> ## Documentation Index
> Fetch the complete documentation index at: https://comfytv.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Histogram Equalize

> Redistribute tones to expand contrast in flat footage — with a strength dial and optional CLAHE-style clipping to tame noise.

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  <img src="https://mintcdn.com/comfytv/dMkMxJDZdIo4YzAU/images/nodes/_placeholder.svg?fit=max&auto=format&n=dMkMxJDZdIo4YzAU&q=85&s=b54171099e5b02d4313fe581171ebbcc" alt="Histogram Equalize" width="800" height="450" data-path="images/nodes/_placeholder.svg" />
</Frame>

## What this node does

**Histogram Equalize** spreads a clip's tonal values more evenly across the range, pulling detail out of flat, low-contrast, or hazy footage. Classic histogram equalization can look harsh, so this node adds a **strength** blend (mix between original and fully equalized) and a **clip\_limit** that caps how much any single tone can be stretched — the idea behind CLAHE — to keep noise and skies from blowing out.

It takes `COMFYTV_VIDEO` in and out and renders on a torch backend (`histeq`), so it has a **▶ Run** with a live preview on the card. With strength at 0 the clip passes through unchanged.

To interoperate with native ComfyUI nodes, add a **Bridge** (see the [Bridge guide](https://github.com/jtydhr88/ComfyTV/blob/main/docs/bridges.md)).

## When to use it

* Rescue flat, low-contrast, or foggy shots
* Bring out shadow/highlight detail before further grading
* Boost local contrast in a controlled way (with clip\_limit)

## Parameters

### strength

How far to push equalization, default 0.5, range 0.0…1.0. It's a blend: 0.0 is the untouched clip (the node becomes a pass-through), 1.0 is full equalization. Start around 0.4–0.6 and back off if it looks harsh.

### clip\_limit

Caps the fraction any single histogram bin can hold, default 0.0, range 0.0…0.1 (step 0.005). `0` means off (plain equalization). Small positive values (this is the CLAHE-style contrast limit) prevent over-amplifying noise in flat regions like skies. Raise it gently if equalization is amplifying grain.

## Outputs

| Output    | Type            | Meaning                              |
| --------- | --------------- | ------------------------------------ |
| **video** | `COMFYTV_VIDEO` | The contrast-equalized clip snapshot |

## Tips

* At strength 0 the node does nothing — turn it up to see any effect.
* If equalizing makes noise or banding worse, add a little `clip_limit` rather than lowering strength all the way.
* This maximizes contrast rather than matching a look — follow it with **Video Color** or a **Video LUT** for the final grade.

## Related nodes

* **Auto White Balance** — the other one-knob automatic corrector (neutral color)
* **Video Color** — manual exposure, levels, and grading
* **Video Curves** — hand-shaped contrast when you want precise control