The creation of the CIE L*a*b* model, also known as CIELAB came in 1976.

• In this model L* defined lightness, or luminous, this ranges from 0-100, black to white.
• a * indicates the red to green value: positive a* values appear reddish and negative a* values appear greenish, 128 to -128
• b* denotes the yellow to blue values:positive blue values are yellowish while negative b* values are bluish. 128 to -128
• All colors of the same lightness lie in a plane and lightness varies vertically along the L* axis.

The real important aspect of the color space is that it is device independent - completely independent of environment, mood, or device - and therefore objective in defining color. It's theoretically, that's why it's independent. It's a fixed standard that means the values will always represent the same color. L*a*b* values don't change unlike when we reference RGB; we have to say "which "RGB."

It also matches the processes taking place in the human perception of color. After red, green and blue cones within the eye have been stimulated, a further processing stage takes place and the three sensations are generated:

• a red-green sensation
• a yellow-blue sensation
• a bright sensation
  

There are 3 types of cones: roe, beta, gamma, basically RGB. You have the most rods that can see reds and greens and the human eye has the least of the blue receptors. Rods see light in black and white.

The CIELAB color model caters for these three sensations. L*a*b* is perceived color, i.e. relative to the white point. 

We use L*a*b*, because it is the universal translator and the 3D model contains both RGB and CMYK. This color space is plotted at right angles to one another. Equal distance in the space approximately represents equal color distance. 

See CIE (Commission Internationale de l'Éclairage).