SDXL Image Generation Skill

SDXL Image Generation Skill

Generate optimized prompts for SDXL and execute fast image generation via MLX.

When to Use

Use this skill when the user wants to:

• Generate images quickly (~8 seconds)
• Use LoRA models or the extensive SDXL ecosystem
• Iterate rapidly on concepts
• Use negative prompts to exclude elements
• Apply prompt weights for fine control

Key Differences from FLUX

Feature	SDXL	FLUX
Speed	~8s	~20-80s
Negative prompts	YES	No
Prompt weights	YES (light)	No
Text rendering	Weak	Excellent
LoRA ecosystem	Massive	Limited

Choose SDXL for: Speed, iteration, LoRAs, negative prompt control Choose FLUX for: Quality, text in images, natural language

Prompt Structure

[Subject], [descriptive details], [style], [quality boosters], [lighting], [composition]

Negative prompt:

[unwanted elements], [quality issues], [style to avoid]

Key Rules

DO:

• Use both natural language AND keyword-style prompts
• Apply gentle weights: (keyword:1.2) - max 1.4
• Use moderate negative prompts (shorter than SD 1.5 needed)
• Stick to native 1024x1024 or supported aspect ratios (16:9, 1:1, 9:16)
• Include quality boosters: 8K, highly detailed, sharp focus

DON'T:

• Use SD 1.5 embeddings (incompatible)
• Use extremely long negative prompt lists
• Exceed weight of 1.5 (often has no effect)
• Use arbitrary resolutions like 900x900
• Rely only on "masterpiece, best quality" (less effective in SDXL)

Quality Modifiers

Essential Boosters:

• 8K, ultra high resolution, highly detailed
• sharp focus, intricate details
• professional photography
• cinematic lighting, volumetric lighting

Photography Terms:

• DSLR, 50mm lens, f/2.8 aperture
• soft natural lighting, golden hour glow
• shallow depth of field, bokeh
• skin pores visible, fabric texture

Negative Prompt Templates

Universal (keep short):

low quality, blurry, bad anatomy, extra fingers, deformed hands, watermark

For Realistic Images:

cartoon, illustration, anime, painting, CGI, 3D render, unrealistic proportions, extra fingers, low quality, jpeg artifacts

For Artistic/Illustration:

photorealistic, photograph, 3D render, low quality, blurry, bad composition

Generation Commands

Standard Generation

./scripts/sdxl-generate.sh "YOUR PROMPT HERE"

Multiple Variations

./scripts/sdxl-generate.sh "YOUR PROMPT" --n_images 4 --n_rows 2

Workflow

When user requests an SDXL image:

1. Understand the request - Subject, style, what to avoid?

2. Construct prompt pair:

   • Positive: Subject + details + style + quality boosters
   • Negative: Elements to avoid + quality issues

3. Apply weights sparingly - Only for critical elements, max 1.3-1.4

4. Generate using the script

5. Iterate - SDXL's speed allows rapid refinement

Example Prompts

Photorealistic Portrait

Prompt: Portrait of a middle-aged man with salt-and-pepper beard, warm brown
eyes, weathered skin with visible pores, wearing a wool sweater, soft window
light from the left creating gentle shadows, shallow depth of field, intimate
documentary style, 8K, highly detailed

Negative: cartoon, illustration, anime, CGI, plastic skin, extra fingers,
deformed face, low quality, blurry

Fantasy Landscape

Prompt: Vast mountain valley at dawn, ancient stone ruins covered in moss in
the foreground, mist rolling through pine forests, snow-capped peaks catching
the first golden light, epic scale, cinematic composition, volumetric god rays,
fantasy concept art style, 8K ultra detailed

Negative: low quality, blurry, jpeg artifacts, text, watermark, modern buildings

Product Photography

Prompt: Luxury watch on polished black marble surface, dramatic rim lighting,
reflections on metal case, visible texture on leather strap, professional
product photography, commercial quality, sharp focus throughout, studio
lighting with soft gradient background

Negative: low quality, blurry, distorted proportions, floating objects,
cluttered background

Stylized Illustration

Prompt: Young explorer with a glowing lantern standing at the entrance of an
ancient library, towering bookshelves disappearing into shadow, dust motes
floating in light beams, warm amber and cool blue color contrast, detailed
illustration style, storybook aesthetic, intricate linework

Negative: photorealistic, photograph, low quality, simple, flat colors

Architectural

Prompt: Modern minimalist house with floor-to-ceiling windows, surrounded by
a Japanese garden with carefully raked gravel and sculptural pines, golden
hour light casting long shadows, architectural photography, clean lines,
professional real estate photography style

Negative: cartoon, sketch, low quality, distorted perspective, cluttered

Using Weights

Apply weights sparingly for emphasis:

(glowing lantern:1.3), ancient library, towering bookshelves

Weight guidelines:

• 1.1-1.2: Subtle emphasis
• 1.3: Noticeable emphasis
• 1.4: Strong emphasis (max recommended)

• 1.5: Often ignored or causes artifacts