Clicking the “None Set” Channel Slot brings up the Texture Channel Pop that allows you to adjust the map’s Brightness and Contrast. This is helpful for creating an either more intense or ligher specular with the map settings.
You can use the Gamma, Contrast, Brightness, and Input and Output Level settings to adjust the brightness to either darken or lighten an image.
Check the Invert box to flip the color values to the opposite values.
will control how much the map will affect that Texture Channel. Lowering the Saturation
will bring the color closer to black and white.
Drop Down Wing
In addition to being able to drop textures into the slot, you can also Load From File. You can also choose Custom Layers from AE to set as the texture, see Using Videos as textures for more info.
Adjust how many times the texture repeats with UV Repeat and adjust the positon along the surface with UV Offset.