Image Noise Using Mask

Image Noise Using Mask does exactly what the name says: it drops random noise into the parts of an image your mask covers, and leaves everything else untouched. That might sound like a party trick, but it's a genuinely useful preprocessing move - it's how you force a regeneration in a specific region, add texture where a previous pass came back too smooth, or break up artifacts before an img2img pass without re-noising the whole frame.

How it works

You feed in image, mask, and a few controls, and get back a single noised image. The core knobs:

• strength (0–1, default 0.5) - how strongly the noise is applied in the masked region. 0 means no visible change; 1 means the masked area is essentially replaced by noise.
• noise_scale (0.25–128, default 1) - the size/coarseness of the noise. Below 1 you get fine static; crank it up and the noise becomes chunky blotches, which can read as film grain or texture depending on the effect you're after.
• monochrome - switch noise from full color to grayscale, which is the right call when you want texture without adding rainbow speckle (skin, fabrics, film grain).
• seed - controls the noise pattern, so you can keep the exact speckle from run to run or vary it.

Since it's an image transform, the output wires into the same places an img2img image would go - the key use is feeding the noised image into a sampler as a starting point where the masked region gets regenerated while the unmasked region survives.

Why it's useful

The realistic use case is prep for img2img: rather than denoising the whole frame (which drifts everything), you noise only the region you want to change and feed the result to a sampler at a moderate denoise. The masked area starts from mush and regenerates; the rest of the image holds. It's the same idea as the noise injection inside some inpainting setups, but as a standalone node you can put anywhere in the graph, with a mask you drew or generated.

Installing it

It's part of supElement/ComfyUI_Element_easy:

cd ComfyUI/custom_nodes
git clone https://github.com/supElement/ComfyUI_Element_easy.git

Restart ComfyUI, or install via ComfyUI Manager by searching ComfyUI_Element_easy.

Gotchas

The main trap is feathering - if your mask has hard edges, the noise will have hard edges too, and the boundary between noised and clean pixels will be visible in the result. Blur or feather the mask first, or grow it a few pixels so the transition lands somewhere harmless. Also remember monochrome exists: full-color noise on a monochrome target or on skin reads as garbage color speckle, and people who skip the toggle are the ones who decide the node "adds artifacts." It doesn't - it adds exactly what you asked for.