ANR Halation

Overview

On film, very bright light scatters back into the emulsion and leaves a warm red-orange halo around light sources and hot highlights: halation. This node adds that fringe to digital plates and CG, for a film look or to match footage shot on film.

Highlights above Threshold produce a halo with two parts: a tight one (Tight Radius) and a broad, soft one (Broad Radius), mixed by Broad Balance. Edge Bias keeps the bright core of each light as it is and puts the colour in the fringe around it, which is what sets halation apart from a tinted glow. Colorize moves the halo from the light's own colour toward Halo Color, a warm red-orange by default.

To limit halation to some highlights, connect a matte of them to Area; the halo can still spread past the matte.

Inputs

1. Sourcerequired

   The image to treat, usually the finished comp, in scene-linear colour.

2. Maskoptional

   Limits where the finished effect is blended, by its alpha.

3. Areaoptional

   A matte that chooses which highlights produce halation: white does, black does not. Leave it unconnected to let every highlight produce it.

Output. The Source with the halo added and its alpha unchanged. View can also show the halo alone (Effect) or the highlights that produce it (Emission).

Quick start

1. Add ANR Halation to the finished comp, before grain, and connect it to Source.
2. Set View to Emission and adjust Threshold and Soft Knee until only the brightest lights and highlights are left.
3. Back on Composite, set the strength of the fringe with Halo Intensity.
4. Set its size with Tight Radius and Broad Radius, and how much of the wide, soft part you see with Broad Balance.
5. Adjust Edge Bias: higher keeps the light itself clean and the colour in the fringe. Set the colour with Colorize and Halo Color.

The panel

The node's panel as Nuke shows it, with the values of a new node. Click any control to see what it does; tabs and sections work as in Nuke.

All controls

Tips

• Halation shows most around bright sources against dark areas: practical lights, windows at night, specular glints. Keep it subtle on soft, evenly lit highlights.
• On display-referred images, whose values rarely go above 1, lower Threshold.
• Effect gives the halo alone; grade it and add it back with a plus Merge.
• For a fuller film look, combine it with ANR Diffusion, which softens and blooms the highlights, then finish with ANR Film Grain.

Good to know

• The halo is added as light: around an element with alpha, it has colour but no alpha. A Merge keeps it; a Premult removes it.
• Area reads alpha: a greyscale image with a solid alpha selects the whole frame, so copy the greyscale into alpha first. A connected black or empty matte switches the effect off.
• Runs on the CPU: no GPU and no AI model needed.

Works with

ANR GlowA soft, layered bloom around bright lights and highlights, with control over its size, spread and colour, and a matte input to choose which lights glow.ANR DiffusionSoftens and blooms highlights like a diffusion filter on the lens, while texture and deep blacks stay intact.ANR Film GrainAdds film-like grain that follows the image's brightness, to match CG, paint fixes and clean comps to grainy footage.ANR Lens EffectsGives clean CG or a finished comp the character of a real lens: distortion, colour fringing, soft edges and a vignette, around one centre.