Sharpen in four steps
- Open the soft photo. Drop, paste or choose it. It is decoded in this tab; nothing is uploaded.
- Set radius and amount. Radius is the size of the detail lifted, in pixels; amount is how much. Start at 1.2 px and 120%, and watch the 100% loupe rather than the fitted view.
- Hold the halos back. The halo limiter keeps each pixel near the range of its neighbours in the original, which is where bright rims on dark edges come from. Threshold leaves skin and sky alone.
- Save, or keep the original. Saved at full size with a receipt naming every setting. The original is always one button away, byte for byte.
Soft, or smeared?
Most photos that look unsharp are one of two things. A soft photo — a cheap lens, a little missed focus, a downscale — has edges that are present but gentle; sharpening is the right tool. A smeared photo — a hand that moved — has edges dragged in one direction; sharpening doubles them. The workspace measures which it is when the photo opens and tells you. For a smear, use motion deblur; for missed focus, try the out-of-focus mode.
| Radius | Width of the detail lifted, in source pixels (0.3–5). |
|---|---|
| Amount | How much of that detail is added back (0–300%). |
| Threshold | Differences under this many levels are left alone (0–20). |
| Halo limiter | Clamps each pixel to near the local range of the original. |
Where sharpening goes wrong
- Movement blur: sharpening exaggerates the smear. Deblur it instead.
- JPEG blocks and WhatsApp compression get sharpened too; raise the threshold or lower the amount.
- Noise in night shots turns to grain. Use a larger threshold and a lower strength.
- It adds no resolution. A thumbnail sharpened is still a thumbnail.
Questions
What is the difference between sharpening and deblurring?
Sharpening raises contrast at edges that are already there; it suits a photo that is soft or flat. Deblurring undoes a measured smear — camera shake or missed focus — by deconvolving against a kernel. If the photo smeared in one direction, this page says so and offers the deblur instead, because sharpening a smear exaggerates it.
What do radius, amount and threshold do?
Radius (0.3–5 px) sets how wide the detail is that gets lifted: small for fine texture, larger for soft outlines. Amount (0–300%) sets how much is added back. Threshold (0–20 levels) leaves differences smaller than that alone, so smooth areas do not turn to grain.
Why is “brightness only” on by default?
Sharpening the red, green and blue channels separately puts coloured fringes on strong edges. Sharpening brightness only adds the same correction to all three channels, which keeps colours where they were.
Is this AI sharpening?
No. It is an unsharp mask — classical arithmetic you can read on the how-it-works page. It does not invent texture, faces or text, and the receipt says exactly what ran.
When won't this work?
On a photo smeared by movement (sharpening doubles the smear), on a heavily compressed photo (it sharpens the JPEG blocks too), and on detail that was never recorded. Sharpening makes existing edges crisper; it cannot add resolution.
Is my photo uploaded?
No. Decoding, sharpening and saving all happen in this browser tab.
Related
- Unblur an imageDiagnose the blur, then reconstruct it, with the kernel on a dial.
- Fix an out-of-focus photoThe defocus spread on a dial, limited to the part that is soft.
- Motion deblurOpen straight into the motion kernel, and read the dial before trusting what it rebuilds.
- Check if a photo is blurryMeasure blur before you upload: edge width, a heat map and a form checklist.
