Gaussian Blur

JDC_GaussianBlur is the least glamorous node in comfy-plasma, and it's also the one you'll reach for more often than you expect. It blurs an image with a Gaussian kernel. That's it. No modes, no masks, no radius presets pretending to be features - one image in, one image out, with a single radius slider. It's the sort of node you'd assume ComfyUI already has, and then discover you're glad this pack ships one.

How it works

It's a thin wrapper around Pillow's ImageFilter.GaussianBlur. The blur_radius float (default 1, range 1–1024) controls the standard deviation of the kernel - bigger radius, softer result. The math is the classic weighted average: each pixel becomes a blend of its neighbors, weighted by a Gaussian falloff, which gives you a soft, natural-looking blur without the "smear" of a simple box blur.

Two honest caveats from the schema: the minimum radius is 1, so you can't set it to 0 for a "no-op" pass (not that you'd want to), and the upper bound of 1024 is more than enough to turn any sane image into fog. At high radii on a big image it's CPU work, but Pillow's GaussianBlur is well-optimized - you're not going to feel it unless you're pushing 4K.

Input: IMAGE. Output: IMAGE.

When you'd reach for it

• Smoothing noise before it feeds a sampler. Blur a JDC_Plasma or JDC_RandNoise output and you get soft, organic texture instead of harsh static - a genuinely useful trick for structured img2img starts.
• Softening a blend. Run one side of JDC_BlendImages through a blur first and the crossfade loses its hard edge.
• Preparing for inpainting. A gentle blur on the masked region's edge can hide seams.
• Background separation. A heavy blur on a depth/region-isolated background gives you fake depth-of-field in two nodes.

It's not an upscaler's blur - you wouldn't use this for quality work, and it won't protect edges the way a bilateral filter would. But for "make this softer," it's exactly right.

Install

No requirements.txt, no models. ComfyUI Manager → Install Custom Nodes → search comfy-plasma → install, restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/Jordach/comfy-plasma

Restart ComfyUI. It's under image/postprocessing.

Common issues

The only real "issue" is scale: people start at the default radius of 1, see almost no change, and slam the slider to 20 expecting drama - then wonder why everything is mush. At default 512×512, radius 2–3 is a visible softening, 5–8 is dreamy, past 15 it's fog. Start low and creep up; Gaussian blur reaches "too much" surprisingly fast. And as with the rest of the pack, it's single-image, so no batching.