The default value is false.

This option attempts to determine the average level of brightness of the given hue and will adjust the brightness level of all pixels with that hue so that the virtual bulb operation will convert those pixels to pure white. This operation should only be used on images with a white, or nearly white, background.

Use this operation if there are "shadows" of the dropped color left in the output image.

An exception will be thrown if you attempt to set this HueRadius option with the VirtualBulbOptions.Extract option set to true.

Reference