FLUX.2 JSON Prompt Builder for ComfyUI

A comprehensive suite of custom nodes for building structured JSON prompts for FLUX.2 image generation with precision and control.

🚀 Phase 1: Core Foundation (v1.0.0)

This initial release includes 6 essential nodes for basic FLUX.2 prompt construction:

• FLUX2_PromptAssembler 🎯 - Master output node for final JSON assembly
• FLUX2_SceneBuilder 🏗️ - Define scene context and environment
• FLUX2_StyleSelector 🎨 - Choose artistic style and rendering
• FLUX2_SubjectCreator 👤 - Create individual subjects with properties
• FLUX2_SubjectArray 📋 - Collect multiple subjects into arrays
• FLUX2_CameraRig 📷 - Complete camera parameter control

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📦 Installation

Method 1: ComfyUI Manager (Recommended)

1. Open ComfyUI Manager
2. Search for "FLUX2 Prompt Builder"
3. Click Install
4. Restart ComfyUI

Method 2: Manual Installation

1. Navigate to your ComfyUI custom nodes directory:

cd ComfyUI/custom_nodes/

2. Clone this repository:

git clone https://github.com/MushroomFleet/ComfyUI-FLUX2-JSON.git

3. Restart ComfyUI

Method 3: Direct Download

1. Download this repository as ZIP
2. Extract to ComfyUI/custom_nodes/ComfyUI_FLUX2_Prompt_Builder/
3. Restart ComfyUI

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🎯 Quick Start

Basic Product Photography Workflow

1. Add FLUX2_SceneBuilder node
   - Set scene_type: "Product Stage"

2. Add FLUX2_SubjectCreator node
   - description: "Minimalist ceramic coffee mug"
   - position: "Center foreground"
   - color_1: "#000000"

3. Add FLUX2_CameraRig node
   - preset: "Product Photography"

4. Add FLUX2_StyleSelector node
   - style_category: "Photorealistic"

5. Add FLUX2_PromptAssembler node
   - Connect all outputs to corresponding inputs
   - Copy the json_string output

6. Use the JSON in your FLUX.2 generation workflow

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📚 Node Documentation

FLUX2_PromptAssembler 🎯

Purpose: Master node that collects all prompt components and outputs final JSON.

Inputs:

• scene (optional): Scene description from SceneBuilder
• subjects (optional): Subject array from SubjectArray
• style (optional): Style description from StyleSelector
• color_palette (optional): Global color palette (array)
• lighting (optional): Lighting description (string)
• mood (optional): Mood description (string)
• background (optional): Background details (string)
• composition (optional): Composition rules (string)
• camera (optional): Camera object from CameraRig
• pretty_print (boolean): Format JSON with indentation
• remove_empty (boolean): Remove empty/null fields

Outputs:

• json_string: Formatted JSON text (copy this to FLUX.2)
• json_object: Python dict for further processing

Usage: This is your final node. Connect all your prompt components here and copy the JSON output to use with FLUX.2.

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FLUX2_SceneBuilder 🏗️

Purpose: Define the overall scene context and environment.

Inputs:

• scene_type (required): Preset scene type or "Custom"
  • Options: Studio, Interior, Exterior, Product Stage, Workshop, Office, Kitchen, Living Room, Urban Street, Natural Landscape
• custom_description (optional): Custom scene description
• environment_details (optional): Additional environmental context
• time_of_day (optional): Morning, Afternoon, Evening, Night, Golden Hour, Blue Hour
• weather (optional): Clear, Cloudy, Overcast, Rainy, Foggy, Snowy

Outputs:

• scene: Complete scene description string

Example:

scene_type: "Studio"
time_of_day: "Morning"
weather: "Clear"
→ Output: "Professional photography studio with seamless backdrop, morning lighting, clear conditions"

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FLUX2_StyleSelector 🎨

Purpose: Choose artistic style and rendering approach.

Inputs:

• style_category (required): Main style category
  • Options: Photorealistic, Film Photography, Digital Eras, Artistic, Cinematic, Technical
• style_preset (optional): Specific preset within category
• custom_style (optional): Custom style description
• quality_level (optional): Commercial quality, Editorial quality, Artistic expression, Experimental
• additional_modifiers (optional): Extra style details

Outputs:

• style: Complete style description string

Categories:

• Photorealistic: Commercial, editorial, documentary photography
• Film Photography: Kodak Portra 400, Fuji Velvia 50, Ilford HP5+, etc.
• Digital Eras: Modern digital, 2000s digicam, 90s aesthetic
• Artistic: Painting styles, illustrations, minimalist design
• Cinematic: Movie-inspired looks, film noir, Wes Anderson style
• Technical: Blueprint, scientific, x-ray, infrared

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FLUX2_SubjectCreator 👤

Purpose: Create individual subjects with detailed specifications.

Inputs:

• description (required): Detailed subject description
• position (optional): Manual position description
• position_horizontal (optional): left, center, right, etc.
• position_vertical (optional): top, middle, bottom, etc.
• position_depth (optional): foreground, midground, background
• action (optional): Dynamic action description
• pose (optional): Static pose description
• color_1 through color_4 (optional): Color specifications (hex or names)

Outputs:

• subject: Subject object for use in SubjectArray

Example:

description: "Vintage leather-bound journal with brass corners"
position_horizontal: "center"
position_depth: "foreground"
color_1: "#8B4513"
color_2: "#FFD700"
→ Creates subject object with all properties

Position Helpers:

• Horizontal: far left, left side, center, right side, far right
• Vertical: top, upper third, middle, lower third, bottom
• Depth: foreground, midground, background

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FLUX2_SubjectArray 📋

Purpose: Collect multiple subjects into an ordered array.

Inputs:

• subject_1 through subject_8 (optional): Subject objects from SubjectCreator

Outputs:

• subjects: Array of subject objects for prompt assembly
• subject_count: Number of subjects in array
• summary: Quick overview of all subjects

Usage: Connect multiple SubjectCreator nodes to different input slots. Empty slots are automatically filtered out. Order matters—subject_1 is typically the primary/foreground element.

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FLUX2_CameraRig 📷

Purpose: Complete camera parameter control for photorealistic results.

Inputs:

• preset (required): Camera preset or "None"
  • Options: Portrait, Product Photography, Landscape, Macro, Street Photography, Wide Angle
• angle (optional): Camera viewing angle
• angle_preset (optional): Eye level, High angle, Low angle, etc.
• distance (optional): Shot framing (Close-up, Wide shot, etc.)
• lens_mm (optional): Focal length (0-400mm)
• lens_description (optional): Lens type description
• f_number (optional): Aperture (f/1.4 - f/16)
• iso (optional): ISO sensitivity (0-6400)
• depth_of_field (optional): DOF description
• depth_preset (optional): Very shallow, Shallow, Moderate, Deep, etc.
• focus (optional): Focus description
• override_preset (optional): Custom values override preset

Outputs:

• camera: Camera object for prompt assembly
• camera_summary: Text summary of settings

Presets:

• Portrait: 85mm, f/2.0, shallow DOF, eye-level angle
• Product Photography: 85mm, f/5.6, moderate DOF, slight overhead
• Landscape: 24mm, f/11, deep DOF, wide shot
• Macro: 100mm, f/2.8, very shallow DOF, extreme close-up
• Street Photography: 35mm, f/5.6, moderate DOF, eye level
• Wide Angle: 16mm, f/8, deep DOF, expansive

Lens Guide:

• 16-24mm: Ultra-wide, landscapes
• 35-50mm: Natural perspective, versatile
• 85-135mm: Portrait, flattering
• 200mm+: Telephoto, compression

Aperture Guide:

• f/1.4-2.0: Very shallow DOF (portraits)
• f/2.8-5.6: Moderate DOF (products)
• f/8-16: Deep DOF (landscapes)

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🎨 Example Workflows

Example 1: Simple Product Shot

Goal: Black coffee mug on white background

SceneBuilder:
  scene_type: "Studio"
  
SubjectCreator:
  description: "Minimalist ceramic coffee mug with matte finish"
  position_horizontal: "center"
  position_depth: "foreground"
  color_1: "#000000"
  
StyleSelector:
  style_category: "Photorealistic"
  quality_level: "Commercial quality"
  
CameraRig:
  preset: "Product Photography"
  
PromptAssembler:
  [Connect all above outputs]

Generated JSON:

{
  "scene": "Professional photography studio with seamless backdrop",
  "subjects": [
    {
      "description": "Minimalist ceramic coffee mug with matte finish",
      "position": "center foreground",
      "color_palette": ["#000000"]
    }
  ],
  "style": "Ultra-realistic product photography with commercial quality, commercial quality",
  "camera": {
    "angle": "Slight overhead angle, 30 degrees",
    "distance": "Medium shot",
    "lens-mm": 85,
    "f-number": "f/5.6",
    "ISO": 200,
    "depth_of_field": "Moderate depth, product sharp",
    "focus": "Sharp focus on product details"
  }
}

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Example 2: Multi-Subject Scene

Goal: Tech workspace with laptop, coffee, and plant

SceneBuilder:
  scene_type: "Office"
  time_of_day: "Morning"
  
SubjectCreator #1 (Laptop):
  description: "Sleek modern laptop, open with glowing screen"
  position_horizontal: "right side"
  position_depth: "midground"
  color_1: "#C0C0C0"
  
SubjectCreator #2 (Coffee):
  description: "White ceramic coffee mug with steam rising"
  position_horizontal: "left side"
  position_depth: "foreground"
  color_1: "#FFFFFF"
  
SubjectCreator #3 (Plant):
  description: "Small succulent plant in terracotta pot"
  position_horizontal: "far left"
  position_depth: "midground"
  color_1: "#228B22"
  color_2: "#D2691E"
  
SubjectArray:
  subject_1: [Coffee - foreground priority]
  subject_2: [Laptop]
  subject_3: [Plant]
  
StyleSelector:
  style_category: "Photorealistic"
  additional_modifiers: "Clean, minimalist aesthetic"
  
CameraRig:
  preset: "Product Photography"
  
PromptAssembler:
  [Connect all outputs]

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🔧 Advanced Tips

Color Management

Hex Colors:

• Always use 6-digit hex codes: #FF0000 not #F00
• Format automatically corrects to uppercase with # prefix
• Validation ensures proper hex format

Color Strategies:

• Use subject-specific colors for precise control
• Global color_palette sets overall mood
• Subject colors override global palette

Position Strategies

Using Position Helpers:

position_horizontal: "center"
position_vertical: "upper third"
position_depth: "foreground"
→ Generates: "center upper third foreground"

Manual Position:

position: "Center foreground on polished concrete surface"
→ Uses exactly as written

Camera Tips

Start with Presets:

• Use presets as starting points
• Enable override_preset to customize
• Adjust individual parameters as needed

Photorealism Formula:

Realistic focal length (35-85mm)
+ Appropriate aperture (f/2.8-8)
+ Proper ISO (100-400)
+ Clear focus description
= Photorealistic results

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🛠️ Troubleshooting

"Subject description is required"

Solution: SubjectCreator requires a description. Fill in the description field.

JSON output is empty

Solution: Check that remove_empty is set appropriately. If all fields are empty, the output will be {}.

Camera preset not applying

Solution: Make sure override_preset is False. If True, manual settings override the preset.

Colors not appearing

Solution: Ensure hex codes start with # and are valid 6-digit hex (e.g., #FF0000).

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📅 Roadmap

Phase 2: Visual Control (Coming Soon)

• FLUX2_HexColorPicker: Visual color selection
• FLUX2_ColorPaletteGenerator: Harmony-based palettes
• FLUX2_LightingRig: Professional lighting setups
• FLUX2_CompositionGuide: Composition rules
• FLUX2_MoodController: Emotional tone control

Phase 3: Advanced Camera (Future)

• FLUX2_LensCharacteristics: Lens effects
• FLUX2_FilmStockSimulator: Film emulation
• FLUX2_AtmosphericEffects: Environmental atmosphere

Phase 4+: Production Tools (Future)

• Template system
• Batch processing
• Multi-reference management
• Natural language conversion
• And much more!

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🤝 Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Submit a pull request

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📄 License

MIT License - See LICENSE file for details

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📚 Citation

Academic Citation

If you use this codebase in your research or project, please cite:

@software{comfyui_flux2_json,
  title = {ComfyUI FLUX2 JSON: building structured JSON prompts for FLUX.2},
  author = {[Drift Johnson]},
  year = {2025},
  url = {https://github.com/MushroomFleet/ComfyUI-FLUX2-JSON},
  version = {1.0.0}
}

Donate:

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💬 Support

• Issues: GitHub Issues
• Discussions: GitHub Discussions
• Documentation: Full Course

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🙏 Acknowledgments

• Built for the FLUX.2 image generation model
• Inspired by the FLUX.2 JSON prompting capabilities
• Community feedback and testing

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📊 Version History

v1.0.0 (Phase 1) - Initial Release

• Core foundation nodes (6 nodes)
• Basic prompt assembly
• Scene, style, subject, camera control
• Preset libraries
• Documentation

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Ready to build precise, professional prompts for FLUX.2? Install now and start creating! 🚀