Brightness

Brightness is the simplest kind of image adjustment node: one image in, one number, one image out. No curves, no per-channel controls, no masking - just a single factor that pushes the whole image lighter or darker. If you've used PIL's ImageEnhance.Brightness directly, this is that, wearing a node's clothes: factor of 1.0 leaves the image untouched, values below 1.0 darken it (0.0 goes to black), and values above 1.0 brighten it, scaling linearly the further you push past 1.

It's not trying to replace a real color-grading stack - there's no gamma control, no highlight/shadow split, nothing selective. What it's good for is exactly the quick, blunt adjustment its simplicity implies: nudging an image slightly darker before a ControlNet preprocessor that's sensitive to exposure, correcting a batch that came out a touch too dark or bright, or building a quick A/B comparison by generating the same image at a couple of brightness factors.

The inputs and outputs that matter

• image - the IMAGE to adjust. Required.
• factor - default 1 (unchanged). Lower it toward 0 to darken, raise it above 1 to brighten. There's no built-in clamp, so extreme values just push the image toward pure black or heavily blown-out, same as you'd expect from a linear scale with no ceiling.
• Output - IMAGE, adjusted.

How to install it

Ships with the full LogicUtils pack. Via ComfyUI Manager: search ComfyUI-LogicUtils, install, restart. Or manually:

cd ComfyUI/custom_nodes
git clone https://github.com/aria1th/ComfyUI-LogicUtils

then restart ComfyUI. No models to download - this runs on the same PIL install ComfyUI already ships with, so there's nothing extra to fetch.

Background on the pack: it's written by aria1th, publicly known as AngelBottomless, the trainer behind Illustrious XL - the SDXL anime finetune that displaced Pony Diffusion v6 as the open-source default. LogicUtils is his side project, and the README says exactly where the docs stand: "Proper documentation is being prepared, however there are too many nodes." That's held since the repo's last push in early 2026. It's a real, used pack - it turns up as a dependency in complex published workflows next to rgthree-comfy and comfyui-kjnodes - it's just documented by its defaults rather than an actual writeup, which is what this article is filling in.

Common issues & troubleshooting

Image blew out to solid white (or went to solid black). factor has no upper clamp, so a value pushed too high (or a 0 for black) will do exactly what you told it to. Bring it closer to 1 and step in smaller increments - differences under 1.2 or so are usually plenty for a subtle correction.

Adjustment looks too uniform / flattens contrast you wanted to keep. That's inherent to a single linear factor - it scales the whole image the same way regardless of what's already bright or dark in it. For anything selective (protecting highlights, only darkening shadows), you'll need a proper curves or levels node from a different pack; this one is intentionally a blunt instrument.

Wanted to adjust saturation, not lightness. That's this pack's Color node, not Brightness - same shape (image plus a single factor), different axis.