Split B/W mode creates special B/W conversions by using
different color filters for the shadows and highlight areas.
Clicking one of the preset icons will activate the appropriate effect by setting the sliders below to certain values. The same presets can also be found in Photography Mode, B/W Quick Mode and Expert Mode. For more information about the presets, please read the Local Presets page.
The preset icons in the top row work fine with portrait photos whereas the second row produces more extreme effects that are more suitable for landscape photos.
The Shadow-Hue and Highlight-Hue sliders let you select individual color filters for the shadows and highlight areas during the B/W conversion. The Treshold slider lets you shift the borders between the shadows and highlights. A middle value of 128 defines shadow and highlight areas of equal width whereas a value of zero suppresses the shadow hue and a value of 255 suppresses the highlight hue. The Transition slider adjusts the smoothness between the shadow and highlight areas. A slider value of zero usually creates ugly aliased edges in the image, so it is best to use a higher value for a smooth transition. A value of 255 on the other hand blends the shadow/highlight borders too much and produces an B/W conversion that is very similar to that of the Color Filter method.
The two hyper links at the bottom let you switch to Photograph Mode or to Expert Mode. Alternatively you can also use the Mode combo box at the top for doing that.