Inpainting and Outpainting Advanced Techniques: ComfyUI Guide 2025

Inpainting replaces parts of images. Outpainting extends them beyond original boundaries. Together, they're the foundation of AI image manipulation—and advanced techniques unlock capabilities that basic tutorials never cover.

Quick Answer: Advanced inpainting uses specialized models (JuggernautXL Inpaint), soft inpainting for seamless blends, and mask blur for natural edges. Outpainting works best with directional prompts, multiple passes, and careful attention to aspect ratio changes.

Inpainting: Beyond the Basics

Basic inpainting just masks and regenerates. Advanced inpainting produces edits that are genuinely undetectable.

Choosing the Right Model

Base Models: Can inpaint but weren't trained for it. Results often have visible seams or style mismatches.

Specialized Inpaint Models: Trained specifically for masked regeneration. Examples:

• JuggernautXL Inpaint
• RealisticVision Inpaint
• SD 1.5 Inpainting model

Specialized models understand how to blend with surrounding context far better than base models.

Mask Techniques

Hard Masks: Binary on/off. Clear boundaries but visible seams.

Feathered Masks: Gradual falloff at edges. Better blending but less precise control.

Soft Inpainting: ComfyUI feature that creates gradient blending at mask edges automatically.

For invisible edits, combine feathered masks with soft inpainting enabled.

Outpainting extends scenes beyond original boundaries

Denoising Strength Control

Denoising strength controls how much the masked area changes:

• 0.0-0.3: Subtle modifications, preserves original closely
• 0.4-0.6: Moderate changes, good for object replacement
• 0.7-0.9: Major changes, generates new content
• 1.0: Complete regeneration, ignores original

For seamless results, use lower denoising for texture fixes, higher for object replacement.

Outpainting: Extending Reality

Outpainting adds new content beyond image boundaries. The challenge is maintaining consistency with existing content.

Directional Prompting

Guide outpainting with direction-aware prompts:

Extending Right:

continuing landscape to the right, more mountains,
extending horizon, consistent lighting from left

Extending Down:

continuing to show legs and ground, forest floor,
fallen leaves, consistent perspective

Multi-Pass Outpainting

For large extensions, don't try to generate everything at once:

1. First Pass: Extend 20-30% beyond original
2. Second Pass: Use first output as input, extend again
3. Repeat: Until desired size reached

Each pass maintains better consistency than one massive extension.

Infinite Canvas Techniques

For panoramic creation:

1. Start with a center image
2. Outpaint left edge
3. Outpaint right edge
4. Outpaint top if needed
5. Outpaint bottom if needed
6. Blend overlapping regions

Tools like stablediffusion-infinity automate this process.

Combining Inpainting and Outpainting

The most powerful technique combines both:

Use Case: Replace background and extend

1. Inpaint to replace the original background
2. Outpaint to extend the new background
3. Result: Subject in new, expanded environment

Use Case: Remove object and fill extended space

1. Inpaint to remove unwanted object
2. Outpaint to add more scene in that direction
3. Result: Clean, larger image

Advanced ComfyUI Workflow

A professional inpainting workflow includes:

Load Image
    ↓
Create/Load Mask
    ↓
Load Inpaint Model (specialized)
    ↓
VAE Encode (masked)
    ↓
KSampler (with conditioning)
    ↓
VAE Decode
    ↓
Composite (blend with original)
    ↓
Save Image

Key nodes:

• VAE Encode for Inpainting: Properly handles masked regions
• Set Latent Noise Mask: Applies mask to latent space
• Composite: Blends result with original using mask

Dealing with Common Problems

Seams at Edit Boundaries

Solution: Increase mask blur, enable soft inpainting, use specialized inpaint models, lower denoising at edges.

Style Mismatch

Solution: Use the same model that created the original, match prompt style, consider img2img pass over the whole image to unify style.

Lighting Inconsistency

Solution: Add lighting direction to prompt, use reference images with ControlNet, post-process with color matching.

Perspective Errors

Solution: Use depth ControlNet to maintain perspective, provide vanishing point references, work with smaller outpaint regions.

Repeated Patterns

Solution: Vary prompts between passes, add "varied, diverse" to prompts, manually mask and regenerate repetitive areas.

Specialized Techniques

Transparent Object Inpainting

For glass, water, or translucent objects:

• Use lower denoising (0.4-0.6)
• Include "transparent, see-through" in prompts
• May need multiple passes for quality

Face Inpainting

For face-specific edits:

• Use ADetailer for automatic face detection
• Keep face-specific models loaded
• Lower denoising for subtle changes
• Consider separate face restoration pass

Text Removal

For removing text/watermarks:

• Mask slightly larger than text
• Use "clean background, no text" in prompts
• Multiple passes often needed
• Consider dedicated watermark removal models

Outpainting for Different Content

Landscapes

Works well because patterns are more forgiving.

extending landscape, continuous terrain, matching horizon line,
consistent sky, natural continuation

Portraits

Challenging—extending people rarely works well. Better to:

• Extend only background
• Crop to avoid extending the subject

Architecture

Moderate difficulty—perspective must be maintained.

continuing building architecture, consistent perspective,
matching architectural style, same lighting angle

Performance Optimization

Memory Management

Inpainting/outpainting at high resolution consumes significant VRAM:

• Process in tiles for large images
• Use lower working resolution, upscale after
• Enable attention slicing in ComfyUI

Speed Improvements

• Lower step counts work for inpainting (15-25 steps)
• Use SDXL Turbo/Lightning for faster iteration
• Preview at low resolution before final render

Frequently Asked Questions

Can I inpaint with Flux models?

Yes, Flux Fill is designed for this. It offers excellent quality but requires different workflow nodes than SDXL inpainting.

How large can I outpaint?

Practical limit is 2-3x original size per direction. Beyond that, use multiple passes.

Why do my inpainted areas look different in style?

Use specialized inpaint models and match prompts exactly. Consider a final img2img pass to unify style.

Can I inpaint video?

Frame-by-frame is possible but requires careful attention to temporal consistency. Dedicated video inpainting models work better.

What's the best model for realistic inpainting?

JuggernautXL Inpaint and RealisticVision Inpaint are top choices for photorealistic content.

Conclusion

Advanced inpainting and outpainting transform AI from image generation to true image manipulation. The key differentiators are: specialized models, proper mask handling, appropriate denoising settings, and iterative multi-pass approaches.

Master these techniques and you can seamlessly remove objects, extend scenes, and composite elements that appear genuinely part of the original image.