🐧 Adjust Brightness Contrast Gamma

Every second workflow ends with a "slightly too dark, slightly flat" output, and the standard response is three separate nodes - or editing the PNG in another app. This node does the three-in-one: brightness, contrast, and gamma adjustments in a single step, with all three defaulting to neutral so it's a no-op until you touch it. It's the simplest member of the 🐧 SuperNodes color family, and it exists because "the image is fine except it isn't" is a per-render problem you fix in the graph, not in an editor.

How it works

Three floats in, one IMAGE out:

• brightness - 0 to 4, 1.0 neutral. Multiplicative, so 1.5 is noticeably brighter, 0.8 darker. The default range is generous enough to rescue a genuinely dark pass.
• contrast - 0 to 4, 1.0 neutral. Below 1 flattens, above 1 punches. 0 is a flat gray-out, which is why you might not want to park it there.
• gamma - 0.05 to 4, 1.0 neutral. This is the one people confuse with brightness: gamma shifts the mid-tones without crushing blacks or blowing whites. A small gamma tweak (0.9–1.1) is the single most common "make it look less washed out" fix.

The adjustment runs through a proper sRGB-to-linear conversion, applies the operations in linear light, and converts back. That matters more than it sounds: operating on the gamma-encoded values directly (as many quick implementations do) shifts colors and makes brightness changes look different than the numbers suggest. Doing it in linear light keeps skin tones from drifting when you touch contrast.

When you'd reach for it

• Final grade between the VAE decode and Save Image.
• Consistent output across a batch: same three values applied to every frame/image for a uniform look.
• Quick correction before a color-match or white-balance step downstream.

Install

ComfyUI Manager, search "ComfyUI-SuperNodes", or:

cd ComfyUI/custom_nodes
git clone https://github.com/sonnybox/ComfyUI-SuperNodes

Restart ComfyUI. No model downloads. The pack's only extra dependency is matplotlib, and it's only for the Sigmas Graph node - this node adds nothing. The pack targets ComfyUI's newer extension API, so keep ComfyUI updated.

Gotchas

• All three are multiplicative around 1.0, not additive. If you're coming from image editors where "brightness +10" means +10 units, translate your instincts: think "×1.2," not "+20."
• There's no preview inside the node (it's a plain image-out node), so hook the output to a preview and iterate. The values are cheap to test - a single re-run per tweak.
• If you need saturation, hue, or white balance in the same breath, the pack's Adjust Color AIO bundles these three with those - this node is the deliberately narrow version.

It's boring on purpose. One image in, one image out, three well-behaved sliders, linear-light math so nothing surprising happens to your colors. That's the right amount of ambition for a color-correction node.