Sharpness

Sharpness does exactly what the name says: you hand it an image and a number, and it hands back a sharper (or softer) version. No model, no VAE, no fancy edge-detection kernel you have to configure - one image in, one float, one image out. It's part of ComfyUI-LogicUtils, a grab-bag of small logic/math/data utility nodes from aria1th, who's better known under the AngelBottomless handle as the person who trained the Illustrious XL checkpoints. The README's entire documentation effort is one sentence - "proper documentation is being prepared, however there are too many nodes" - so treat this page as the docs that never got written.

How it works

The signature is a dead giveaway even without seeing the source: an image in, a factor that defaults to 1, and an image back out. That's the exact shape of Pillow's ImageEnhance.Sharpness - 1.0 leaves the image untouched, push it toward 2 or 3 to sharpen, dial it down toward 0 and you get a soft, slightly blurred image instead. I can't see the implementation, but that default-of-1-means-neutral pattern is a strong tell, and it's the standard way this kind of single-knob enhancer works in Python image tooling generally.

Inputs and outputs

• image - the picture to adjust. Comes straight off a VAE decode, another image node, or a loaded file.
• factor - the one control. 1 = no change, above 1 sharpens, below 1 softens.

Output is a single IMAGE, ready to chain into a preview, a save node, or another image op.

Where you'd actually use it

The realistic case is a cheap post-process pass: you've upscaled or run img2img and the result looks a hair soft, and you want a bit more edge definition without spinning up a whole upscale model just for that. Drop this after your decode, nudge factor up a bit, and look at the result before deciding whether it's worth keeping - oversharpening reads as ugly haloing around edges fast, so small moves (1.2, 1.5) go a lot further than you'd expect.

Installing it

ComfyUI Manager → Install Custom Nodes → search ComfyUI-LogicUtils → install → restart. Or by hand:

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

No model files, and by community report, no real dependencies to fight either - a thread on r/StableDiffusion recommending lightweight logic-node packs over heavier, less-maintained ones (WAS Node Suite, Impact Pack) for a simple comparison task pointed straight at LogicUtils specifically because "it doesn't have dependencies." That tracks with the README: its own auto-install hook is opt-in (COMFYUI_LOGICUTILS_AUTO_INSTALL=1) and can be force-disabled (COMFYUI_LOGICUTILS_SKIP_INSTALL=1), which only makes sense if there's basically nothing that needs installing by default.

Common issues

There isn't much surface area for bugs here - it's one float and one image. The thing worth knowing: this pack hasn't been touched since 2026-01-21 by the author's own commit history. That's not "broken," it's just dormant - aria1th moved on to a wildcards pack right after this one, then off image generation entirely. If a future ComfyUI core change ever breaks the image tensor handling here, don't expect a fast upstream fix; it's the same trade-off you'd be making with any small, single-maintainer utility pack.

If you loaded a shared workflow and ComfyUI flags SharpnessNode as missing, that just means the sender had this pack installed and you don't - install it the same way above, or via Manager's "Install Missing Custom Nodes."