Unsharp Mask - Image Sharpening Tool
Unsharp Mask is a sharpening tool that makes image details look clearer by increasing contrast along edges. Despite its name, it does not blur the image — the term comes from a traditional darkroom technique where a blurred (“unsharp”) copy of the image was used to enhance sharpness.
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Sharpening Settings
Output Settings
Understanding the Controls
Unsharp Mask usually has three adjustable parameters: Amount, Radius, and Threshold.
Each one changes how the sharpening behaves.
Amount
- Controls how strong the sharpening effect is.
- Higher values make edges more pronounced; lower values keep the effect subtle.
- Start with a moderate value and increase it slowly until the image looks naturally sharp.
Radius
- Determines how wide the sharpening effect spreads from each edge (measured in pixels).
- A small radius sharpens fine details such as hair or texture.
- A larger radius affects broader edges like shapes or shadows.
- For most images, a small to medium radius produces the most natural result.
Threshold
- Controls which parts of the image are sharpened based on contrast differences.
- A low threshold sharpens everything - including noise or small tonal variations.
- A higher threshold limits sharpening to stronger edges, leaving smooth areas (like sky or skin) untouched.
- Adjust this slider if you see unwanted noise or grain being emphasized.
How to Use the Unsharp Mask Tool
Upload or open your image.
Use a high-quality image for the best results.
Start with low settings.
Begin with a small radius and moderate amount.
For example:
- Amount: around 100–200%
- Radius: 0.5–1.5 pixels
- Threshold: 0–5
Adjust the sliders gradually.
Increase the amount or radius until the edges look crisp, but not harsh.
If you see light or dark outlines (called “halos”) around edges, reduce the radius or amount.
Use the preview to compare before and after.
Check your image at full size (100% zoom) to see the real sharpening effect.
Save or download the sharpened image.
Once you’re satisfied, export the result.
Remember that sharpening is usually the final step before saving or sharing.
Tips for Best Results
- Don’t over-sharpen. Too much sharpening can create unnatural halos and highlight noise.
- Adjust based on image size. Smaller images often need a smaller radius; larger images may require a slightly higher one.
- Use a threshold for noisy images. If your photo has visible grain or noise, increase the threshold slightly to prevent sharpening those areas.
- Preview carefully. Always check both the overall image and detailed areas before applying the final effect.
Example Starting Points
| Image Type | Amount | Radius | Threshold |
|---|---|---|---|
| Fine detail (textures, landscapes) | 150–250% | 0.5–1.0 px | 0–2 |
| Portraits or smooth surfaces | 100-150% | 0.3-0.8 px | 3-8 |
| Large or high-resolution images | 200-300% | 1.0-2.0 px | 0-3 |
| Noisy or low-light images | 100-200% | 0.5-1.0 px | 5-10 |
These numbers are only guidelines - every image is different, and the best settings depend on its detail and contrast.
Common Issues and How to Fix Them
- Halos around edges: Lower the radius or amount.
- Too much noise: Increase the threshold.
- No visible change: Try increasing the amount slightly or lowering the threshold.
- Artificial look: Reduce all sliders gradually until the image looks more natural.
Summary
Unsharp Mask is one of the most effective and flexible ways to enhance image clarity.
By carefully adjusting Amount, Radius, and Threshold, you can make your photos look clean, crisp, and natural - without overdoing the effect.