Sharpen

Last updated: January 8, 2026

Sharpen

Sharpen increases perceived sharpness by enhancing edges (high-frequency details). It’s useful for correcting images that look soft after resizing, or making text/logos look crisper.

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sharpen

Description

Sets the sharpening strength (sigma). Higher values produce a stronger sharpening effect, but depending on the image, it may also increase noise/grain.

Format

?sharpen={sigma}

Supported range

• 0.3 ~ 20

Examples

Request	Result
?sharpen=1.2	Apply light sharpening
?sharpen=3	Apply stronger sharpening (may increase noise)

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Using with other options

• Applying sharpen after downscaling with width often helps reduce the slight softness introduced during resizing.

?width=800&sharpen=1.0

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Recommended starting points

• A good starting range is 1.0–1.5.

• For logos/text, you’ll often notice a clear difference around ~2.0.

• For photos with lots of smooth areas (skin, gradients), higher sharpening can look harsh or noisy—start low and increase gradually.