What is Image Sharpener?

Fix blurry or soft photos with adjustable sharpening filters. Uses unsharp mask convolution to increase edge contrast, so photos that are slightly out of focus or softened by compression get their details back.

The tool uses unsharp masking — a technique that exaggerates the contrast right at the edges of objects. Three sliders do the work: strength sets how aggressive the boost is, radius defines how wide the edge sharpening reaches (1–2 pixels for crisp detail, 3–5 for softer enhancement), and threshold tells the filter to ignore low-contrast pixels so noisy skin or flat sky stays clean. A before/after toggle lets you compare without committing.

How to use

1. Step 1 — Upload or drag-and-drop the image you want to sharpen (JPEG, PNG, or WebP).
2. Step 2 — Adjust the sharpening strength slider. Start low (25%) for subtle enhancement, go higher (75-100%) for heavily blurred images.
3. Step 3 — Toggle the before/after comparison to check the result, then download the sharpened image.

When to use

• Reviving slightly soft phone snaps so the subject's eyes and lashes pop again.
• Cleaning up screenshots where text edges look fuzzy after compression.
• Bringing back detail in scanned documents or old photos that lost crispness.

Result

Upload a slightly blurry smartphone photo. Set sharpening to 50% — text in the background becomes readable and facial features gain definition without introducing artifacts.

FAQ

Can sharpening fix a heavily blurred photo?

It can revive slight blur and softness, not motion blur or out-of-focus shots. Sharpening boosts edge contrast that's already there — if the original lacks information, no filter can invent it. Best results come from mild blur or compression softness.

What does the threshold slider actually do?

Threshold tells the filter to skip pixel pairs whose contrast difference is below a set value. Set higher and the sharpening hits only strong edges (text, hair, building outlines) while leaving smooth zones like skin and sky untouched — so you don't amplify noise.

Why does my image look noisier after sharpening?

Sharpening boosts contrast on every edge it finds, including the random pixel variation we call noise. Raise the threshold to skip low-contrast areas, or lower the strength. A radius of 1–1.5 px and threshold 10–20 usually keeps noise in check.

What file formats and sizes are supported?

JPEG, PNG and WebP up to about 20 MB. The image gets decoded, sharpened on a canvas at full resolution, and saved as a new file. Very large photos (above 30 MP) may take a few seconds because the convolution runs over every pixel.

Should I sharpen before or after resizing?

Sharpen at the size you intend to display. Sharpening before downscaling wastes the work, since the resize re-softens edges. For print, sharpen after scaling to the final print dimensions; for web, after exporting at the target pixel width.

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