Glow

Glow [Glo] is the native 2D Fusion blur-and-brighten node, distinct from Resolve FX Light Glow on Edit/Color pages and from Soft Glow. It blurs the input, amplifies the generated pass and composites the result with the original image.

The node has THREE inputs: orange Input for 2D pixels, blue Effect Mask applied after processing to restrict final contribution, and white Glow Mask that pre-masks the source before halo generation, allowing light to grow beyond the mask edge.

Filter offers eight methods. Box is quick, Bartlett softer, Multi-box exposes a pass count for smoother approximation, Gaussian and Fast Gaussian are conventional soft filters; Blend, Hilight and Solarize are different looks, not simply higher quality.

The open original screenshot glow-filter.png confirms all eight filter names; glow-controls.png captures Fast Gaussian selected. Num Passes is therefore absent in the screenshot, because this control appears only when Multi-box is selected.

R/G/B/A toggles above Lock X/Y select components before filtering. Color Scale modifies the generated halo afterward. Filter=Blend, the Blend slider, and Apply Mode represent entirely separate stages and must never be merged into one tutorial control.

Lock X/Y links glow size on both axes; unlocked settings allow different spread horizontally and vertically. Glow Size governs the footprint while Glow governs added intensity. Very high gain can flatten the source into white highlights.

Clipping Mode is about domain of definition, not RGB highlight clipping. Frame expands processing to the full frame, Domain honors the upstream domain, while None disables source-image clipping. Test sparse transparent artwork near image boundaries.

Apply Mode Normal composites glow over the source, Merge Under places the halo behind source alpha, and Threshold exposes a conditional High-Low range. Threshold is NOT a permanently visible generic slider in the standard Glow Controls.

Color Scale includes a Pick button and independent Red/Green/Blue/Alpha multipliers, not the imaginary standalone Glow Color field described in the legacy page. These multipliers should be tuned on the halo, not treated as a full-frame color grade.

For neon text, keep a sharp Text+ core on its own branch. Add a Glow to a second branch and return both through Merge, preserving visibility and control over alpha and layering.

Judge glow at 100%, on both light and dark backgrounds, in Viewer RGB and Alpha, and over time. Wide filters can expand work domains and slow high-resolution comps even when the still frame looks good.

The content targets Fusion 21 based on the reference manual and two preserved Inspector screenshots. Typed diagrams are editorial proof of valid data types, not native Resolve socket-ID, render, alpha math or performance certification.