Front-load subjects, use guidance scale 5-7 for production work, and push to 35+ steps for text rendering.
Prompting for Professional Results
The December 2025 release of Qwen Image 2512 addresses three persistent weaknesses in open-source text-to-image generation: rendering complex text (especially Chinese characters), creating photorealistic human faces without the distinctive artificial appearance, and producing natural textures in landscapes and materials. This 20B MMDiT model achieved top ranking among open-source models after 10,000 blind comparison rounds on AI Arena, while remaining competitive with closed-source systems.1
Prompt construction determines the quality differential between amateur outputs and professional results. The Multimodal Diffusion Transformer (MMDiT) architecture processes text and image tokens through bidirectional attention mechanisms, meaning the model weighs prompt information based on position and specificity.2 This guide provides the prompting techniques, parameter configurations, and API implementation details needed to integrate Qwen Image 2512 on fal into production applications.
Core Capabilities
Text Rendering Precision: The model handles complex typography, multilingual text (particularly Chinese), and accurate text-image composition. For marketing materials, signage, or any content with embedded text, this capability differentiates Qwen Image 2512 from competing models like FLUX.1 [dev].
Photorealistic Human Generation: The 2512 update reduces the distinctive artificial appearance in faces through improved facial detail rendering, age-appropriate features, and natural skin textures.
Natural Texture Fidelity: Landscapes, water surfaces, animal fur, and material textures render with improved detail and realism.
falMODEL APIs
The fastest, cheapest and most reliable way to run genAI models. 1 API, 100s of models
Supported Image Sizes
The fal API accepts predefined image size enums or custom dimensions. The model operates at approximately 1.6 megapixels, automatically scaling inputs to match this target.
| image_size | Resolution | Use Case |
|---|---|---|
| square | 1024x1024 | Social media, avatars |
| square_hd | 1328x1328 | Native resolution, maximum detail |
| landscape_4_3 | 1472x1104 | Product photography, presentations |
| landscape_16_9 | 1664x928 | Widescreen, video thumbnails |
| portrait_4_3 | 1104x1472 | Mobile content, portraits |
| portrait_16_9 | 928x1664 | Stories, vertical video |
For custom dimensions, pass width and height as an object. Native resolution (1328x1328) provides maximum detail but increases generation time by approximately 50% compared to 1024x1024.
Prompt Structure
The model weights information based on position. Front-load your primary subject to ensure it receives the most attention during generation:
Subject, Style, Details, Composition, Lighting
Effective: "Young woman with auburn hair in casual denim jacket, editorial photography style, natural makeup, soft focus background, golden hour lighting, high detail"
Ineffective: "Make me a nice picture of someone pretty with good lighting"
The first prompt provides clear subject hierarchy, specific style direction, and defined lighting. The second lacks actionable specificity.
Parameter Reference
Guidance Scale (Default: 5, Range: 0-20)
Classifier-free guidance controls prompt adherence. Higher values produce outputs matching the prompt more precisely but risk oversaturation; lower values allow creative interpretation.3
| Range | Behavior | Use Case |
|---|---|---|
| 2-4 | Creative interpretation | Abstract, artistic styles |
| 5-7 | Balanced adherence | Most production use cases |
| 8-10 | Strict following | Text rendering, technical work |
Inference Steps (Default: 28, Range: 1-50)
- 15-20 steps: Draft quality, fast iteration
- 25-30 steps: Production quality
- 35-45 steps: Maximum quality, complex compositions
Acceleration
none: Full quality, no shortcuts. Use for final renders.regular: Balanced speed and quality. Default for most workflows.high: Faster generation with quality trade-offs. Use for iteration.
API Implementation
The fal API supports both synchronous subscription and queue-based workflows. Pricing is $0.02 per megapixel.
import fal_client
result = fal_client.subscribe(
"fal-ai/qwen-image-2512",
arguments={
"prompt": "Professional headshot of 45-year-old executive, navy blazer, neutral gray background, soft studio lighting, natural skin texture",
"image_size": "square_hd",
"num_inference_steps": 28,
"guidance_scale": 5,
"seed": 42,
"enable_safety_checker": True
}
)
image_url = result["images"][0]["url"]
Key Parameters
seed: Integer for reproducible generation. The same seed and prompt produce identical outputs.negative_prompt: String describing elements to exclude (e.g., "blurry, distorted, watermark").num_images: Generate multiple images per request (default: 1).output_format: Options arepng,jpeg, orwebp.
Safety Checker Behavior
When enable_safety_checker is True (default), blocked content returns an empty images array. Check the response before accessing image URLs in production code.
Practical Examples
Product Photography
Prompt: "Single red rose in clear glass vase on white marble with black and gold veins, harsh directional shadow, high contrast, editorial style, clean negative space"
Parameters: guidance_scale: 6, num_inference_steps: 30, image_size: landscape_4_3
Text-Heavy Compositions
Prompt: "Vintage movie poster, bold red letters spelling 'REVOLUTION' across top third, art deco typography, textured paper background, 1920s aesthetic, ornate decorative borders, sharp text edges"
Parameters: guidance_scale: 7, num_inference_steps: 40, image_size: portrait_4_3
For text rendering, increase guidance scale (6-8) and inference steps (35-45) to improve legibility.
Style Consistency
For multiple images with consistent styling, combine a fixed seed with a style template:
Base style: "editorial photography, natural lighting, muted palette, film grain"
Append subject variations while maintaining seed value for consistent lighting and color treatment across generations.
Negative Prompts
Pass negative prompts as a separate parameter to exclude unwanted elements:
- General quality: "blurry, low quality, distorted, deformed, oversaturated, watermark"
- Portraits: "smooth skin, airbrushed, doll-like, plastic"
- Landscapes: "unnatural colors, HDR artifacts, oversharpened"
Common Mistakes
Contradictory instructions: "Photorealistic oil painting" confuses the model. Choose one primary style.
Vague descriptors: Terms like "beautiful" or "amazing" add noise without direction. Specify what constitutes quality.
Guidance too low for technical work: Product shots and text-heavy designs need guidance scale 5-7 for precision.
Ignoring composition: Without spatial instructions, the model defaults to centered compositions. Specify framing for dynamic results.
Workflow Optimization
Start with a three-tier approach:
- Draft prompts at 20 steps,
highacceleration - Refine at 28 steps,
regularacceleration - Final renders at 35-40 steps,
noneacceleration
The fal serverless architecture handles scaling automatically. For production integration with webhooks and queue management, see the Model Endpoints documentation.
Recently Added
References
-
QwenLM. "Qwen-Image-2512." Hugging Face, 2025. https://huggingface.co/Qwen/Qwen-Image-2512 ↩
-
Esser, Patrick, et al. "Scaling Rectified Flow Transformers for High-Resolution Image Synthesis." arXiv preprint arXiv:2403.03206, 2024. https://arxiv.org/abs/2403.03206 ↩
-
Ho, Jonathan, and Tim Salimans. "Classifier-Free Diffusion Guidance." arXiv preprint arXiv:2207.12598, 2022. https://arxiv.org/abs/2207.12598 ↩

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