The green-red component (negative values are green, positive values are red)
Optional
alphaThe alpha (opacity) component (0-1), optional
The blue-yellow component (negative values are blue, positive values are yellow)
Optional
illuminantThe reference white point used for this color
The lightness component (0-100)
Represents a color in the CIE Lab color space.
The CIE Lab color space is designed to be perceptually uniform, meaning that a change of the same amount in a color value should produce a change of about the same visual importance. It's device-independent and based on the CIE XYZ color space.