Prompting Guide - FLUX.2 [klein]

Master narrative prompting for FLUX.2 [klein] - scene-first prose, lighting mastery, and multi-reference composition

FLUX.2 [klein] works best when you describe scenes like a novelist, not a search engine. Write flowing prose with lighting details, and the model delivers.

No prompt upsampling: [klein] does not auto-enhance your prompts. What you write is what you get—so be descriptive.

Write Like a Novelist

Describe your scene as flowing prose—subject first, then setting, details, and lighting. This gives [klein] clear relationships between elements.

Do this

“A woman with short, blonde hair is posing against a light, neutral background. She is wearing colorful earrings and a necklace, resting her chin on her hand.”

Not this

“woman, blonde, short hair, neutral background, earrings, colorful, necklace, hand on chin, portrait, soft lighting”

Basic Prompt Structure

Use this framework for reliable results:

Subject → Setting → Details → Lighting → Atmosphere

Element	Purpose	Example
Subject	What the image is about	”A weathered fisherman in his late sixties”
Setting	Where the scene takes place	”stands at the bow of a small wooden boat”
Details	Specific visual elements	”wearing a salt-stained wool sweater, hands gripping frayed rope”
Lighting	How light shapes the scene	”golden hour sunlight filters through morning mist”
Atmosphere	Mood and emotional tone	”creating a sense of quiet determination and solitude”

Lighting: The Most Important Element

Lighting has the single greatest impact on [klein] output quality. Describe it like a photographer would.

Instead of “good lighting,” write “soft, diffused light from a large window camera-left, creating gentle shadows that define the subject’s features.”

What to describe:

• Source: natural, artificial, ambient
• Quality: soft, harsh, diffused, direct
• Direction: side, back, overhead, fill
• Temperature: warm, cool, golden, blue
• Interaction: catches, filters, reflects on surfaces

Example lighting phrases:

• “soft, diffused natural light filtering through sheer curtains”
• “dramatic side lighting creating deep shadows and highlights”
• “golden hour backlighting with lens flare”
• “overcast light creating even, shadow-free illumination”

Word Order Matters

[klein] pays more attention to what comes first. Front-load your most important elements.

Priority: Main subject → Key action → Style → Context → Secondary details

Strong word order:

“An elderly woman with silver hair carefully arranges wildflowers in a ceramic vase. Soft afternoon light streams through lace curtains, casting delicate shadows across her focused expression.”

Subject and action lead.

Weak word order:

“In a warm, nostalgic room with antique furniture, soft afternoon light streams through lace curtains. An elderly woman with silver hair is there arranging wildflowers.”

Subject buried in description.

Prompt Length

Length	Words	Best For
Short	10-30	Quick concepts, style exploration
Medium	30-80	Most production work
Long	80-300+	Complex editorial, detailed product shots

Longer prompts work well when every detail serves the image. Avoid filler — each sentence should add visual information.

Style and Mood Annotations

Adding explicit style and mood descriptors at the end of your prompt can enhance consistency:

[Scene description]. Style: Country chic meets luxury lifestyle editorial.
Mood: Serene, romantic, grounded.

[Scene description]. Shot on 35mm film (Kodak Portra 400) with shallow
depth of field—subject razor-sharp, background softly blurred.

Image Editing

For image editing, prompts describe the transformation you want. Focus on what changes while letting the input image(s) provide the foundation.

Key principle: Reference images carry visual details. Your prompt describes what should change or how elements should combine—not what they look like.

Single-Image Editing

Edit Type	Prompt Pattern	Example
Style transfer	”Turn into [style]"	"Reskin this into a realistic mountain vista”
Object swap	”Replace [element] with [new element]"	"Replace the bike with a rearing black horse”
Element replacement	”Replace [element] with [new element]"	"Replace all the feathers with rose petals”
Add elements	”Add [element] to [location]"	"Add small goblins climbing the right wall”
Environmental	”Change [aspect] to [new state]"	"Change the season to winter”

Multi-Reference Editing

Combine multiple input images for style transfer and complex edits. When using multiple references, specify the role of each.

Writing Effective Prompts

Be specific about what changes and clear about the target state. Reference image locations when needed (e.g., “image 1”, “image 2”) and let the base image provide context.

Good prompts

• “Add dramatic storm clouds to the sky”
• “Change her dress from blue to deep burgundy”
• “Age this portrait by 30 years”
• “Change image 1 to match the style of image 2”

Avoid

• “Make it better”
• “Improve the lighting”
• “Make it more professional”
• “Fix the image”

Model Variants

Variant	Speed	License	Best For
[klein] 4B	Sub-second	Apache 2.0	High-volume workflows, local deployment (~13GB VRAM)
[klein] 9B	Sub-second	FLUX Non-Commercial	Production work, best prompt understanding
Base 4B/9B	Standard	Same as above	Fine-tuning, research (undistilled, higher diversity)

Try [klein] via API — Get started in minutes with sub-second generation. No GPU required. View API docs →

API models (4B, 9B) are step-distilled for speed. Base variants preserve full training signal for customization.

Best Practices Summary

Write in Prose, Not Keywords

Describe scenes as flowing paragraphs. “A weathered leather journal lies open on an oak desk, morning light revealing handwritten entries in faded ink” works better than “journal, leather, oak desk, morning light, handwriting.”

Lead with Your Subject

Put the most important element first. Word order signals priority to the model.

Describe Light Explicitly

Specify light source, quality, direction, and how it interacts with surfaces. Lighting descriptions have the highest impact on output quality.

Use Sensory Details

Include textures, reflections, and atmospheric elements. “Flaky croissant layers catching soft diffused light” is more evocative than “croissant on table.”

Add Style/Mood Tags (Optional)

End prompts with explicit style or mood annotations when you want consistent aesthetic results across multiple generations.

Simplify Multi-Reference Prompts

When using reference images, describe relationships and context—let the images provide visual details.

Be Specific with Transformations

For i2i editing, clearly state what should change and the target result. Avoid vague instructions.

Try [klein] via API

Sub-second generation from $0.014/image. No GPU required—start generating in minutes.

Download Weights

Run locally with open weights. 4B (Apache 2.0) or 9B (FLUX Non-Commercial).