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.

`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)

Using with other options

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

?width=800&sharpen=1.0

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.