Reduces all colors in an image to a duotone, and optionally limits the range of midtones preserved in the image. The result is an extremely high-contrast image that defaults to black and white—but you can reduce the image to any two colors.
Adjust this filter using the parameter controls in the Filters Inspector:
Threshold: Sets the threshold of selection for color substitution. The threshold determines what is considered light and what is considered dark in the image.
Smoothness: Sets the smoothness of transition between the substituted colors.
Dark Color: Sets the color used to represent the dark interpreted areas of the image. Click the disclosure triangle to reveal individual Red, Green, and Blue sliders, for more precise color selection.
Light Color: Sets the color used to represent the light-interpreted areas of the image. Click the disclosure triangle to reveal individual Red, Green, and Blue sliders, for more precise color selection.
Correct For Alpha: Renders semitransparent pixels correctly. Enable this setting if the edges of the filtered image show artifacts.
Mix: Sets the percentage of the original image to be blended with the color-corrected image.