---
title: LTX-2.3 Relight (Video Relighting IC-LoRA)
emoji: 💡
colorFrom: blue
colorTo: yellow
sdk: gradio
sdk_version: 5.49.1
app_file: app.py
pinned: false
short_description: Relight exterior video clips with a light-direction ball
python_version: "3.10"
startup_duration_timeout: 3h
models:
  - Lightricks/LTX-2.3
  - Lightricks/LTX-2.3-22b-IC-LoRA-Relight
---

# LTX-2.3 Relight — Video Relighting with a Light-Direction Ball

Relight any exterior video clip by choosing a **light direction** (azimuth /
elevation / hardness) and a **lighting look** (12 trained styles, e.g. "hard
directional sunlight", "warm golden low front sun"). The demo renders a
light-direction sphere, composites it into the top-right corner of every frame,
and feeds the result as in-context conditioning to
[LTX-2.3-22B](https://huggingface.co/Lightricks/LTX-2.3) with the
[Relight IC-LoRA](https://huggingface.co/Lightricks/LTX-2.3-22b-IC-LoRA-Relight).

## How it works

This Space is a faithful port of the author's ComfyUI single-stage distilled
V2V IC-LoRA workflow (`LTX-2.3_Relight_ICLoRA_SingleStage_Distilled.json`) to
the official `ltx_pipelines` / `ltx_core` Python packages:

1. **Sphere render** — a pure-Python ray-tracer replicates the ComfyUI
   `SphereLightNode` Three.js scene (camera, unit sphere on a ground plane,
   directional light from the chosen azimuth/elevation/hardness).
2. **Composite** — the rendered sphere is resized to 143×143 px and composited
   into the top-right corner (22 px margin) of every frame, which is then
   scaled to 1280×704 and re-encoded at 24 fps.
3. **Conditioning** — the composited clip is passed as a
   `VideoConditionByReferenceLatent` (the IC-LoRA reference-latent stream), not
   as a first-frame image condition.
4. **Denoise** — a single distilled diffusion stage (`ICLoraPipeline`,
   `skip_stage_2=True`, 8-step distilled sigma schedule) denoises a fresh
   video latent guided by the reference and the text prompt.
5. **Decode** — the video latent is decoded with the video VAE; the output is a
   relit version of the source clip.

The 22B transformer is loaded with FP8 casting to fit the ZeroGPU memory budget.

> First launch downloads ~70 GB of weights (LTX-2.3 distilled checkpoint +
> Gemma-3-12B text encoder), so the initial boot is slow; subsequent runs use
> the cache.

## Tips

- **The sphere drives the light direction.** The model was trained to steer
  lighting based on the rendered ball in the top-right corner — without it,
  the model will not relight.
- **The lighting look is in the prompt.** Each of the 12 trained looks (e.g.
  "hard directional sunlight", "warm golden low front sun") is combined with
  the trigger phrase `relight the video to match the light-direction ball.` to
  form the text prompt.
- **Exterior clips work best.** The LoRA was trained on exterior scenes.
- **Keep clips short** (3–5 seconds). Longer clips need more VRAM and time.