CIELAB color space

Represents the CIELAB color space, its L, a and b axis with illustrative shades to make it easy to understand.

Edit and compile if you like:

% CIELAB color space
% Vilson Vieira  - http://automata.cc - 2013 - copyleft
\documentclass{article}
\usepackage{tikz}
\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
\setlength\PreviewBorder{10pt}%
\begin{document}
  
\begin{tikzpicture}[scale=1.5]
  % b* shade
  \path[draw, shade, left color=blue, right color=yellow, opacity=.6] 
    (0,0,0) node[below] {$-b*$} -- (5,2.0,0) node[below] {$+b*$}
    -- (5, 2.5, 0) -- (0, 0.5, 0) -- cycle;

  % a* shade
  \path[draw, shade, left color=green, right color=red, opacity=.6] 
  (0, 2.0, 0) node[below] {$-a*$} -- (5, 0, 0) node[below] {$+a*$} 
  -- (5, .5, 0) -- (0, 2.5, 0) -- cycle;
    
  % L* shade
  \path[draw, shade, top color=white, bottom color=black, opacity=.6] 
    (2.65, -1.85, 0) node[right] {$L* = 0$} -- (2.65, 4.45, 0)
    node[right] {$L*=100$} -- (2.35, 4.3, 0)  -- (2.35, -2., 0) -- cycle;

  % b*-axis
  \draw[<->] (0,0.25,0) -- (5, 2.25, 0);
  % a*-axis
  \draw[<->] (0,2.25,0) -- (5, 0.25, 0);
  % L*-axis
  \draw[<->] (2.5,-1.90,0) -- (2.5,4.35,0);
\end{tikzpicture}
\end{document}