ANR Diffusion

Overview

Diffusion imitates a mist or diffusion filter in front of the lens: bright areas bloom softly into their surroundings and fine bright detail softens, while the rest of the image keeps its texture and contrast. Use it to take the hard digital edge off highlights, or to match a plate shot through such a filter.

Highlights above Threshold spread over Diffusion Radius. Bloom sets how much light they scatter, and Highlight Softness softens the bright detail itself. Detail Protection limits that softening so texture survives, and Black Protection stops the scattered light from lifting the shadows, so blacks stay deep.

To diffuse only some highlights, connect a matte of them to Area. For a bigger, more visible bloom use ANR Glow; for the coloured film fringe, ANR Halation.

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 diffuse: white does, black does not. The scattered light can spread beyond it. Leave it unconnected to let every highlight diffuse.

Output. The Source with diffused highlights and its alpha unchanged. View can also show only the change (Effect) or the selected highlights (Emission).

Quick start

1. Add ANR Diffusion 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 highlights you want to bloom are left.
3. Back on Composite, set how far the light spreads with Diffusion Radius and how much with Bloom.
4. Raise Highlight Softness to soften the bright detail; lower Detail Protection to let it go further.
5. If the shadows look milky, raise Black Protection.

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

• For subtle finishing, start with a small Bloom and keep Detail Protection and Black Protection high.
• With Detail Protection at its default 0.75, Highlight Softness is gentle; lower Detail Protection when the highlights should look truly soft.
• Lower Threshold to diffuse more of the image, like a heavier filter; raise it to affect only the brightest lights.
• Combine it with ANR Halation and finish with ANR Film Grain for a film look.

Good to know

• 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.
• The scattered light is added as light: around an element with alpha, it has colour but no alpha, so a Premult removes it.
• 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 HalationAdds the warm red-orange fringe that film shows around bright lights and hot highlights.ANR Film GrainAdds film-like grain that follows the image's brightness, to match CG, paint fixes and clean comps to grainy footage.