Element: layer.brightness
Element: layer.brightnessnumeric
The color brightness for layer. All graphics on this layer have their brightness adjusted by this factor. Brightness adjustment enables the red, green and blue components of a graphic item's colors to be uniformly increased, similar to a brightness dial on a TV. A brightness value can have a range -1 through 1: -1 for black, 0 for no change, 1 for white.
If the graphic primitives themselves on the layer have a brightness defined, then this brighntess is applied cumulatively.
The value of this element can be redefined.
The brightness of new layers is 0 by default.