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name: core-principles description: Universal prompting principles that apply to all FLUX models

Core FLUX Prompting Principles

These principles apply to all FLUX models and form the foundation of effective prompting.

1. Positive Descriptions Only

FLUX does NOT support negative prompts. Always describe what you WANT, not what you don't want.

Wrong Approach

a portrait of a woman, no glasses, no hat, no makeup

Correct Approach

a portrait of a woman with natural skin, clear face, bare head, visible eyes

See negative-prompt-alternatives.md for comprehensive replacement strategies.

2. Prompt Structure Formula

Build prompts using this structure for consistent results:

[Subject] + [Action/Pose] + [Style/Medium] + [Context/Setting] + [Lighting] + [Technical Details]

Example

A young woman with flowing auburn hair (subject)
dancing gracefully in mid-leap (action)
in the style of classical oil painting (style)
in a moonlit garden with roses (context)
soft diffused moonlight with subtle rim lighting (lighting)
medium shot, shallow depth of field (technical)

3. Specificity Matters

More specific prompts yield dramatically better results.

Vague (Poor Results)

a cat sitting

Specific (Excellent Results)

A fluffy orange tabby cat with bright green eyes sitting regally on a vintage
velvet armchair, afternoon sunlight streaming through lace curtains, warm
golden hour lighting, shallow depth of field, shot on medium format film

4. Natural Language Works Best

Write prompts as descriptive prose rather than keyword lists.

Keyword Style (Less Effective)

woman, portrait, beautiful, blonde, studio, professional, 8k, detailed

Prose Style (More Effective)

A professional studio portrait of a beautiful blonde woman in her thirties,
captured with soft studio lighting that accentuates her features, rendered
in stunning detail with natural skin texture and subtle catchlights in her eyes

5. Lighting is Critical

Always specify lighting - it has the single greatest impact on image quality.

Natural Lighting

• Golden hour - warm, soft, directional
• Overcast - soft, diffused, even
• Harsh midday - high contrast, strong shadows
• Dappled forest light - specular, organic patterns

Studio Lighting

• Softbox - even, professional
• Rim light - edge definition, separation
• Butterfly lighting - beauty, glamour
• Rembrandt lighting - dramatic, classic portraits

Atmospheric Lighting

• Volumetric fog - depth, mystery
• God rays - dramatic, spiritual
• Neon glow - urban, cyberpunk
• Candlelight - warm, intimate

Mood-Based Lighting

• Dramatic shadows - tension, noir
• High key - bright, airy, clean
• Low key - moody, mysterious
• Chiaroscuro - strong contrast, painterly

6. Word Order Matters

FLUX prioritizes elements that appear earlier in the prompt. Front-load important elements.

Less Effective

A forest background with soft lighting where a knight in shining armor stands

More Effective

A knight in shining armor stands in a forest, soft dappled lighting filtering
through the canopy

7. Medium Prompt Length

Optimal prompt length is typically 30-80 words (FLUX can handle up to 512 tokens).

• Too short: Lacks direction, generic results
• Too long: Can become unfocused
• Sweet spot: Enough detail to guide, not so much it confuses

8. Iterative Refinement

Build prompts iteratively:

1. Start with core subject and action
2. Add style and medium
3. Specify lighting and atmosphere
4. Include technical details
5. Refine based on results

Change one element at a time to understand what affects your output.