When should I train a style LoRA instead of using reference images, and what do BFL's FLUX.2 klein guide say about dataset size, captions and trigger words?

Problem. A brand look must hold across hundreds of images, offline or at low cost. Conditions. FLUX.2 [klein] LoRA training with an ai-toolkit-style config in BFL's guide; check the klein model licence before commercial use (not read here). Method (documented). The worked example trains a style LoRA on a fully synthetic dataset (images generated with FLUX.1 [dev] and illustrative LoRAs): 27 training images with caption files. Captions should describe only what is in the image and no style descriptors, so the model learns style from the pixels; a unique trigger word in every caption (example GFX_IMPR5N) activates the style at inference without polluting the base vocabulary. Training length guidance in the guide: style LoRAs (10 to 20 images) 1200 to 1800 steps, character LoRAs (10 to 15 images) 800 to 1200, medium datasets (20 to 40 images) 1200 to 2000, large datasets (50+ images) 2000 to 3000; the example config uses 3000 steps and inference with 8 steps for a soft painterly look. Choose [inference]: reference images or a vendor style object (C3-B593-07) when you have a few approved frames, a hosted API and a per-image cost you accept; a LoRA when you have 15 to 30+ consistent frames, need local control and repeatable look at volume, and can budget a training run; seed reuse alone only repeats one prompt (C3-B593-08). Failure modes. Overfitting to subjects in the dataset (captions that omit style help); style bleeding into prompts that should not carry it; dataset images generated by other models carry their licence terms (inference: FLUX.1 [dev] outputs have their own terms not read here). Limitations. A single vendor's example; no comparison to reference methods was measured. Version/date. 2026-10-23. Cross-reference correction 2026-10-23 (discovery C3-B697-01): worker provisional ids replaced by published C3 ids: P-L1-5-07 -> C3-B593-07 (same_batch; at link verification 2026-10-23T23:35:19Z this producer identifier had no verified public Hub record; no public link is asserted here); P-L1-5-08 -> C3-B593-08 (same_batch; at link verification 2026-10-23T23:35:19Z this producer identifier had no verified public Hub record; no public link is asserted here). Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Training numbers are the guide's example; no evaluation of style fidelity is included. Licence of klein weights and of synthetic-data images not read. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://docs.bfl.ml/flux_2/flux2_klein_training_example.md",
      "note": "Overview; Training pipeline; Caption Strategy; Caption Strategy; Training tips; Training tips; decision rule"
    }
  ]
}