MX_Glow

MX_Glow is the cheapest way in the MX pack to make something look like it's emitting light. It takes your image, blurs it, and adds the blurred copy back on top at an intensity you control. That's the entire trick - and it's the same trick behind most "bloom" and neon-glow looks you see in game engines and poster edits.

It's part of Intersection98/ComfyUI-MX-post-processing-nodes, and it's a great post-VAE-decode addition when a render's bright areas come out flat. A subtle glow sells emissive signage, sun, and window light; a strong one turns any image into synthwave album art.

How it works

Two steps, both on the tensor. First it builds a Gaussian kernel (derived from blur_radius) and convolves the whole image, exactly like the pack's MX_Blur node. Then it computes:

image + blurred_image * intensity

So the effect is additive: the blurred bright areas get laid over the original, which makes highlights spread outward into a halo while shadows stay roughly put. The blur spreads the light, and intensity decides how much of that spread halo actually shows. Note this is an additive glow, not a screen-blend glow - it will push highlights toward white rather than just tinting them.

The inputs that matter

• image - your IMAGE tensor.
• blur_radius - 1 to 50, default 5. How far the light spreads. Small radii give a tight neon edge; larger radii give a soft, dreamy bloom. For a "backlit" look on a subject, this is the dial that controls how much atmosphere surrounds them.
• intensity - 0 to 5, default 1. How much of the blurred copy is added back. 0.2–0.5 is a whisper of bloom; 1+ is pronounced glow; 3+ starts clipping highlights to pure white.

Output is a single IMAGE, same resolution.

Install

Standard MX pack install. ComfyUI Manager (search MX or ComfyUI-MX-post-processing-nodes), or:

cd ComfyUI/custom_nodes
git clone https://github.com/Intersection98/ComfyUI_MX_post_processing-nodes
cd ComfyUI_MX_post_processing-nodes
pip install -r requirements.txt

Restart ComfyUI; it's under postprocessing/Effects. No models, no downloads.

Where people get burned

The main trap is overshoot. Because the glow is additive and unclamped until the very end, pushing intensity or blur_radius high washes the whole frame toward white - there's no built-in mask, so everything glows, not just the bright pixels. If your whole image looks milky, you've got intensity too high. Second, since the blur is a fixed full-frame Gaussian, the glow halo is uniform and can look synthetic on very detailed textures. Two practical fixes: keep blur_radius modest relative to image resolution, and if you want a glow that only wraps the bright speculars, you'd normally want the pack's MX_Blend in screen mode with a low blend_factor instead - the additive version here is the blunt, effective one. For the classic "neon sign at night" grade, blur_radius ~8, intensity ~0.8 is a solid starting point.