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

# Light Graffiti

> Paints with light — bright pixels leave glowing trails across the clip, in one ▶ Run.

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

## What this node does

**Light Graffiti** accumulates the brightest parts of a `COMFYTV_VIDEO` over time, so moving light sources (sparklers, phone screens, headlights) smear into persistent glowing streaks, like a long-exposure light-painting photograph. It writes a new snapshot on **▶ Run**.

In and out are both `COMFYTV_VIDEO`. To feed native ComfyUI nodes, insert a **Bridge** — see the [bridge guide](https://github.com/jtydhr88/ComfyTV/blob/main/docs/bridges.md).

## When to use it

* Turn a sparkler, flashlight, or LED wand into drawn strokes of light.
* Build up neon-trail visuals from moving highlights in a night shot.
* Emulate a long-exposure light-painting effect from ordinary video.

## Parameters

### threshold

Per-channel brightness above which a pixel counts as "light," `0.5`–`1.0` (step `0.005`), default `0.9`. Lower catches dimmer highlights; higher keeps only the brightest points.

### sum\_threshold

Combined R+G+B brightness gate, `0.0`–`3.0` (step `0.05`), default `2.2`. A second, total-brightness test so only genuinely bright (not just one hot channel) pixels paint.

### decay

How fast the accumulated trail fades over time, `0.0`–`1.0` (step `0.005`), default `0.0`. At `0` trails persist for the whole clip; raise it to make streaks fade behind the moving light.

### gain

Brightness boost applied to the accumulated trails, `0.1`–`4.0` (step `0.05`), default `1.0`. Higher makes the light-painting glow more intense.

## Outputs

| Output    | Type            | Meaning                                          |
| --------- | --------------- | ------------------------------------------------ |
| **video** | `COMFYTV_VIDEO` | The light-painted clip as a new project snapshot |

## Tips

* If nothing is trailing, lower **threshold** and/or **sum\_threshold** so more pixels qualify as light.
* Keep **decay** at `0` for permanent strokes; add a little to let older trails dim behind the source.

## Related nodes

* **Feedback FX** — recursive echo/vertigo trails driven by feedback mixing.
* **Strobe** — punctuate the light with interval flashes.