Sharpen

Enhances image detail using an unsharp mask technique.

Category: Effects Menu path: Effects > Sharpen

Ports

Port	Type	Direction	Description
in	imageRgba16f	input	Input image
out	imageRgba16f	output	Sharpened result

Parameters

Param	Type	Default	Description
amount	scalar	0.5	Sharpening intensity. 0 = no effect. Values above 1 produce aggressive sharpening. Keyframeable.
radius	scalar	1.0	Sample distance in texels for the unsharp kernel. Higher values sharpen coarser detail. Keyframeable.

Expose Channels

When enabled (E button on node header), adds input ports that override params via edge connections:

Port	Type	Overrides
amount_in	scalar	amount
radius_in	scalar	radius

How It Works

The shader uses a 4-tap cross kernel (left, right, up, down) at the specified radius to compute a local average. The sharpened result is original + amount * (original - average). This is the classic unsharp mask technique: it enhances the difference between each pixel and its neighbors, boosting edges and fine detail. Output is clamped to prevent negative values.

Usage Examples

Basic: Sharpen soft footage

1. Add a Sharpen node after your image source
2. Set amount to 0.5 and radius to 1.0
3. Fine detail is enhanced without introducing obvious halos

Creative: Over-sharpen for graphic effect

1. Set amount to 2-3 for an aggressive, crunchy look
2. Increase radius to 2-3 to exaggerate coarser detail
3. Combine with Posterize for a stylized graphic treatment

Tips

• Keep amount below 1.0 for natural-looking results on photographic footage
• Radius 1.0 sharpens fine pixel-level detail; radius 3-5 sharpens broader features
• Sharpening amplifies noise -- consider applying after noise reduction or on clean source material
• For final output sharpening, apply as the last effect before Output

Related Nodes

• Blur -- the opposite operation; soften instead of sharpen
• Edge Detect -- extract edges rather than enhancing them
• Levels -- adjust contrast to enhance perceived sharpness