Flux Text-to-Image Tutorial

Learn to use Flux model for text-to-image generation.

Flux Model Introduction

Flux is the latest image generation model by Black Forest Labs, with excellent prompt following.

Model Versions

Version	Features	Use Case
Flux.1 Dev	Open source, high quality	Quality pursuit
Flux.1 Schnell	Fast, 4-8 steps	Quick preview
Flux.1 Pro	Closed API	Best results

Installation

Download Models

ComfyUI/models/unet/
flux1-dev.safetensors    # Dev version (~23GB)
flux1-schnell.safetensors # Schnell version

Download VAE

Flux needs separate VAE:

ComfyUI/models/vae/
flux_vae.safetensors     # Flux VAE

Basic Workflow

┌─────────────┐    ┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ LoadCheckp │ →  │ CLIPTextEn │ →  │ KSampler   │ →  │ VAEDecode  │
│ oint       │    │ code (x2)  │    │            │    │            │
└─────────────┘    └─────────────┘    └─────────────┘    └─────────────┘
     CLIPTextEncode  CLIPTextEncode

Sampling Settings

Dev Version Recommended

Parameter	Value	Description
Steps	20-50	More steps, higher quality
CFG	3.5-7	Flux less sensitive to CFG
DPM++ 2M	Recommended	Sampler
Karras	Optional	Smoother

Schnell Version

Parameter	Value
Steps	4-8
CFG	1.0

Prompt Tips

Clear Description

# Clear
a beautiful sunset over the ocean, golden hour lighting, cinematic

# Avoid too long
1 girl, beautiful face, long hair, blue eyes, smile, 8k, detailed

Quality Tags

Tag	Effect
8k, high detail	More details
masterpiece	Quality boost
best quality	High quality
photorealistic	Realistic style

Style Control

# Art style
oil painting style, impressionist

# Photography style
shot on Canon 5D, film grain

# Illustration
digital art, flat illustration

Negative Prompt

Flux needs less negative prompting, but can add:

# Common negatives
blurry, low quality, distorted, ugly

Image Sizes

Size	Use
512x512	Quick preview
768x768	Balance
1024x1024	High quality
Custom	As needed

Advanced

LoRA Support

Flux supports LoRA:

1. Use Apply Flux LoRA node
2. Set LoRA strength 0.5-0.8
3. Adjust CFG strength

ControlNet

Flux supports ControlNet:

1. Load ControlNet
2. Preprocess image
3. Adjust control weight 0.5-0.8

Troubleshooting

Q: Slow generation

A:

• Use Schnell version
• Reduce steps
• Use quantized models (FP8)

Q: Poor results

A:

• Check prompt clarity
• Try different CFG values
• Increase steps

Q: Out of VRAM

A:

• Use FP8 quantization
• Reduce image size
• Close other applications

Next Steps

• Flux Image-to-Image - I2I tutorial
• Flux ControlNet - ControlNet usage