Threshold
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.
Original image
Threshold filter applied
Parameters in the Inspector
Threshold:
Sets the threshold of selection for color substitution. The threshold determines
what is considered light and what is considered dark in the object.
Smoothness:
Sets the smoothness of transition between the substituted colors.
Dark Color:
Sets the color used to represent the dark interpreted areas of the object. The
color controls can be expanded with the disclosure triangle to include Red, Green, and
Blue sliders, for more precise color selection.
Light Color:
Sets the color used to represent the light-interpreted areas of the object.
The color controls can be expanded with the disclosure triangle to include 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.
HUD Controls
The HUD contains the following controls: Threshold, Smoothness, Dark Color, and Light
Color.
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Chapter 19
Using Filters