FERandomizedColor2Image

The docstring says "generate a random RGB color." The code does not do that. FERandomizedColor2Image actually fills an image with standard-normal random noise - every channel of every pixel drawn from a normal distribution, seeded and reproducible. So the honest name would be something like "seeded noise image generator," and once you know that, it's a handy little test tool that's been hiding in the fexli/test menu.

Why would you want an image of pure noise? A few genuinely practical reasons:

• Debugging. It's the fastest way to generate a fully deterministic, seed-controlled random image to feed into a VAE encode, a sampler, or a node you're testing - no checkpoint loading, no prompt, no waiting.
• A random background or canvas. Composite it under your content and you've got a seeded "this side is random" region.
• Reference for img2img experiments. Feed it through a low-denoise pass to see what the sampler does with pure randomness.

Inputs and output

• seed - pins the noise field. Same seed, same image, always.
• height / width - dimensions, default 512, 0–8192 in steps of 8.
• batch_size - how many noise images, 1–64, default 1.

Output: image, a float tensor in 0–1... well, almost. The one thing to know: the code uses torch.randn, which is normal-distributed - values cluster around 0 and routinely dip negative or exceed 1. The node doesn't clamp or normalize, so you can end up with a dark, slightly-out-of-range image rather than a bright uniform gray. If you're feeding it into something that assumes 0–1, expect it to look dim. That's arguably a bug, arguably a feature (it's "real" noise), but it's the behavior you'll get.

A quick note on the sibling

If you actually wanted a solid random color image - a flat fill of one seeded color rather than noise - the pack has FEColor2Image for converting a color to an image, and FERandomizedColorOut for generating the random color itself. This node is the noise one. Don't mix them up and then wonder why your "solid color" is speckled.

Install

It's in fexli-util-node-comfyui:

cd ComfyUI/custom_nodes
git clone https://github.com/fexli/fexli-util-node-comfyui
cd fexli-util-node-comfyui
pip install -r requirements.txt

Or ComfyUI Manager → search fexli-util-node-comfyui → install → restart. No dependencies beyond the pack's usual light two, no config.yaml needed.

Verdict: it's a test node, unapologetically, and it's marked fexli/test for a reason. But seeded, reproducible noise is one of those things you'll suddenly need at 2am while debugging, and it does it in one click.