layer.brightness < number>

Brightens or darkens a layer. Brightness is defined with a number. Setting brightness to 0 produces a completely black layer, while the value that produces a completely white layer depends on the color of your layer or image.
译：亮或变暗层。 亮度是用一些定义。亮度设置为0会产生完全黑色层，而会产生完全白层的价值取决于你的图层或图像的颜色。

layerA = new Layer
layerA.brightness = 10