Flux.3 Klein

FLUX 3 Image Klein is a 5.6B open weights image model from Black Forest Labs. One model handles text-to-image, editing with up to 10 reference images, and layout control with bounding boxes, at resolutions up to 4K.

Originally released by Black Forest Labs on Hugging Face. All credit for the model goes to the Black Forest Labs team. Civitai hosts a mirror so creators can generate with it on-site and train against it. Head to the original repo for the reference code and updates.

Two versions

• Klein is the distilled model: 16 steps with no guidance, about 6x faster than Base. BFL recommends it for generation and editing.

• Klein Base is the undistilled model: 50 steps at CFG 3.5. BFL recommends it for fine-tuning, LoRA training and research. LoRAs trained on Base can also be used on Klein, with partial compatibility.

Files

Each version carries the diffusion model in bf16, int8 and nvfp4, from BFL's ComfyUI release. The int8 files run on an 8 GB GPU (RTX 3070 class), and nvfp4 needs a Blackwell GPU. The text encoder and VAE ship in the ComfyUI repo.

Generating on Civitai

Both versions are in the Civitai generator for text-to-image and editing, with up to 10 reference images. Klein runs at fixed settings. Klein Base exposes steps, CFG and a negative prompt. Bounding-box layout is not in the generator yet.

License

FLUX 3 Image Klein is released under the FLUX Kommunity License. The model and anything derived from it, including LoRAs and fine-tunes, are for non-commercial use, and derivatives must be shared under the same license. Users and companies with under US$5M in annual revenue may use the images they generate commercially. Larger commercial use needs a license from Black Forest Labs.

This FLUX Model is licensed by Black Forest Labs Inc. under the FLUX Kommunity License. Copyright Black Forest Labs Inc.

Links

• FLUX 3 Image Klein

• FLUX 3 Image Klein Base

• ComfyUI files

• Black Forest Labs