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Preserving underlying transparency during compositing


    The Preserve Underlying Transparency option specifies that the opaque areas of a layer display only when positioned over opaque areas in underlying layers. With this option, you can make a layer display only when it is positioned over the layer below it. It's useful for creating effects such as glints or light reflecting off a polished surface.

To preserve underlying transparency:

    Select the T option in the Layer Switches column for the appropriate layer.

    In the graphic at left, the T option is off and the alpha channel of the swirl in the top layer is honored, preventing the underlying layers from showing completely. In the graphic at the right, the T option is on, and the alpha channel of the underlying layers is honored, allowing them to show completely.