How to sharpen an image
- Add the photos you want to sharpen. You can drop them in, choose them or paste one.
- Set the Amount, then drag the before and after line over an edge to check for bright outlines.
- Download the sharpened image, or the whole batch as a zip.
How sharpening works and where it goes wrong
Sharpening doesn’t add detail. It finds edges, where light meets dark, and makes the step between them steeper. On a photo that is just a little soft, from a phone lens or focus that was slightly off, that is enough to make it look clean and crisp.
The blur used for the mask is small and scales with the image size, so it works on fine edges rather than large shapes. Push the amount too far and the same trick turns into problems:
- Halos. Thin bright and dark outlines appear around edges, most visible against skies and walls.
- Grain. Noise in dark or flat areas gets sharpened too and looks gritty.
- JPG blocks. Compression artefacts in a heavily compressed JPG become more visible.
Good and bad candidates
Sharpening works well on photos that were shrunk for the web, scanned prints, product photos and shots that are nearly in focus. It works poorly on motion blur, photos that are clearly out of focus, and small images that were enlarged. Those need a reshoot or a better original.
A good order for fixing a photo is crop, resize, adjust brightness and contrast, then sharpen last. Save as PNG between steps if you are running the image through more than one tool.