Image Sharpener
Apply a 3×3 unsharp-mask convolution to make a soft photo crisp. Adjustable strength.
Quick answer: Apply a 3×3 unsharp-mask convolution to make a soft photo crisp. Adjustable strength.
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Frequently asked questions
- When is sharpening helpful?
- After downscaling a large photo, after camera shake, on out-of-focus phone shots and on screenshots that look slightly soft on Retina displays. Don't sharpen images that are already crisp — it just adds grain.
- Will sharpening recover detail that wasn't captured?
- No. Sharpening boosts the edge contrast that's already there; it cannot invent texture. For low-resolution photos, our Upscale Image tool gives better results.
- What strength should I pick?
- Start at 0.5–1.0 for natural-looking sharpening. Above 2.0 you'll see haloing around edges, which is usually too much for portraits but fine for technical diagrams.
- Are my images uploaded?
- No — the convolution runs in your browser via the canvas API. Even big photos stay on your device.
- Does it work on transparent PNGs?
- Yes — the alpha channel is preserved, so logos and icons keep their transparency after sharpening.