A device-independent colour space that attempts to uniformly represent colour as we perceive it. 'L' is the lightness value, 'a' is the red/green opponency and blue/yellow is represented on the 'b' axis. It is used as a conversion space (PCS) when transforming from a source profile to a destination profile.
A device independent color space that can be used to describe the entire visual spectrum. This color space is being used in modern color management software to facilitate conversion of data from a scanner to a display, or from a display to an output device.
A perceptually linear color space.