You can access this command from the main menu through Colors → Local Threshold….

Presets, Input Type, Clipping, Blending Options, Preview, Merge filter, Split view


	These options are described in .

Radius

Standard deviation of gaussian neighborhood average for computing local contrast. If 0 is used a global threshold is used instead of one based on local contrast.

Antialiasing

This sets a rough target of levels of accuracy for anti-aliasing, or set to 1 to disable anti-aliasing.

Threshold level

Thresholding level consists of two values. Change the lower threshold towards 0 to minimize shadows or towards 1.0 to minimize highlights. The high threshold decides the maximum values to include, above this it gets set to 0.