Additive (Linear Dodge) blend mode sums pixel values, producing glowing brightness that clips to white on overflow

Linear Dodge (Add): f(a,b) = a+b, clamped to [0,1]. Since values can only increase, this always produces the same or lighter colours. Values above 1.0 clip to white. This is also called ‘plus lighter.’ The additive mode is fundamental for glow, fire, particle, and lens flare effects: compositing a dark background with a bright glow element adds light without touching dark areas. In live visual coding (Hydra, Processing) additive blending is widely used for feedback loops and particle trails.

Examples

In Hydra: .add(other, 1) computes additive blend. Fire on black background: Screen or Add both work; Add is simpler. Particle systems on dark backgrounds: each particle adds light to the scene.

Assessment

Predict what happens when you additive-blend a red glow (r=0.8,g=0,b=0) over a dark blue (r=0,g=0,b=0.6). Compute the result. What happens if you blend two bright sources that each have r=0.7?