How to Compare AI Upscalers: Topaz, Magnific, Real-ESRGAN
AI upscalers have revolutionized image enhancement, but with so many options available, how do you choose the best one for your needs? This guide explains how to objectively compare AI upscaler results using DualView, what to look for, and common pitfalls to avoid.
Why Comparison Matters
Not all AI upscalers are created equal, and more importantly, different upscalers excel at different types of content. An upscaler that works great on photos may produce artifacts on anime. The only way to know which works best for your use case is systematic comparison.
What to Look For
Edge Sharpness
Are edges crisp without halos or ringing? Use focus peaking to compare edge definition.
Detail Preservation
Is fine texture preserved or smeared? Look at hair, fabric, foliage, skin texture.
Hallucination
Did the AI add details that weren't there? Check text, patterns, faces for invented content.
Noise Handling
How does it treat noise? Over-smoothing vs. amplifying noise vs. natural grain.
Color Accuracy
Are colors preserved or shifted? Some upscalers add saturation or change hues.
Artifact Types
What new artifacts appear? Blocking, ringing, pattern repetition, plasticky skin.
Comparison Workflow
Step 1: Prepare Test Images
Use a variety of test images that represent your actual use case:
- Photos with faces at different distances
- Images with fine text
- Shots with detailed textures (fabric, hair, foliage)
- Images with areas of solid color and gradients
- Low-quality source images (the real test)
Step 2: Run Both Upscalers
Process the same source image through both upscalers at the same scale factor (e.g., 4x). Make sure settings are comparable — if one has "enhance faces" enabled, enable similar options in the other.
Step 3: Load into DualView
- Drag and drop both upscaled images into DualView
- Use slider comparison to sweep between them
- Zoom to 100% to see actual pixel quality
- Enable focus peaking to compare edge sharpness
- Check the pixel inspector for fine details
Always compare at 100% zoom. Scaled-down previews hide artifacts and differences. The radial loupe tool helps inspect details without losing context.
Critical Areas to Check
Faces
Faces are where hallucination is most problematic. Compare:
- Eye detail — pupils, iris texture, eyelashes
- Skin texture — pores vs. plastic smoothness
- Hair — individual strands vs. painted look
- Teeth — are they invented or preserved?
Text
Text is unforgiving — you either get it right or you don't. Compare text legibility and look for invented characters or distorted letterforms.
Repeating Patterns
Brick walls, fences, fabric patterns — these often reveal artifacts like pattern repetition, moiré, or loss of regular structure.
Common Upscaler Tradeoffs
| Characteristic | Conservative Upscaler | Aggressive Upscaler |
|---|---|---|
| Sharpness | Softer, but faithful | Very sharp, may overshoot |
| Detail | Preserves what exists | May invent detail |
| Artifacts | Fewer artifacts | More artifacts possible |
| Best for | Archival, accuracy matters | Creative, perception matters |
Using Quality Metrics
DualView can calculate SSIM and PSNR when comparing to a reference. For upscaling, these metrics are tricky because you don't have a "true" high-res reference. However:
- If you have high-res originals, downscale them and upscale back to measure accuracy
- SSIM can show which upscaler preserves structure better
- Visual comparison is still essential — metrics miss perceptual quality
Export Your Comparison
Once you've identified the best upscaler, use DualView's export feature to create a before/after video showing the difference. This is useful for:
- Client presentations
- Portfolio pieces
- Documentation of your process
- Social media content