Sharpen
Sharpens the current layer

Factor: Amount of sharpening

Gaussian blur
Gaussian blurs the current layer

Radius: Radius of pixels to blur with

Motion blur
Motion blurs the current layer (single-direction lowpass)

Angle: Direction to blur
Radius: Radius of pixels to blur with

Radial blur
Radially blurs the current layer (radial lowpass)

Radius: Radius of pixels to blur with

Zoom blur
Centered radial lowpass

Radius: Radius of pixels to blur with

Diffuse
Adds diffuse distortion