What Is FLUX?
FLUX is a next-generation image generation model developed by Black Forest Labs. The team, which includes the creators of Stable Diffusion, has created a model with FLUX that produces higher quality, better text understanding, and more natural images. Launched in 2024, FLUX has surpassed its competitors particularly in photographic realism and text rendering.
Key features of FLUX: - **Text understanding:** Can understand complex and long prompts very well - **Text rendering:** One of the most successful models at writing text within images (signs, posters, etc.) - **Natural appearance:** Fewer errors in human faces, hands, and anatomy - **Diverse styles:** Wide range from photography to illustration, anime to 3D rendering
FLUX Variants
FLUX comes in three different versions:
**FLUX.1 Schnell (Fast):** - Apache 2.0 license (free, open for commercial use) - Can generate images in 1-4 steps - The fastest version, ideal for real-time applications - Small quality trade-offs but huge speed advantage - Recommended for local use and personal projects
**FLUX.1 Dev (Developer):** - Open weights, free for non-commercial use - Produces high-quality images in 20-30 steps - Offers quality closest to the Pro model - Can be used in ComfyUI and other local interfaces - Can be fine-tuned by the community
**FLUX.1 Pro:** - Accessible only via API (Replicate, fal.ai, Together AI) - Highest quality - Suitable for commercial use - For enterprise projects and production environments
Prompt Writing Techniques
FLUX is a model that understands natural language prompts very well. Instead of comma-separated tag lists like in other models, you can use flowing sentences:
**Tag style (old method):** "beautiful woman, long hair, sunset, beach, photorealistic, 8k, professional photo"
**Natural language (ideal for FLUX):** "A young woman with flowing long hair walks along a sandy beach at sunset. The warm golden light illuminates her face as gentle waves crash behind her. Shot in the style of a professional fashion editorial with shallow depth of field."
FLUX prompt tips: - Describe the scene in detail, tell a story - Clearly specify lighting conditions - Specify camera angle and lens type ("shot on 35mm lens", "aerial drone perspective") - Use double quotes if you want to add text: a sign that reads "Hello World" - Negative prompts are generally not needed, FLUX produces clean outputs
Parameter Settings
**Recommended settings for FLUX.1 Dev:** - Steps: 20-30 (20 is sufficient for most cases) - CFG: 1.0 (FLUX works with low CFG, guidance of 3.5-7 is recommended) - Sampler: Euler - Scheduler: Normal or Simple - Resolution: 1024x1024, 1024x768, or 768x1024
**For FLUX.1 Schnell:** - Steps: 1-4 (4 steps gives the best quality) - CFG: 1.0 - Other settings the same
Note: FLUX exhibits different CFG behavior from Stable Diffusion models. High CFG values (7+) lead to poor results. Instead, use the "guidance" parameter.
API Usage
If you want to use FLUX via API, there are several options:
**Replicate:** You can run FLUX models directly on the Replicate platform. Python example:
- Install the replicate library with pip - Set your API token - Call the model with the replicate.run function - Send prompt and parameters as input
**fal.ai:** fal.ai offers lower pricing and fast inference. You can develop real-time applications with WebSocket support.
**Together AI:** An affordable alternative for batch operations and high-volume usage.
FLUX LoRA and Fine-Tuning
You can teach your own style or concept by training LoRA on the FLUX model:
- **AI Toolkit (kohya):** The most popular tool for FLUX LoRA training - **Training time:** Approximately 1-2 hours with 8GB+ VRAM (for 20-30 images) - **Data preparation:** 15-30 images with consistent style and quality is sufficient - **Ready LoRAs on Civitai:** Hundreds of community-trained FLUX LoRAs are available
FLUX.2 and the Future
Black Forest Labs is working on FLUX.2. Expected innovations: - Higher resolution (native 2K and 4K support) - Video generation integration - Better character consistency - Improved inpainting and outpainting - Multi-language support (improvement in non-English prompts)