Layer Background Color. Specifies the background color and opacity of the current layer.
Gray, RGB, or CMYK color value, with or without alpha.
Transparent and semi-opaque areas within the bounding rectangle of the layer are filled with the specified color* after*
extend= are applied.
Layer attribute. Applies to current layer or to layer 0 if
layer=comp. Ignored by effect layers.
color is assumed to exist in the working color space corresponding to the pixel type of
color is converted accurately if the final layer image has a different pixel type.
0,0,0,0 (fully transparent).