Add Noise to Mask Regions

Most of the masking nodes in this pack exist to clean a mask up - smooth it, threshold it, sharpen it. SaltMaskNoiseAddition does the opposite on purpose. It adds Gaussian noise to a mask's values, and there are real reasons you'd want that.

What it does

The node takes masks and perturbs every pixel value with random noise drawn from a Gaussian distribution, controlled by two optional parameters: mean (default 0, range -255 to 255) shifts the whole mask brighter or darker before the noise is applied, and stddev (default 25, range 0–100) controls how much randomness gets added around that mean - higher stddev means rougher, grainier noise. The single output is the noised MASKS.

Why you'd actually use this

A mask that's too geometrically perfect - a clean CLIPSeg blob, a hand-drawn ellipse - can produce a composite that reads as obviously synthetic, because real edges in photography are never that smooth. A light pass of noise on the mask breaks up that mechanical cleanliness before you use it for a blend or an inpaint boundary, giving the seam a more organic, less "pasted-on" look. It's also handy if you're generating training or test data and deliberately want imperfect masks to augment a dataset rather than a batch of identical, too-clean ones.

Installing it

ComfyUI Manager: search SaltAI-Open-Resources. Or by hand:

cd ComfyUI/custom_nodes
git clone https://github.com/get-salt-AI/SaltAI

Restart ComfyUI. No models, no extra dependencies for this one - it's straightforward numerical noise generation.

Common issues

The main trap is overdoing it. Push stddev too high and your mask stops being a mask and starts being static - you'll lose the actual shape you were trying to preserve, and downstream nodes that expect a coherent region (an inpaint crop, a threshold step) will behave unpredictably on speckled garbage. If you want texture without losing the underlying shape, keep stddev modest and follow this node with SaltMaskSmoothRegion - a light blur after the noise softens the speckle back into something coherent while keeping the edge irregularity you were going for. And remember mean isn't neutral: push it too far off zero and you risk clipping the whole mask toward fully-black or fully-white before the noise even gets a chance to do anything interesting, since mask values only have room to move between 0 and 1 (or 0–255, depending on how your graph represents it) either way.