#000000 is in the device-dependent RGB colorspace. Its correlation to a device-independent colorspace depends on—you guessed it—the device. This (absence of a)

#000000 is in the device-dependent RGB colorspace. Its correlation to a device-independent colorspace depends on—you guessed it—the device. This (absence of a) color can be represented in L* a* b* coordinates as L* = 0. (a* and b* are then irrelevant)