RaahUPSC · Image Tools
Sharpen Image
Add bite to photos that look a little soft, such as a hand-held shot or a resized scan. One Strength slider controls how much edge contrast is added.
✓ No upload · ✓ No sign-up · ✓ No watermark
How to use Sharpen Image
- Upload one or more images.
- Set Strength between 0.1 and 2 (default 0.6).
- Zoom into the preview to check edges and text.
- Press Apply & Download to save the sharpened copies.
What sharpening can and cannot do
The tool runs a 3 × 3 sharpening kernel over every pixel: each colour value is boosted relative to its four neighbours, which increases contrast along edges. Low strengths around 0.3–0.7 make text and fine detail look crisper; values above 1.5 quickly add white halos and exaggerate noise.
Sharpening improves the impression of detail but cannot restore detail that the camera never captured. It works best on images that are slightly soft from resizing or light focus errors, not on badly blurred or shaken photos. Scanned documents and signatures often benefit from a gentle pass.
Limitations
- The calculation runs in JavaScript pixel by pixel, so very large photos (20+ megapixels) can take several seconds or slow down a phone.
- The outermost one-pixel border of the image is left unsharpened.
- Strong settings amplify JPG compression artefacts and sensor noise.
Frequently asked questions
Can this fix a blurry photo?
Only mildly soft ones. Motion blur or a badly out-of-focus shot cannot be recovered by simple sharpening.
What strength should I start with?
Try 0.5 for photos and about 0.8 for scanned text, then adjust while watching the preview.
Does it work on transparent PNGs?
Yes. Colour channels are sharpened while the transparency channel is left as it was.