizes the color values of both layers between 0.0 (pure black) and 1.0 (pure white), multiplies them together, and outputs the result. Because multiplying fractions yields smaller numbers, the resulting image is always darker than or equal to the original.
• Key characteristics:
  • White is transparent: Any pure white areas on the blend layer become completely invisible.
  • Black remains black: Any pure black areas remain 100% black regardless of what is underneath.
• Best used for: Adding realistic shadows, combining scanned ink drawings with colored backgrounds, applying dark textures, and deepening exposure.

Quick Comparison