Sharpen a Photo
Bring back the crispness a lens, a resize or JPEG compression softened away. This sharpener uses classic unsharp masking with adjustable strength, previews at 100 percent zoom, and costs nothing - your photo is processed by your own browser rather than shipped off to a server farm.
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How it works
- Open the soft photo and zoom the preview to 100 percent - sharpening can only be judged at actual pixel size.
- Raise the amount until edges look crisp, backing off the moment bright outlines appear.
- Toggle before/after on a detailed area like eyes, text or foliage.
- Export, ideally as the last step after any resizing.
Worth knowing
Unsharp masking - the technique behind nearly every sharpen button ever shipped - is beautifully indirect: the tool blurs a copy of your photo, subtracts that blur from the original to isolate the fine detail, then adds that difference back on top. Edges, where blur changes pixels the most, get amplified; smooth areas, where the blurred copy barely differs, are left nearly untouched. The name comes from the darkroom, where printers really did sandwich a blurred negative (the unsharp mask) with the original.
The failure mode is halos. Push the amount too far and each high-contrast edge grows a bright fringe on its light side and a dark fringe on its dark side - look along a roofline against sky or dark text on white and you will see glowing outlines. Halos are the giveaway of oversharpened photos everywhere, and once exported they are baked in. The fix is discipline: judge at 100 percent zoom and stop a notch before the edges start to gleam.
Be honest about what sharpening is: an edge-contrast trick, not deblurring. It exaggerates transitions that already exist, so a slightly-soft-from-resizing photo responds beautifully, while genuine focus misses and motion blur do not - there is no hidden edge for the algorithm to find. Sharpening also amplifies whatever else lives at the pixel scale, which means visible noise and JPEG artifacts get crunchier along with the detail.
Sequence matters more than most guides admit. Sharpen after resizing, never before: a strength tuned at full resolution turns harsh once the image is scaled down, and resampling partially undoes sharpening anyway. And if you are enlarging a photo, do the upscale first and sharpen the enlarged result.
Oversharpening announces itself as a bright halo one to three pixels wide along high-contrast edges - zoom to 100 percent and check a roofline against the sky before you export.
What this tool will not do
- It cannot rescue a genuinely out-of-focus shot - unsharp masking amplifies existing edges, it does not reconstruct missing ones.
- It will not remove motion blur; a streaked subject stays streaked, just with crunchier streaks.
- It amplifies noise and compression artifacts along with detail - heavily compressed photos have a low ceiling.
Questions people ask
Can you actually fix a blurry picture?
It depends on the blur. Mild softness from resizing or compression sharpens up well; true focus misses and motion blur cannot be undone by unsharp masking, because the edge information was never captured.
What is an unsharp mask?
A sharpening method that subtracts a blurred copy of the image from the original to isolate detail, then adds that detail back - boosting edge contrast without touching smooth areas much.
Why do my photos get glowing edges after sharpening?
Those are halos, the classic sign of too much sharpening. Reduce the amount until the bright fringes along high-contrast edges disappear at 100 percent zoom.
Should I sharpen before or after resizing?
After, always. Resampling softens and partially undoes sharpening, and an amount tuned at one size looks wrong at another.
How much sharpening is right for printing versus screens?
Prints absorb more - ink spread softens fine detail, so a print-bound file can take sharpening that would look slightly harsh on screen. For web use, stop at the first hint of a halo.
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