The Threshold tool allows controlled color conversion and reduction of the active layer or selection. It will reduce the image to black and white only.
The Threshold tool provides a visual graph of the intensity values of the active layer or selection. Specific areas can be targeted as the base from which to take the information from which to build the black and white representation. The intensity range can be interactively selected by clicking Button1 and dragging.
The Threshold Range input boxes allow manual selection of the upper and lower intensity ranges.
The Preview toggle allows the dynamic updating of the active layer or selection while changes are made to the intensity level range.