Glow

Renders always have one thing missing: the way bright light bleeds into the pixels around it. Glow is the two-minute version of that - blur the image, add the blur back on top, done. It's the difference between a streetlamp that's just a bright spot and a streetlamp that emits light. For anime, neon signs, magic effects, or anything with a light source, this is the node you'll reach for.

How it works

The mechanism is gloriously simple, and it's exactly what you'd write yourself: the image gets a Gaussian blur with a kernel sized to 2 * blur_radius + 1, then the blurred copy is added back to the original multiplied by intensity, and the result is clamped to 0–1. Because only the bright, blurred areas survive the addition, you get a bloom around highlights instead of an overall haze. It's a "screen-glow" bloom, not a physically-plausible one - but at these speeds you won't care.

• intensity (0–5, default 1) - how strongly the bloom adds back. Above ~2 the highlights start to wash toward white; the clamp will hold it at 1 but you'll be riding the edge of blowing out.
• blur_radius (1–50, default 5) - the spread of the glow. Small radii give a tight, crisp halo around edges; big radii turn the whole bright area into a soft light cloud.

Output is a single IMAGE. Wire your render in, get the glowing version out.

Install

Glow is part of ComfyUI-post-processing-nodes, so one install gets you all ~22 of the pack's effects.

• ComfyUI Manager: search "post processing nodes", install, restart.
• Manual:

cd ComfyUI/custom_nodes
git clone https://github.com/EllangoK/ComfyUI-post-processing-nodes

Restart after. There's no requirements.txt, no models to fetch, no pip - it runs on torch's conv2d with a hand-built Gaussian kernel, which stock ComfyUI already has. It lives under postprocessing → Effects in the node menu.

What to expect

The honest critique: this is a blunt instrument compared to the pack's fancier nodes. There's no threshold to pick which highlights glow and no tone-mapping, so on a busy image it can soften everything a touch. The fix is to keep blur_radius small (3–8) and intensity around 0.5–1.5, and if you want selective bloom, run it through a mask first. But for a quick pass that makes lights read as lights, it does exactly what it says, with no surprises.