Sharpen Image

Make soft photos look crisp.

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Sharpen Image Online

Make soft photos look crisp. This tool applies an unsharp mask, the same technique used by Photoshop, GIMP and camera software, with three adjustable settings. Load an image, compare the original and sharpened versions side by side, and download the result.

How unsharp masking works

Despite the name, unsharp masking sharpens. The image is first blurred; the blurred copy is subtracted from the original, which leaves only the edges and fine details (the "mask"). That difference is multiplied by the Amount and added back to the original. Edges become higher in contrast — dark sides darker, light sides lighter — and the eye perceives this as sharpness.

  • Amount (0–500%): strength of the effect. 50–150% is a natural range for photos.
  • Radius (1–10 px): size of the blur used to find edges. Small values bring out texture such as hair, fabric and text; large values increase local contrast and make the whole picture "pop".
  • Threshold (0–64): minimum brightness difference that counts as an edge. Raise it to 4–10 to keep skin, sky and noise smooth while sharpening real details.

When to sharpen

Sharpening is usually the last step: after resizing, cropping and color correction. Downscaled images lose crispness and almost always benefit from a light sharpen. Photos from phones with heavy noise reduction, scanned documents, product photos for online shops and screenshots enlarged for presentations are other good candidates. Avoid sharpening images that will be compressed heavily as JPG; the extra edge detail costs file size.

Tips

Zoom in on the preview while adjusting. If you notice halos or grain, reduce the amount or increase the threshold. For the opposite effect, use the blur style in the Censored Image tool; for color adjustments try Instagram Filters.

Frequently Asked Questions

Only partly. Sharpening increases contrast along edges, which makes slightly soft photos look crisper. It cannot recover detail that was never captured, so a badly blurred photo will look harsh rather than sharp.

Amount is how strongly edges are boosted. Radius is how wide the boosted edge is: 1 px for fine detail, larger for overall punch. Threshold skips small differences so smooth areas such as skin and sky are not made noisy.

That is over-sharpening. Lower the Amount or the Radius. Halos are most visible on high-contrast edges like dark buildings against a bright sky.