Adjust Gamma

Adjust Gamma is the mid-tone brightness knob in Mira's little image-adjustment set. Gamma is the correction that lifts or crushes the middle of the tonal range without moving pure black or pure white much - it's how you brighten the shadows of a too-dark render, or add weight to a washed-out one, without simply sliding the whole exposure. If your generation's tonal balance is off in the middle, this is the targeted fix.

It's a Util/Image node in ComfyUI_Mira, mirabarukaso's utility pack, and it sits alongside the pack's other simple adjustments - contrast, brightness, saturation, hue, sharpness, tone curve, grayscale, RGB channel. They're all built to daisy-chain, so gamma is one link in a short color-correction line you build right in the graph rather than exporting to an editor.

How it works

The node applies a gamma curve to the input image, scaled by a single level value that runs from 0 to 10 with a fine step (0.001). Gamma is a power-curve remap: it bends the mid-tones up or down while leaving the extremes comparatively fixed, which is exactly why it's the right tool for "the midrange is too dark/light" as opposed to a flat brightness shift.

One honest caveat: the node defaults level to 0, and the exact neutral point isn't obvious from the outside, so don't assume a particular number means "no change." The practical approach is to nudge the value and watch the preview - gamma is a look-at-it adjustment anyway.

Inputs and outputs that matter

• src_image - the image to adjust.
• level - the gamma control, 0 to 10. Because the neutral point isn't self-evident, treat this as a dial to preview against rather than a precise value to type once.

The output is image, the adjusted result - a plain IMAGE, so it chains straight into the next adjustment node.

Installing it

ComfyUI Manager: search ComfyUI_Mira in the Custom Nodes Manager, Install, restart. Manual: cd ComfyUI/custom_nodes && git clone https://github.com/mirabarukaso/ComfyUI_Mira.git, then restart ComfyUI. If the pack errors on load, run pip install -r requirements.txt in its folder and restart. No models required.

Common issues

The main friction is exactly that unobvious neutral point - set level blind and you may get a bigger shift than you wanted. Preview as you go, and make small moves. Gamma pushed hard will flatten or blow out the midrange, which looks like a "muddy" or "plasticky" result; back it off if that happens.

Order matters when you chain it with the pack's other adjustments - gamma before contrast lands differently than contrast before gamma, because each is reshaping the histogram the next one reads. And keep gamma corrections modest if the image is headed into an upscale or further editing; heavy tonal remaps early can cost you detail you'd rather keep. For a quick "lift the shadows a touch" on a finished render, though, it's the right, small tool.