How to Sharpen a Slightly Blurry Photo
Sharpening cannot invent detail that the camera never captured, but it can make soft edges crisp again. The standard method is the unsharp mask, and its three settings tell you exactly what it will do.
What sharpening can and cannot fix
Good candidates are photos that look slightly soft after resizing, scans, phone pictures in low light, and product shots that are close to sharp. Poor candidates are photos that are clearly out of focus or smeared by motion. There, the edges were never recorded, and sharpening only makes the blur look harsh and noisy.
The three unsharp mask settings
- Amount: how much edge contrast is added; 100% doubles the difference at edges.
- Radius: how wide the edge effect is, in pixels. Use under 1 for fine detail and 1-2 for general crispness. Large radii act as local contrast.
- Threshold: how different a pixel must be from its neighbours before it is sharpened. Raise it to protect skin, sky, and noise.
A reliable workflow
Resize first, then sharpen: shrinking an image softens it, and sharpening for the final size looks best. Start gently (about 80-150%, radius 0.8-1.2, threshold 2-4) and judge at 100% zoom, not in a scaled-down preview. ToolkitPoint's Sharpen Image shows a 1:1 before-and-after crop for this reason. If you see bright halos around edges, lower Amount or Radius. If flat areas turn grainy, raise Threshold.
Save it well
Save photos as JPG at high quality, and graphics or text as PNG. Keep the original. Sharpening is destructive, and applying it twice usually looks worse than a single, well-judged pass.
Primary sources and further reading
Last reviewed: September 28, 2026